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Liu C, Bartlet-Hunt S, Li Y. Precipitation, temperature, and landcovers drive spatiotemporal variability of groundwater nitrate concentration across the Continental United States. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 945:174040. [PMID: 38885704 DOI: 10.1016/j.scitotenv.2024.174040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 06/13/2024] [Accepted: 06/14/2024] [Indexed: 06/20/2024]
Abstract
Groundwater nitrate contamination, especially in agriculturally active regions, is a well-recognized environmental concern. Understanding how this contamination evolves across the continental USA (CONUS) and through time is important to designing effective mitigation strategies. Despite extensive research on nitrate contamination, no existing studies can accurately predict changes in groundwater nitrate concentrations over time across the CONUS. To bridge this gap, we compiled a comprehensive dataset for a systematic evaluation of the potential influence of climate dynamics, landcover changes, and crucial soil and geological properties on groundwater contamination. We employed an interpretable machine learning approach, using 293,775 groundwater nitrate observations and 12 independent variables, to estimate annual groundwater nitrate concentrations at the county level from 2001 to 2020. Our model is the first one capable of accurately forecasting temporal changes in groundwater nitrate concentration across the entire CONUS. Our analysis reveals county level groundwater nitrate concentration changes occurred over the past two decades, particularly in regions initially with high concentrations in 2001, ranging from -16.2 mg/L-N to +6.5 mg/L-N between 2001 and 2020. 27 counties in the country appeared to have new concentrations greater than or equal to the maximum concentration level (MCL) at least once during this period. We revealed direct relationships between groundwater nitrate concentrations and climate factors, including that temperature and precipitation dominate the interannual variability in groundwater nitrate concentration in 75.2 % of counties. Notably, we have established a clear correlation between groundwater nitrate concentration and precipitation. Specifically, when annual precipitation falls below a threshold of about 748 mm, an increase of precipitation can directly result in elevated nitrate concentrations in groundwater, indicating heightened vulnerability to contamination due to climate change. This study forms a pivotal foundation for forecasting groundwater nitrate concentration changes across the continent and assessing the potential impact of climate change on future groundwater nitrate concentrations.
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Affiliation(s)
- Chuyang Liu
- Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Shannon Bartlet-Hunt
- Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Yusong Li
- Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
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Massonnet C, Chuste PA, Zeller B, Tillard P, Gerard B, Cheraft L, Breda N, Maillard P. Does long-term drought or repeated defoliation affect seasonal leaf N cycling in young beech trees? TREE PHYSIOLOGY 2024; 44:tpae054. [PMID: 38769932 DOI: 10.1093/treephys/tpae054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 05/14/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024]
Abstract
Forest trees adopt effective strategies to optimize nitrogen (N) use through internal N recycling. In the context of more recurrent environmental stresses due to climate change, the question remains of whether increased frequency of drought or defoliation threatens this internal N recycling strategy. We submitted 8-year-old beech trees to 2 years of either severe drought (Dro) or manual defoliation (Def) to create a state of N starvation. At the end of the second year before leaf senescence, we labeled the foliage of the Dro and Def trees, as well as that of control (Co) trees, with 15N-urea. Leaf N resorption, winter tree N storage (total N, 15N, amino acids, soluble proteins) and N remobilization in spring were evaluated for the three treatments. Defoliation and drought did not significantly impact foliar N resorption or N concentrations in organs in winter. Total N amounts in Def tree remained close to those in Co tree, but winter N was stored more in the branches than in the trunk and roots. Total N amount in Dro trees was drastically reduced (-55%), especially at the trunk level, but soluble protein concentrations increased in the trunk and fine roots compared with Co trees. During spring, 15N was mobilized from the trunk, branches and twigs of both Co and Def trees to support leaf growth. It was only provided through twig 15N remobilization in the Dro trees, thus resulting in extremely reduced Dro leaf N amounts. Our results suggest that stress-induced changes occur in N metabolism but with varying severity depending on the constraints: within-tree 15N transport and storage strategy changed in response to defoliation, whereas a soil water deficit induced a drastic reduction of the N amounts in all the tree organs. Consequently, N dysfunction could be involved in drought-induced beech tree mortality under the future climate.
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Affiliation(s)
- Catherine Massonnet
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | - Pierre-Antoine Chuste
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | | | - Pascal Tillard
- UMR 5004, Biochimie et Physiologie Moléculaire des Plantes, INRAE/CNRS/Montpellier SupAgro/Université Montpellier, Place Viala, 34060 Montpellier, Cedex 2, France
| | - Bastien Gerard
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | - Loucif Cheraft
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | - Nathalie Breda
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | - Pascale Maillard
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
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Li N, Wang B, Zhou Y, Li H, Zhu Z, Dou Y, Huang Y, Jiao F, An S. Response of the C-fixing bacteria community to precipitation changes and its impact on bacterial necromass accumulation in semiarid grassland. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 354:120289. [PMID: 38367498 DOI: 10.1016/j.jenvman.2024.120289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 01/31/2024] [Accepted: 02/03/2024] [Indexed: 02/19/2024]
Abstract
Climate change-induced warming has the potential to intensify drought conditions in certain regions, resulting in uneven precipitation patterns. However, the impact of precipitation-induced changes on soil C-fixing bacterial community composition to changes and their subsequent effect on the accumulation of microbial necromass in the soil remains unclear. To address this knowledge gap, we conducted an in-situ simulated precipitation control experiment in semi-arid grasslands, encompassing five primary precipitation gradients: ambient precipitation as a control (contr), decreased precipitation by 80% and 40% (DP80, DP40), and increased precipitation by 40% and 80% (IP80, IP40). Our findings indicate that while an increase in precipitation promotes greater total bacterial diversity, it reduces the diversity of cbbM-harboring bacteria. The dominance of drought-tolerant Proteobacteria within the cbbM-harboring bacterial community was responsible for the observed increase in their relative abundance, ranging from 8.9% to 15.6%, under conditions of decreased precipitation. In arid environments characterized by limited soil moisture and nutrient availability, certain dominant genera such as Thiobacillus, Sulfuritalea, and Halothiobacillus, which possess cbbM genes, exhibit strong synergistic effects with other bacteria, thereby leading to a high nutrient use efficiency. Linear regression analysis shows that bacterial necromass C was significantly negatively correlated with cbbM-harboring bacterial diversity but positively correlated with cbbM-harboring bacterial community composition. Consequently, in the extreme drought environment of DP80, the contribution of bacterial necromass C to SOC was dramatically reduced by 75% relative to the control. Although bacterial necromass C was preferentially consumed as nutrients and energy for microorganisms, C-fixing microorganisms supplemented the soil C pool by assimilating atmospheric CO2. Bacterial necromass was primarily controlled by accessible C and N rather than by the total bacterial community composition and relative abundance. Our results provide compelling evidence for the critical role of the composition of the bacterial community and its necromass in the accumulation of SOC in semiarid grassland ecosystems.
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Affiliation(s)
- Na Li
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, 712100, China
| | - Baorong Wang
- College of Grassland Agriculture, Northwest A &F University, Yangling, 712100, China
| | - Yue Zhou
- Key Laboratory of Plant Nutrition and the Agro-environment in Northwest China, Ministry of Agriculture, College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Huijun Li
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, 712100, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhaolong Zhu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, 712100, China
| | - Yanxing Dou
- College of Forestry, Northwest A &F University, Yangling, 712100, China
| | - Yimei Huang
- Key Laboratory of Plant Nutrition and the Agro-environment in Northwest China, Ministry of Agriculture, College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Feng Jiao
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, 712100, China
| | - Shaoshan An
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, 712100, China.
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Xu S, Wang J, Sayer EJ, Lam SK, Lai DYF. Precipitation change affects forest soil carbon inputs and pools: A global meta-analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168171. [PMID: 37923258 DOI: 10.1016/j.scitotenv.2023.168171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/09/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023]
Abstract
The impacts of precipitation change on forest carbon (C) storage will have global consequences, as forests play a major role in sequestering anthropogenic CO2. Although forest soils are one of the largest terrestrial C pools, there is great uncertainty around the response of forest soil organic carbon (SOC) to precipitation change, which limits our ability to predict future forest C storage. To address this, we conducted a meta-analysis to determine the effect of drought and irrigation experiments on SOC pools, plant C inputs and the soil environment based on 161 studies across 139 forest sites worldwide. Overall, forest SOC content was not affected by precipitation change, but both drought and irrigation altered plant C inputs and soil properties associated with SOC formation and storage. Drought may enhance SOC stability by altering soil aggregate fractions, but the effect of irrigation on SOC fractions remains unexplored. The apparent insensitivity of SOC to precipitation change can be explained by the short duration of most experiments and by biome-specific responses of C inputs and pools to drought or irrigation. Importantly, we demonstrate that SOC content is more likely to decline under irrigation at drier temperate sites, but that dry forests are currently underrepresented across experimental studies. Thus, our meta-analysis advances research into the impacts of precipitation change in forests by revealing important differences among forest biomes, which are likely linked to plant adaptation to extant conditions. We further demonstrate important knowledge gaps around how precipitation change will affect SOC stability, as too few studies currently consider distinct soil C pools. To accurately predict future SOC storage in forests, there is an urgent need for coordinated studies of different soil C pools and fractions across existing sites, as well as new experiments in underrepresented forest types.
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Affiliation(s)
- Shan Xu
- Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Junjian Wang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Emma J Sayer
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom; Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa, Ancon, Panama, Republic of Panama
| | - Shu Kee Lam
- School of Agriculture and Food, University of Melbourne, Melbourne, Australia
| | - Derrick Y F Lai
- Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; Centre for Environmental Policy and Resource Management, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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Lv P, Sun S, Li Y, Zhao S, Zhang J, Hu Y, Yue P, Zuo X. Plant composition change mediates climate drought, nitrogen addition, and grazing effects on soil net nitrogen mineralization in a semi-arid grassland in North China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168282. [PMID: 37923269 DOI: 10.1016/j.scitotenv.2023.168282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 10/18/2023] [Accepted: 10/31/2023] [Indexed: 11/07/2023]
Abstract
Human activities induce alterations of the nitrogen (N) cycle, climate drought, and disturbance (e.g., livestock grazing) regimes at the global scale. Their individual, interactive, and combined effects on soil N cycling in grasslands are unclear. We investigated the N addition, drought, and grazing effects on the N mineralization, as well as their correlations with N-related variables, including the C4 species, shoot biomass (SB), root biomass (RB), plant total nitrogen (PTN), plant total carbon (PTC), soil total nitrogen (STN), soil total carbon (STC), and soil microbial N and C, during a three-year field experiment conducted in a semi-arid grassland in North China. The results showed that N addition increased the nitrate N (NO3--N) and ammonium N (NH4+-N) concentrations, whereas drought decreased the NO3--N concentration because of strengthened N limitation. Pronounced temporal variation in the N mineralization occurred under seasonal drought (maxima in August and September) and under its combination with N addition and grazing (minima in August). RB and the C4 species were positively correlated, whereas STC and the NO3--N concentration were negatively correlated with the N mineralization under the combined influence of the three factors. The structural equation model showed that at the site affected by all three factors, drought indirectly increased the N mineralization by reducing the NO3--N concentration, whereas N addition and grazing did not alter the N mineralization. N addition directly increased while indirectly reduced N mineralization by increasing the NO3--N concentration. Additionally, N addition and grazing increased the C4 species and decreased the STC, consequently enhanced N mineralization. These results highlight the predominant role of drought, when combined with N addition and grazing, in controlling the N mineralization. The N supply balance in semi-arid grasslands could be stabilized in response to increased N addition, climate drought, and grazing.
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Affiliation(s)
- Peng Lv
- Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China
| | - Shanshan Sun
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuqiang Li
- Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China
| | - Shenglong Zhao
- College of Resources and Environmental Engineering, Tianshui Normal University, Tianshui 741000, China
| | - Jing Zhang
- Information Center, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Ya Hu
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China
| | - Ping Yue
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China
| | - Xiaoan Zuo
- Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China.
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Xu G, Li G, Wu J, Ma W, Wang H, Yuan J, Li X. Effects of rainfall amount and frequencies on soil net nitrogen mineralization in Gahai wet meadow in the Qinghai-Tibetan Plateau. Sci Rep 2023; 13:14860. [PMID: 37684356 PMCID: PMC10491659 DOI: 10.1038/s41598-023-39267-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 07/22/2023] [Indexed: 09/10/2023] Open
Abstract
Global climate change has led to a significant increase in the frequency of extreme rainfall events in the Qinghai-Tibetan Plateau (QTP), thus potentially increasing the annual rainfall amounts and, consequently, affecting the net soil nitrogen (N) mineralization process. However, few studies on the responses of the soil net N mineralization rates to the increases in rainfall amounts and frequencies in alpine wet meadows have been carried out. Therefore, the present study aims to assess the effects of rainfall frequency and amount changes on the N fixation capacity of wet meadow soils by varying the rainfall frequency and amount in the Gahai wet meadow in the northeastern margin of the QTP during the plant-growing season in 2019. The treatment scenarios consisted of ambient rain (CK) and supplementary irrigation at a rate of 25 mm, with different irrigation frequencies, namely weekly (DF1), biweekly (DF2), every three weeks (DF3), and every four weeks (DF4). According to the obtained results, the increased rainfall frequency and amount decreased the soil mineral N stock and increased the aboveground vegetation biomass (AB) amounts and soil water contents in the wet meadows of the QTP. Ammonium (NH4+-N) and nitrate N (NO3--N) contributed similarly to the mineral N contents. However, the ammonification process played a major role in the soil mineralization process. The effects of increasing rainfall amount and frequency on N mineralization showed seasonal variations. The N mineralization rate showed a single-peaked curve with increasing soil temperature during the rapid vegetation growth phase, reaching the highest value in August. In addition, the N mineralization rates showed significant positive correlations with soil temperatures and NH4+-N contents and a significant negative correlation with AB (P < 0.05). The results of this study demonstrated the key role of low extreme rainfall event frequencies in increasing the net soil N mineralization rates in the vegetation growing season, which is detrimental to soil N accumulation, thereby affecting the effectiveness of soil N contents.
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Affiliation(s)
- Guorong Xu
- College of Forestry, Gansu Agricultural University, Lanzhou, 730070, China
- State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, 730070, China
| | - Guang Li
- College of Forestry, Gansu Agricultural University, Lanzhou, 730070, China.
- State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, 730070, China.
| | - Jiangqi Wu
- College of Forestry, Gansu Agricultural University, Lanzhou, 730070, China.
| | - Weiwei Ma
- College of Forestry, Gansu Agricultural University, Lanzhou, 730070, China
| | - Haiyan Wang
- College of Forestry, Gansu Agricultural University, Lanzhou, 730070, China
| | - Jianyu Yuan
- College of Forestry, Gansu Agricultural University, Lanzhou, 730070, China
| | - Xiaodan Li
- College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou, 730070, China
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Guo C, Wesche K, Mărgărint MC, Nowak A, Dembicz I, Wu J. Climate overrides fencing and soil mineral nutrients to affect plant diversity and biomass of alpine grasslands across North Tibet. FRONTIERS IN PLANT SCIENCE 2022; 13:1024954. [PMID: 36570963 PMCID: PMC9773210 DOI: 10.3389/fpls.2022.1024954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
INTRODUCTION Overgrazing and warming are thought to be responsible for the loss of species diversity, declined ecosystem productivity and soil nutrient availability of degraded grasslands on the Tibetan Plateau. Mineral elements in soils critically regulate plant individual's growth, performance, reproduction, and survival. However, it is still unclear whether plant species diversity and biomass production can be improved indirectly via the recovery of mineral element availability at topsoils of degraded grasslands, via grazing exclusion by fencing for years. METHODS To answer this question, we measured plant species richness, Shannow-Wiener index, aboveground biomass, and mineral element contents of Ca, Cu, Fe, Mg, Mn, Zn, K and P at the top-layer (0 - 10 cm) soils at 15 pairs of fenced vs grazed matched sites from alpine meadows (n = 5), alpine steppes (n = 6), and desert-steppes (n = 4) across North Tibet. RESULTS Our results showed that fencing only reduced the Shannon-Wiener index of alpine meadows, and did not alter aboveground biomass, species richness, and soil mineral contents within each grassland type, compared to adjacent open sites grazed by domestic livestock. Aboveground biomass first decreased and then increased along with the gradient of increasing Ca content but did not show any clear relationship with other mineral elements across the three different alpine grassland types. More than 45% of the variance in plant diversity indices and aboveground biomass across North Tibet can be explained by the sum precipitation during plant growing months. Structural equation modelling also confirmed that climatic variables could regulate biomass production directly and indirectly via soil mineral element (Ca) and plant diversity indices. DISCUSSION Overall, the community structure and biomass production of alpine grasslands across North Tibet was weakly affected by fencing, compared to the robst climatic control. Therefore, medium-term livestock exclusion by fencing might have limited contribution to the recovery of ecosystem structure and functions of degraded alpine grasslands.
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Affiliation(s)
- Chenrui Guo
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
- School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang, China
| | - Karsten Wesche
- Department of Botany, Senckenberg Museum of Natural History Görlitz, Görlitz, Germany
- International Institute (IHI) Zittau, Technische Universität Dresden, Zittau, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Mihai Ciprian Mărgărint
- Department of Geography, Geography and Geology Faculty, Alexandru Ioan Cuza University of Iaşi, Iaşi, Romania
| | - Arkadiusz Nowak
- Botanical Garden Center for Biological Diversity Conservation in Powsin, Polish Academy of Sciences, Warsaw, Poland
- Institute of Biology, University of Opole, Opole, Poland
| | - Iwona Dembicz
- Department of Ecology and Environmental Conservation, Institute of Environmental Biology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Jianshuang Wu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
- Department of Geography, Geography and Geology Faculty, Alexandru Ioan Cuza University of Iaşi, Iaşi, Romania
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Tang X, Fei X, Sun Y, Shao H, Zhu J, He X, Wang X, Yong B, Tao X. Abscisic acid-polyacrylamide (ABA-PAM) treatment enhances forage grass growth and soil microbial diversity under drought stress. FRONTIERS IN PLANT SCIENCE 2022; 13:973665. [PMID: 36119590 PMCID: PMC9478517 DOI: 10.3389/fpls.2022.973665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
Drought restricts the growth of alpine grassland vegetation. This study aimed to explore a new technical system to improve the drought resistance of forage grass. Qinghai cold-land Poa pratensis seedlings were used in the drought stress experiment. A combination of abscisic acid (ABA) and polyacrylamide (PAM) were used to affect the growth, leaf physiology, soil enzyme activity, and rhizosphere microbial diversity of P. pratensis. The fresh leaf weight and root surface area were significantly increased after ABA-PAM combined treatment, while root length was significantly reduced. Besides, the leaf catalase (CAT) and superoxide dismutase (SOD) enzyme activity, proline and chlorophyll content, increased after the treatment, while malondialdehyde (MDA) content decreased. The treatment also increased sucrase, urease, and alkaline protease activities in rhizosphere soil, while decreasing acid phosphatase and neutral phosphatase enzyme activities. ABA-PAM combined treatment enhanced the rhizosphere microbial community and forage drought resistance by altering the abundance of various dominant microorganisms in the rhizosphere soil. The relative abundances of Actinobacteria, Chloroflexi, and Acidobacteria decreased, while Proteobacteria, Firmicutes, and Ascomycota increased. Unlike the relative abundance of Gibberella that decreased significantly, Komagataeibacter, Lactobacillus, Pichia, and Dekkera were significantly increased. Single-factor collinearity network analysis revealed a close relationship between the different rhizosphere microbial communities of forage grass, after ABA-PAM treatment. This study implies that ABA-PAM combined treatment can improve the drought resistance of forages. Therefore, it provides a theoretical and practical basis for restoring drought-induced grassland degradation.
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Affiliation(s)
- Xue Tang
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Xueting Fei
- College of Life Sciences, Sichuan Normal University, Chengdu, China
- Leshan Haitang Experimental Middle School, Leshan, China
| | - Yining Sun
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Huanhuan Shao
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Jinyu Zhu
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Xinyi He
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Xiaoyan Wang
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Bin Yong
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Xiang Tao
- College of Life Sciences, Sichuan Normal University, Chengdu, China
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Yan C, Liu Z, Yuan Z, Shi X, Lock TR, Kallenbach RL. Aridity modifies the responses of plant stoichiometry to global warming and nitrogen deposition in semi-arid steppes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154807. [PMID: 35341862 DOI: 10.1016/j.scitotenv.2022.154807] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/19/2022] [Accepted: 03/20/2022] [Indexed: 06/14/2023]
Abstract
Global warming and nitrogen (N) deposition are known to unbalance the stoichiometry of carbon (C), N, and phosphorus (P) in terrestrial plants, but it is unclear how water availability regulates their effects along a natural aridity gradient. Here, we conducted manipulative experiments to determine the effects of experimental warming (WT) and N addition (NT) on plant stoichiometry in desert, typical, and meadow steppes with decreasing aridity. WT elevated air temperatures by 1.2-2.9 °C using open-top chambers. WT increased forb C:N ratio and thus its N use efficiency and competitiveness in desert steppes, whereas WT reduced forb C:N and C:P ratios in typical and meadow steppes. Plant N:P ratio, which reflects nutrient limitation, was reduced by WT in desert steppes but not for typical or meadow steppes. NT reduced plant C:N ratios and increased N:P ratios in all three steppes. NT reduced forb C:P ratios in desert and typical steppes, but it enhanced grass C:P ratio in meadow steppes, indicating an enhancement of P use efficiency and competitiveness of grasses in wet steppes. WT and NT had synergetic effects on grass C:N and C:P ratios in all three steppes, which helps to increase grasses' productivity. Under WT or NT, the changes in community C:N ratio were positively correlated with increasing aridity, indicating that aridity increases plants' N use efficiency. However, aridity negatively affected the changes in N:P ratios under NT but not WT, which suggests that aridity mitigates P limitation induced by N deposition. Our results imply that warming could shift the dominant functional group into forbs in dry steppes due to altered stoichiometry, whereas grasses become dominated plants in wet steppes under increasing N deposition. We suggest that global changes might break the stoichiometric balance of plants and water availability could strongly modify such processes in semi-arid steppes.
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Affiliation(s)
- Chuang Yan
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China; University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Geographical Sciences, Henan Academy of Sciences, Zhengzhou, Henan 450052, China
| | - Zunchi Liu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Zhiyou Yuan
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Xinrong Shi
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - T Ryan Lock
- Division of Plant Sciences and Technology, College of Agriculture, Food, and Natural Resources, University of Missouri, 108 Waters Hall, Columbia, MO 65211, USA
| | - Robert L Kallenbach
- Division of Plant Sciences and Technology, College of Agriculture, Food, and Natural Resources, University of Missouri, 108 Waters Hall, Columbia, MO 65211, USA
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10
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Liu S, He F, Kuzyakov Y, Xiao H, Hoang DTT, Pu S, Razavi BS. Nutrients in the rhizosphere: A meta-analysis of content, availability, and influencing factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 826:153908. [PMID: 35183641 DOI: 10.1016/j.scitotenv.2022.153908] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 06/14/2023]
Abstract
Nutrient deficiency in most terrestrial ecosystems constrains global primary productivity. Rhizosphere nutrient availability directly regulates plant growth and is influenced by many factors, including soil properties, plant characteristics and climate. A quantitatively comprehensive understanding of the role of these factors in modulating rhizosphere nutrient availability remains largely unknown. We reviewed 123 studies to assess nutrient availability in the rhizosphere compared to bulk soil depending on various factors. The increase in microbial nitrogen (N) content and N-cycling related enzyme activities in the rhizosphere led to a 10% increase in available N relative to bulk soil. The available phosphorus (P) in the rhizosphere decreased by 12% with a corresponding increase in phosphatase activities, indicating extreme demand and competition between plants and microorganisms for P. Greater organic carbon (C) content around taproots (+17%) confirmed their stronger ability to store more organic compounds than the fibrous roots. This corresponds to higher bacterial and fungal contents and slightly higher available nutrients in the rhizosphere of taproots. The maximal rhizosphere nutrient accumulation was common for low-fertile soils, which is confirmed by the negative correlation between most soil chemical properties and the effect sizes of available nutrients. Increases in rhizosphere bacterial and fungal population densities (205-254%) were much higher than microbial biomass increases (indicated as microbial C: +19%). Consequently, despite the higher microbial population densities in the rhizosphere, the biomass of individual microbial cells decreased, pointing on their younger age and faster turnover. This meta-analysis shows that, contrary to the common view, most nutrients are more available in the rhizosphere than in bulk soil because of higher microbial activities around roots.
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Affiliation(s)
- Shibin Liu
- College of Ecology and Environment, Chengdu University of Technology, 1# Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, PR China; State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, 1# Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, PR China
| | - Fakun He
- College of Earth Sciences, Chengdu University of Technology, 1# Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, PR China
| | - Yakov Kuzyakov
- Peoples Friendship University of Russia (RUDN University), Moscow, Russia; Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
| | - Huxuan Xiao
- College of Earth Sciences, Chengdu University of Technology, 1# Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, PR China
| | - Duyen Thi Thu Hoang
- Climate Change and Development Program, VNU Vietnam-Japan University, Vietnam National University, Hanoi, Viet Nam
| | - Shengyan Pu
- College of Ecology and Environment, Chengdu University of Technology, 1# Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, PR China; State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, 1# Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, PR China.
| | - Bahar S Razavi
- Department of Soil and Plant Microbiome, Institute of Phytopathology, Christian-Albrechts-University of Kiel, Kiel, Germany
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11
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Yu S, Sayer EJ, Li Z, Mo Q, Wang M, Li Y, Li Y, Xu G, Hu Z, Wang F. Delayed wet season increases soil net N mineralization in a seasonally dry tropical forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153314. [PMID: 35124037 DOI: 10.1016/j.scitotenv.2022.153314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/02/2022] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
Seasonal precipitation regime plays a vital role in regulating nutrient dynamics in seasonally dry tropical forests. Present evidence suggests that not only wet season precipitation is increasing in the tropics of South China, but also that the wet season is occurring later. However, it is unclear how nutrient dynamics will respond to the projected precipitation regime changes. We assessed the impacts of altered seasonal precipitation on soil net N mineralization in a secondary tropical forest. Since 2013, by reducing throughfall and/or irrigating experimental plots, we delayed the wet season by two months from April-September to June-November (DW treatment) or increased annual precipitation by 25% in July and August (WW treatment). We measured soil net N mineralization rates and assessed soil microbial communities in January, April, August and November in 2015 and 2017. We found that a wetter wet season did not significantly affect soil microbes or net N mineralization rates, even in the mid-wet season (August) when soil water content in the WW treatment increased significantly. By contrast, a delayed wet season enhanced soil microbial biomass and altered microbial community structure, resulting in a two-fold increase in net N mineralization rates relative to controls in the early dry season (November). Structural equation modeling showed that the changes in net N mineralization during the early dry season were associated with altered soil microbial communities, dissolved organic N, and litterfall, which were all affected by enhanced soil water content. Our findings suggest that a delayed wet season could have a greater impact on N dynamics than increased precipitation during the wet season. Changes in the seasonal timing of rainfall might therefore influence the functioning of seasonally dry tropical forests.
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Affiliation(s)
- Shiqin Yu
- School of Geography and Remote Sensing, Guangzhou University, Guangzhou 510006, PR China; Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Emma J Sayer
- Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, UK; Smithsonian Tropical Research Institute, Balboa, Ancon, Panama City, Panama
| | - Zhian Li
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Qifeng Mo
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, PR China
| | - Mei Wang
- School of Geographic Sciences, South China Normal University, Guangzhou 510631, China
| | - Yingwen Li
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China
| | - Yongxing Li
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China
| | - Guoliang Xu
- School of Geography and Remote Sensing, Guangzhou University, Guangzhou 510006, PR China
| | - Zhongmin Hu
- College of Ecology and Environment, Hainan University, Haikou 570228, China
| | - Faming Wang
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China.
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12
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Vizuete-Jaramillo E, Grahmann K, Mora Palomino L, Méndez-Barroso L, Robles-Morua A. Using ion-exchange resins to monitor nitrate fluxes in remote semiarid stream beds. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:376. [PMID: 35437732 DOI: 10.1007/s10661-022-10041-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Monitoring in remote areas can represent a real challenge in environmental studies. Numerous techniques have been developed over the last decades to monitor nutrients and other elements in different systems. However, not all of them are suitable for field applications, particularly when the locations are difficult to access or its accessibility depends on seasonal climate conditions. This study was aimed to test the applicability and efficiency of resin samplers and resin bags to monitor nitrates fluxes (NO3-N) in two small semi-arid catchments in Northwestern Mexico. Resin samplers were installed in the hyporheic zone below the river bed in order to monitor the vertical fluxes of NO3-N and remained there for 5 months (during the summer rains). Resin bags were anchored in rock outcrops upstream of the resin samplers before the onset of the summer rainfall season and replaced every 2 weeks during 4 months to capture pulses of NO3-N in ephemeral streams. NO3-N pulses in the stream are a potential source of NO3-N that can infiltrate into the soil. Results of the resin samplers found a difference of up to 12 kg ha-1 season-1 between the two catchments. The resin bags showed a higher accumulation of NO3-N in the catchment with lower vegetation cover (160.3 mg L-1 season-1) compared to the one with higher vegetation (67.8 mg L-1 season-1). Measured nitrate fluxes at both sites responded to rainfall pulses recorded during the monitoring period. Resin samplers and resin bags can be used together, to assess nutrient fluxes on the surface and in the soil and can be tested in any type of ecosystem. In this particular case, these methods demonstrated an efficient way of determining spatio-temporal nitrate fluxes in semi-arid ecosystems in remote areas that are difficult to access, monitor, and collect data.
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Affiliation(s)
- Efrain Vizuete-Jaramillo
- Departamento de Ciencias del Agua Y del Medio Ambiente, Instituto Tecnológico de Sonora (ITSON), Cd. Obregón, México
| | - Kathrin Grahmann
- Working Group "Resource-Efficient Cropping Systems", Research Area 2 "Landuse and Goverance", Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany
| | - Lucy Mora Palomino
- Departamento de Ciencias Ambientales Y del Suelo, Universidad Nacional Autónoma de México (UNAM), México, D.F., México
- Laboratorio Nacional de Geoquímica Y Mineralogía (LANGEM), México, D.F., México
| | - Luis Méndez-Barroso
- Departamento de Ciencias del Agua Y del Medio Ambiente, Instituto Tecnológico de Sonora (ITSON), Cd. Obregón, México
- Laboratorio Nacional de Resiliencia Costera (LANSREC), Sisal, Yucatán, México
| | - Agustín Robles-Morua
- Departamento de Ciencias del Agua Y del Medio Ambiente, Instituto Tecnológico de Sonora (ITSON), Cd. Obregón, México.
- Laboratorio Nacional de Geoquímica Y Mineralogía (LANGEM), México, D.F., México.
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13
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Adelizzi R, O'Brien EA, Hoellrich M, Rudgers JA, Mann M, Fernandes VMC, Darrouzet-Nardi A, Stricker E. Disturbance to biocrusts decreased cyanobacteria, N-fixer abundance, and grass leaf N but increased fungal abundance. Ecology 2022; 103:e3656. [PMID: 35132623 DOI: 10.1002/ecy.3656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/17/2021] [Accepted: 07/07/2021] [Indexed: 11/06/2022]
Abstract
Interactions between plants and soil microbes influence plant nutrient transformations, including nitrogen (N) fixation, nutrient mineralization, and resource exchanges through fungal networks. Physical disturbances to soils can disrupt soil microbes and associated processes that support plant and microbial productivity. In low resource drylands, biological soil crusts ("biocrusts") occupy surface soils and house key autotrophic and diazotrophic bacteria, non-vascular plants, or lichens. Interactions among biocrusts, plants, and fungal networks between them are hypothesized to drive carbon and nutrient dynamics; however, comparisons across ecosystems are needed to generalize how soil disturbances alter microbial communities and their contributions to N pools and transformations. To evaluate linkages among plants, fungi, and biocrusts, we disturbed all unvegetated surfaces with human foot trampling twice yearly in dry conditions from 2013-2019 in cyanobacteria-dominated biocrusts in Chihuahuan Desert grassland and shrubland ecosystems. After five years, disturbance decreased the abundances of cyanobacteria (especially Microcoleus steenstrupii clade) and N-fixers (Scytonema sp., and Schizothrix sp.) by >77% and chlorophyll a by up to 55%, but conversely, increased soil fungal abundance by 50% compared to controls. Responses of root-associated fungi differed between the two dominant plant species and ecosystem types, with a maximum of 80% more aseptate hyphae in disturbed than control plots. Although disturbance did not affect 15 N tracer transfer from biocrusts to the dominant grass, Bouteloua eriopoda, disturbance increased available soil N by 65% in the shrubland, and decreased leaf N of B. eriopoda up to 16%, suggesting that although rapid N transfer during peak production was not affected by disturbance, over the long term, plant nutrient content was disrupted. Altogether, the shrubland may be more resilient to detrimental changes due to disturbance than grassland, and these results demonstrate that disturbances to soil microbial communities have potential to cause substantial changes in N pools by reducing and reordering biocrust taxa.
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Affiliation(s)
- Rose Adelizzi
- Department of Biology, Washington College, 300 Washington Ave, Chestertown, Maryland, United States
| | - Elizabeth A O'Brien
- Department of Ecology and Evolutionary Biology, University of Michigan, 500 S State St, Ann Arbor, Michigan, United States
| | - Mikaela Hoellrich
- Department of Plant and Environmental Sciences, New Mexico State University, MSC 3Q, Las Cruces, New Mexico, United States
| | - Jennifer A Rudgers
- Department of Biology, University of New Mexico, MSC 03 2020, 1 University of New Mexico, Albuquerque, New Mexico, United States
| | - Michael Mann
- Department of Biology, University of New Mexico, MSC 03 2020, 1 University of New Mexico, Albuquerque, New Mexico, United States
| | - Vanessa Moreira Camara Fernandes
- Department of Biology, University of New Mexico, MSC 03 2020, 1 University of New Mexico, Albuquerque, New Mexico, United States
| | - Anthony Darrouzet-Nardi
- Department of Biological Sciences, University of Texas at El Paso, 500 W. University Ave., El Paso, Texas, United States
| | - Eva Stricker
- Department of Biology, University of New Mexico, MSC 03 2020, 1 University of New Mexico, Albuquerque, New Mexico, United States
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14
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Fang Z, Han X, Xie M, Jiao F. Spatial Distribution Patterns and Driving Factors of Plant Biomass and Leaf N, P Stoichiometry on the Loess Plateau of China. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112420. [PMID: 34834783 PMCID: PMC8625930 DOI: 10.3390/plants10112420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/30/2021] [Accepted: 11/04/2021] [Indexed: 05/22/2023]
Abstract
Understanding the geographic patterns and potential drivers of leaf stoichiometry and plant biomass is critical for modeling the biogeochemical cycling of ecosystems and to forecast the responses of ecosystems to global changes. Therefore, we studied the spatial patterns and potential drivers of leaf stoichiometry and herb biomass from 15 sites spanning from south to north along a 500 km latitudinal gradient of the Loess Plateau. We found that leaf N and P stoichiometry and the biomass of herb plants varied greatly on the Loess Plateau, showing spatial patterns, and there were significant differences among the four vegetation zones. With increasing latitude (decreasing mean annual temperature and decreasing mean precipitation), aboveground and belowground biomass displayed an opening downward parabolic trend, while the root-shoot ratio gradually decreased. Furthermore, there were significant linear relationships between the leaf nitrogen (N) and phosphorus (P) contents and latitude and climate (mean annual rainfall and mean annual temperature). However, the leaf N/P ratio showed no significant latitudinal or climatic trends. Redundancy analysis and stepwise regression analysis revealed herb biomass and leaf N and P contents were strongly related to environmental driving factors (slope, soil P content and latitude, altitude, mean annual rainfall and mean annual temperature). Compared with global scale results, herb plants on the Loess Plateau are characterized by relatively lower biomass, higher N content, lower P content and a higher N/P ratio, and vegetative growth may be more susceptible to P limitation. These findings indicated that the remarkable spatial distribution patterns of leaf N and P stoichiometry and herb biomass were jointly regulated by the climate, soil properties and topographic properties, providing new insights into potential vegetation restoration strategies.
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Affiliation(s)
- Zhao Fang
- Institute of Soil and Water Conservation, Northwest A&F University, Xi’an 712100, China; (Z.F.); (X.H.)
| | - Xiaoyu Han
- Institute of Soil and Water Conservation, Northwest A&F University, Xi’an 712100, China; (Z.F.); (X.H.)
| | - Mingyang Xie
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Xi’an 712100, China;
| | - Feng Jiao
- Institute of Soil and Water Conservation, Northwest A&F University, Xi’an 712100, China; (Z.F.); (X.H.)
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Xi’an 712100, China;
- Correspondence:
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15
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Yang Y, Xiao Y, Li C, Wang B, Gao Y, Zhou G. Nitrogen addition, rather than altered precipitation, stimulates nitrous oxide emissions in an alpine steppe. Ecol Evol 2021; 11:15153-15163. [PMID: 34765167 PMCID: PMC8571595 DOI: 10.1002/ece3.8196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/25/2022] Open
Abstract
Anthropogenic-driven global change, including changes in atmospheric nitrogen (N) deposition and precipitation patterns, is dramatically altering N cycling in soil. How long-term N deposition, precipitation changes, and their interaction influence nitrous oxide (N2O) emissions remains unknown, especially in the alpine steppes of the Qinghai-Tibetan Plateau (QTP). To fill this knowledge gap, a platform of N addition (10 g m-2 year-1) and altered precipitation (±50% precipitation) experiments was established in an alpine steppe of the QTP in 2013. Long-term N addition significantly increased N2O emissions. However, neither long-term alterations in precipitation nor the co-occurrence of N addition and altered precipitation significantly affected N2O emissions. These unexpected findings indicate that N2O emissions are particularly susceptible to N deposition in the alpine steppes. Our results further indicated that both biotic and abiotic properties had significant effects on N2O emissions. N2O emissions occurred mainly due to nitrification, which was dominated by ammonia-oxidizing bacteria, rather than ammonia-oxidizing archaea. Furthermore, the alterations in belowground biomass and soil temperature induced by N addition modulated N2O emissions. Overall, this study provides pivotal insights to aid the prediction of future responses of N2O emissions to long-term N deposition and precipitation changes in alpine ecosystems. The underlying microbial pathway and key predictors of N2O emissions identified in this study may also be used for future global-scale model studies.
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Affiliation(s)
- Yang Yang
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- University of Chinese Academy of ScienceBeijingChina
| | - Yuanming Xiao
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- University of Chinese Academy of ScienceBeijingChina
| | - Changbin Li
- College of Agriculture and Animal HusbandryQinghai UniversityXiningChina
| | - Bo Wang
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- University of Chinese Academy of ScienceBeijingChina
| | - Yongheng Gao
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- Institute of Mountain Hazards and EnvironmentChinese Academy of ScienceChengduChina
| | - Guoying Zhou
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- Key Laboratory of Tibetan Medicine ResearchChinese Academy of SciencesXiningChina
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16
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Li X, Yan Y, Fu L. Effects of Rainfall Manipulation on Ecosystem Respiration and Soil Respiration in an Alpine Steppe in Northern Tibet Plateau. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.708761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The response mechanism of ecosystem respiration (Re) and soil respiration (Rs) to different water conditions is of great significance for understanding the carbon cycle under future changes in the precipitation patterns. We used seven precipitation treatments to investigate the effects of precipitation on Re and Rs on a typical alpine steppe in Northern Tibet. Precipitation was captured and relocated to simulate the precipitation rates of −25, −50, −75, 0 (CK), +25, +50, and +75%. The soil moisture was influenced by all the precipitation treatments. There was a positive linear relationship between the soil moisture and Re, Rs in the study area during the experiment (July–October). Soil volumetric water content (VWC), absolute water content (AWC), soil temperature (ST), aboveground biomass (AGB), bulk density, soil total nitrogen (TN), and alkaline hydrolysis nitrogen (AHN) were the predictors of Re and Rs. The multiple linear regression analysis showed that ST and AWC could explain 90.6% of Rs, and ST, AWC, and AHN could explain 89.4% of Re. Ecosystem respiration was more sensitive to the increased precipitation (+29.5%) whereas Rs was more sensitive to the decreased precipitation (−23.8%). An appropriate increase in water (+25 and +50%) could improve the Re and Rs, but a greater increase (+75%) would not have a significant effect; it could have an effect even lower than those of the first two. Our study highlights the importance of increased precipitation and the disadvantage of decreased precipitation on Re and Rs in an arid region. The precipitation changes will lead to significant changes in the soil properties and AGB, and affect Re and Rs, to change the climate of the alpine steppe in Northern Tibet in the future. These findings contribute to our understanding of the regional patterns of environmental C exchange and soil C flux under the climate change scenarios and highlight the importance of water availability to the regulating ecosystem processes in semi-arid steppe ecosystems. In view of these findings, we urge future researchers to focus on manipulating the precipitation over longer time scales, seasonality, and incorporating more environmental factors to improve our ability to predict and model Re and Rs and feedback from climate change.
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17
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Li X, Zhang C, Zhang B, Wu D, Zhu D, Zhang W, Ye Q, Yan J, Fu J, Fang C, Ha D, Fu S. Nitrogen deposition and increased precipitation interact to affect fine root production and biomass in a temperate forest: Implications for carbon cycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:144497. [PMID: 33418324 DOI: 10.1016/j.scitotenv.2020.144497] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/06/2020] [Accepted: 12/09/2020] [Indexed: 06/12/2023]
Abstract
Fine roots connect belowground and aboveground systems and help regulate the carbon balance of terrestrial ecosystems by providing nutrients and water for plants. To evaluate the effects of atmospheric nitrogen (N) deposition and increased precipitation on fine root production and standing biomass in a temperate deciduous forest in central China, we conducted a 6-year experiment. From 2013 to 2018, we applied N (25 kg N ha-1 yr-1) and water (336 mm, 30% of the ambient annual precipitation) above the forest canopy, and we quantified fine root production and biomass in 2017 and 2018. At 0-10 cm soil depth, the statistical interaction between addition of N and water was not significant in terms of fine root production or biomass. At 0-10 cm soil depth, N addition significantly increased fine root production by 18.1%, but did not affect fine root biomass. Water addition significantly increased fine root production and biomass by 13.6 and 17.0%, respectively. Both N and water addition had significant direct positive effects on fine root production, and water addition had indirect positive effects on fine root biomass through decreasing soil NO3- concentration. At 10-30 cm soil depth, the statistical interaction between N addition and water addition was significant in terms of both fine root production and biomass, i.e., the positive effect of N addition was reduced by water addition, and vice versa. These findings indicate that fine roots and therefore belowground carbon storage may have complex responses to increases in atmospheric N deposition and changes in precipitation predicted for the future. The findings also suggest that results obtained from experiments that consider only one independent variable (e.g., N input or water input) and only one soil depth should be interpreted with caution.
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Affiliation(s)
- Xiaowei Li
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng 475004, China
| | - Chenlu Zhang
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng 475004, China.
| | - Beibei Zhang
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Di Wu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Dandan Zhu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Wei Zhang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Junhua Yan
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Juemin Fu
- Jigongshan National Nature Reserve, Xinyang 464039, China
| | | | - Denglong Ha
- Jigongshan National Nature Reserve, Xinyang 464039, China
| | - Shenglei Fu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng 475004, China
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18
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Guerrieri R, Correia M, Martín‐Forés I, Alfaro‐Sánchez R, Pino J, Hampe A, Valladares F, Espelta JM. Land‐use legacies influence tree water‐use efficiency and nitrogen availability in recently established European forests. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13787] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rossella Guerrieri
- CREAF Centre de Recerca Ecològica i Aplicacions ForestalsCatalonia Spain
- DISTAL University of Bologna Bologna Italy
| | - Marta Correia
- Centre for Functional Ecology Department of Life Sciences Calçada Martim de FreitasUniversity of Coimbra Coimbra Portugal
| | - Irene Martín‐Forés
- Department of Biogeography and Global Change National Museum of Natural SciencesSpanish Council for Scientific ResearchCSIC Madrid Spain
- School of Biological Sciences The University of Adelaide Adelaide SA Australia
| | - Raquel Alfaro‐Sánchez
- CREAF Centre de Recerca Ecològica i Aplicacions ForestalsCatalonia Spain
- Department of Biology Wilfrid Laurier University Waterloo ON Canada
| | - Joan Pino
- CREAF Centre de Recerca Ecològica i Aplicacions ForestalsCatalonia Spain
- Universitat Autònoma de Barcelona Catalonia Spain
| | - Arndt Hampe
- INRAEUniversity of BordeauxBIOGECO Cestas France
| | - Fernando Valladares
- Department of Biogeography and Global Change National Museum of Natural SciencesSpanish Council for Scientific ResearchCSIC Madrid Spain
| | - Josep Maria Espelta
- CREAF Centre de Recerca Ecològica i Aplicacions ForestalsCatalonia Spain
- Universitat Autònoma de Barcelona Catalonia Spain
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19
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The Influence of Climate, Soil Properties and Vegetation on Soil Nitrogen in Sloping Farmland. SUSTAINABILITY 2021. [DOI: 10.3390/su13031480] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Soil nitrogen in farmland ecosystems is affected by climate, soil physical and chemical properties and planting activities. To clarify the effects of these factors on soil nitrogen in sloping farmland quantitatively, the distribution of soil total nitrogen (TN) content, nitrate nitrogen (NO3-N) content and ammonium nitrogen (NH4-N) content at depth of 0–100 cm on 11 profiles of the Luanhe River Basin were analyzed. Meanwhile, soil physical and chemical properties, climatic factors and NDVI (Normalized Difference Vegetation Index) were used to construct a structural equation which reflected the influence mechanism of environmental factors on soil nitrogen concentration. The results showed that TN and NO3-N content decreased with the increase of soil depth in the Luanhe River Basin, while the variation of NH4-N content with soil depth was not obvious. Soil organic carbon (SOC) content, soil pH, soil area average particle size (SMD) and NDVI6 (NDVI of June) explained variation of TN content by 77.4%. SOC was the most important environmental factor contributing to the variation of TN content. NDVI5 (NDVI of May), annual average precipitation (MAP), soil pH and SOC explained 49.1% variation of NO3-N content. Among all environmental factors, only NDVI8 (NDVI of August) had significant correlation with soil NH4-N content, which explained the change of NH4-N content by 24.2%. The results showed that soil nitrogen content in the sloping farmland ecosystem was mainly affected by natural factors such as soil parent material and climate.
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Shishir S, Mollah TH, Tsuyuzaki S, Wada N. Predicting the probable impact of climate change on the distribution of threatened Shorea robusta forest in Purbachal, Bangladesh. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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21
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Ochoa‐Hueso R, Arca V, Delgado‐Baquerizo M, Hamonts K, Piñeiro J, Serrano‐Grijalva L, Shawyer J, Power SA. Links between soil microbial communities, functioning, and plant nutrition under altered rainfall in Australian grassland. ECOL MONOGR 2020. [DOI: 10.1002/ecm.1424] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Raúl Ochoa‐Hueso
- Department of Biology IVAGROUniversity of Cádiz Campus de Excelencia Internacional Agroalimentario (ceiA3), Campus del Rio San Pedro Puerto Real Cádiz 11510 Spain
- Hawkesbury Institute for the EnvironmentWestern Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
| | - Valentina Arca
- Hawkesbury Institute for the EnvironmentWestern Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
| | - Manuel Delgado‐Baquerizo
- Hawkesbury Institute for the EnvironmentWestern Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
- Departamento de Sistemas Físicos, Químicos y Naturales Universidad Pablo de Olavide Sevilla 41013 Spain
| | - Kelly Hamonts
- Hawkesbury Institute for the EnvironmentWestern Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
| | - Juan Piñeiro
- Hawkesbury Institute for the EnvironmentWestern Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
- Division of Plant and Soil Sciences West Virginia University Morgantown West Virginia 26506 USA
| | - Lilia Serrano‐Grijalva
- Department of Biology IVAGROUniversity of Cádiz Campus de Excelencia Internacional Agroalimentario (ceiA3), Campus del Rio San Pedro Puerto Real Cádiz 11510 Spain
- Hawkesbury Institute for the EnvironmentWestern Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
| | - Julien Shawyer
- Hawkesbury Institute for the EnvironmentWestern Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
| | - Sally A. Power
- Hawkesbury Institute for the EnvironmentWestern Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
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22
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Zhang H, Shi L, Lu H, Shao Y, Liu S, Fu S. Drought promotes soil phosphorus transformation and reduces phosphorus bioavailability in a temperate forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 732:139295. [PMID: 32438146 DOI: 10.1016/j.scitotenv.2020.139295] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 05/02/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
Drought can substantially alter ecosystem functions, especially biogeochemical cycles of key nutrients. As an essential but often limiting nutrient, P plays a central role in critical ecosystem processes (i.e. primary productivity). However, little is known about how drought can affect the soil phosphorus (P) cycle and its bioavailability in forest ecosystems. Here, we conducted a four-year field drought experiment using throughfall reduction approach to examine how drought can alter soil P dynamics and bioavailability in a warm temperate forest. We found that the P held in calcium phosphate was significantly decreased under drought, which was accompanied by the increases of inorganic and organic P bound with secondary minerals (Fe/Al oxides). These drought-induced P transformations can be well explained by the soil pH. The significant decline in soil pH under drought can drive the solubilization of P held in calcium phosphate. Our study further showed that drought directly decreased soil P bioavailability and altered the potential mechanisms of the replenishment of inorganic P into the soil solution. The potential of the inorganic P release driven by protons was reduced, while inorganic P release potentials driven by enzyme and organic acid were increased under drought. Therefore, our results strongly suggested that drought can significantly alter the soil P biogeochemical cycles and change the biological mechanisms underlying P bioavailability.
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Affiliation(s)
- Hongzhi Zhang
- Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Jinming Avenue, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng, Jinming Avenue, Henan 475004, China
| | - Leilei Shi
- Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Jinming Avenue, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng, Jinming Avenue, Henan 475004, China
| | - Haibo Lu
- School of Atmospheric Sciences, Sun Yat-sen University, No. 135, Xingang Xi Road, Guangzhou 510275, China; Key Laboratory of Forest Ecology and Environment, China's State Forestry Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, No. 2 Dongxiaofu, Haidian District, Beijing 100091, China.
| | - Yuanhu Shao
- Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Jinming Avenue, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng, Jinming Avenue, Henan 475004, China.
| | - Shirong Liu
- Key Laboratory of Forest Ecology and Environment, China's State Forestry Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, No. 2 Dongxiaofu, Haidian District, Beijing 100091, China.
| | - Shenglei Fu
- Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Jinming Avenue, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng, Jinming Avenue, Henan 475004, China.
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23
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Eaton WD, McGee KM, Alderfer K, Jimenez AR, Hajibabaei M. Increase in abundance and decrease in richness of soil microbes following Hurricane Otto in three primary forest types in the Northern Zone of Costa Rica. PLoS One 2020; 15:e0231187. [PMID: 32730267 PMCID: PMC7392270 DOI: 10.1371/journal.pone.0231187] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/07/2020] [Indexed: 11/26/2022] Open
Abstract
Little is known of how hurricane-induced deposition of canopy material onto tropical forest floors influences the soil microbial communities involved in decomposition of these materials. In this study, to identify how soil bacterial and fungal communities might change after a hurricane, and their possible roles in the C and N cycles, soils were collected from five 2000 m2 permanent plots in Lowland, Upland and Riparian primary forests in Costa Rica 3 months before and 7 months after Hurricane Otto damaged the forests. The soil Water, inorganic N and Biomass C increased and total organic C decreased Post-Hurricane, all of which best predicted the changes in the Post-Hurricane soil microbial communities. Post-Hurricane soils from all forest types showed significant changes in community composition of total bacteria, total fungi, and five functional groups of microbes (i.e., degrading/lignin degrading, NH4+-producing, and ammonium oxidizing bacteria, and the complex C degrading/wood rot/lignin degrading and ectomycorrhizal fungi), along with a decrease in richness in genera of all groups. As well, the mean proportion of DNA sequences (MPS) of all five functional groups increased. There were also significant changes in the MPS values of 7 different fungal and 7 different bacterial genera that were part of these functional groups. This is the first evidence that hurricane-induced deposition of canopy material is stimulating changes in the soil microbial communities after the hurricane, involving changes in specific taxonomic and functional group genera, and reduction in the community richness while selecting for dominant genera possibly better suited to process the canopy material. These changes may represent examples of taxonomic switching of functionally redundant microbial genera in response to dramatic changes in resource input. It is possible that differences in these microbial communities and genera may serve as indicators of disturbed and recovering regional soil ecosystems, and should be evaluated in the future.
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Affiliation(s)
- William D. Eaton
- Biology Department, Pace University, New York, NY, United States of America
- * E-mail:
| | - Katie M. McGee
- Department of Integrative Biology, Biodiversity Institute of Ontario, University of Guelph, Guelph, ON, Canada
| | - Kiley Alderfer
- Biology Department, Pace University, New York, NY, United States of America
| | | | - Mehrdad Hajibabaei
- Department of Integrative Biology, Biodiversity Institute of Ontario, University of Guelph, Guelph, ON, Canada
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24
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Batke SP, Yiotis C, Elliott-Kingston C, Holohan A, McElwain J. Plant responses to decadal scale increments in atmospheric CO 2 concentration: comparing two stomatal conductance sampling methods. PLANTA 2020; 251:52. [PMID: 31950281 PMCID: PMC6965045 DOI: 10.1007/s00425-020-03343-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/08/2020] [Indexed: 05/14/2023]
Abstract
MAIN CONCLUSION Our study demonstrated that the species respond non-linearly to increases in CO2 concentration when exposed to decadal changes in CO2, representing the year 1987, 2025, 2051, and 2070, respectively. There are several lines of evidence suggesting that the vast majority of C3 plants respond to elevated atmospheric CO2 by decreasing their stomatal conductance (gs). However, in the majority of CO2 enrichment studies, the response to elevated CO2 are tested between plants grown under ambient (380-420 ppm) and high (538-680 ppm) CO2 concentrations and measured usually at single time points in a diurnal cycle. We investigated gs responses to simulated decadal increments in CO2 predicted over the next 4 decades and tested how measurements of gs may differ when two alternative sampling methods are employed (infrared gas analyzer [IRGA] vs. leaf porometer). We exposed Populus tremula, Popolus tremuloides and Sambucus racemosa to four different CO2 concentrations over 126 days in experimental growth chambers at 350, 420, 490 and 560 ppm CO2; representing the years 1987, 2025, 2051, and 2070, respectively (RCP4.5 scenario). Our study demonstrated that the species respond non-linearly to increases in CO2 concentration when exposed to decadal changes in CO2. Under natural conditions, maximum operational gs is often reached in the late morning to early afternoon, with a mid-day depression around noon. However, we showed that the daily maximum gs can, in some species, shift later into the day when plants are exposed to only small increases (70 ppm) in CO2. A non-linear decreases in gs and a shifting diurnal stomatal behavior under elevated CO2, could affect the long-term daily water and carbon budget of many plants in the future, and therefore alter soil-plant-atmospheric processes.
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Affiliation(s)
- Sven Peter Batke
- Biology Department, Edge Hill University, St. Helen's Road, Ormskirk, L39 4QP, UK.
| | - Charilaos Yiotis
- Botany Department, Trinity College Dublin, College Green, Dublin 2, Dublin, Ireland
| | - Caroline Elliott-Kingston
- School of Agriculture and Food Science, University College Dublin, Stillorgan Road, Belfield, Dublin 4, Dublin, Ireland
| | - Aidan Holohan
- School Biology and Environmental Science, University College Dublin, Stillorgan Road, Belfield, Dublin 4, Dublin, Ireland
| | - Jennifer McElwain
- Botany Department, Trinity College Dublin, College Green, Dublin 2, Dublin, Ireland
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25
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Mapping of Soil Total Nitrogen Content in the Middle Reaches of the Heihe River Basin in China Using Multi-Source Remote Sensing-Derived Variables. REMOTE SENSING 2019. [DOI: 10.3390/rs11242934] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Soil total nitrogen (STN) is an important indicator of soil quality and plays a key role in global nitrogen cycling. Accurate prediction of STN content is essential for the sustainable use of soil resources. Synthetic aperture radar (SAR) provides a promising source of data for soil monitoring because of its all-weather, all-day monitoring, but it has rarely been used for STN mapping. In this study, we explored the potential of multi-temporal Sentinel-1 data to predict STN by evaluating and comparing the performance of boosted regression trees (BRTs), random forest (RF), and support vector machine (SVM) models in STN mapping in the middle reaches of the Heihe River Basin in northwestern China. Fifteen predictor variables were used to construct models, including land use/land cover, multi-source remote sensing-derived variables, and topographic and climatic variables. We evaluated the prediction accuracy of the models based on a cross-validation procedure. Results showed that tree-based models (RF and BRT) outperformed SVM. Compared to the model that only used optical data, the addition of multi-temporal Sentinel-1A data using the BRT method improved the root mean square error (RMSE) and the mean absolute error (MAE) by 17.2% and 17.4%, respectively. Furthermore, the combination of all predictor variables using the BRT model had the best predictive performance, explaining 57% of the variation in STN, with the highest R2 (0.57) value and the lowest RMSE (0.24) and MAE (0.18) values. Remote sensing variables were the most important environmental variables for STN mapping, with 59% and 50% relative importance in the RF and BRT models, respectively. Our results show the potential of using multi-temporal Sentinel-1 data to predict STN, broadening the data source for future digital soil mapping. In addition, we propose that the SVM, RF, and BRT models should be calibrated and evaluated to obtain the best results for STN content mapping in similar landscapes.
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26
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Grossiord C, Gessler A, Reed SC, Borrego I, Collins AD, Dickman LT, Ryan M, Schönbeck L, Sevanto S, Vilagrosa A, McDowell NG. Reductions in tree performance during hotter droughts are mitigated by shifts in nitrogen cycling. PLANT, CELL & ENVIRONMENT 2018; 41:2627-2637. [PMID: 29974965 DOI: 10.1111/pce.13389] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 05/16/2023]
Abstract
Climate warming should result in hotter droughts of unprecedented severity in this century. Such droughts have been linked with massive tree mortality, and data suggest that warming interacts with drought to aggravate plant performance. Yet how forests will respond to hotter droughts remains unclear, as does the suite of mechanisms trees use to deal with hot droughts. We used an ecosystem-scale manipulation of precipitation and temperature on piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees to investigate nitrogen (N) cycling-induced mitigation processes related to hotter droughts. We found that while negative impacts on plant carbon and water balance are manifest after prolonged drought, performance reductions were not amplified by warmer temperatures. Rather, increased temperatures for 5 years stimulated soil N cycling under piñon trees and modified tree N allocation for both species, resulting in mitigation of hotter drought impacts on tree water and carbon functions. These findings suggest that adjustments in N cycling are likely after multi-year warming conditions and that such changes may buffer reductions in tree performance during hotter droughts. The results highlight our incomplete understanding of trees' ability to acclimate to climate change, raising fundamental questions about the resistance potential of forests to long-term, compound climatic stresses.
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Affiliation(s)
- Charlotte Grossiord
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Arthur Gessler
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Sasha C Reed
- US Geological Survey, Southwest Biological Science Center, Moab, UT
| | - Isaac Borrego
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- US Geological Survey, Southwest Biological Science Center, Moab, UT
| | - Adam D Collins
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Lee T Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Max Ryan
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Alberto Vilagrosa
- Fundación CEAM, Joint Research Unit University of Alicante - CEAM, University of Alicante, Alicante, Spain
| | - Nate G McDowell
- Earth Systems Science Division, Pacific Northwest National Laboratory, Richland, WA, USA
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27
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Asbjornsen H, Campbell JL, Jennings KA, Vadeboncoeur MA, McIntire C, Templer PH, Phillips RP, Bauerle TL, Dietze MC, Frey SD, Groffman PM, Guerrieri R, Hanson PJ, Kelsey EP, Knapp AK, McDowell NG, Meir P, Novick KA, Ollinger SV, Pockman WT, Schaberg PG, Wullschleger SD, Smith MD, Rustad LE. Guidelines and considerations for designing field experiments simulating precipitation extremes in forest ecosystems. Methods Ecol Evol 2018. [DOI: 10.1111/2041-210x.13094] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Heidi Asbjornsen
- Department of Natural Resources and the EnvironmentUniversity of New Hampshire Durham New Hampshire
- Earth Systems Research CenterInstitute for Earth, Oceans, and SpaceUniversity of New Hampshire Durham New Hampshire
| | - John L. Campbell
- Northern Research StationUSDA Forest Service Durham New Hampshire
| | - Katie A. Jennings
- Department of Natural Resources and the EnvironmentUniversity of New Hampshire Durham New Hampshire
- Earth Systems Research CenterInstitute for Earth, Oceans, and SpaceUniversity of New Hampshire Durham New Hampshire
| | - Matthew A. Vadeboncoeur
- Earth Systems Research CenterInstitute for Earth, Oceans, and SpaceUniversity of New Hampshire Durham New Hampshire
| | - Cameron McIntire
- Department of Natural Resources and the EnvironmentUniversity of New Hampshire Durham New Hampshire
| | | | | | - Taryn L. Bauerle
- School of Integrative Plant ScienceCornell University Ithaca New York
| | - Michael C. Dietze
- Department of Earth and EnvironmentBoston University Boston Massachusetts
| | - Serita D. Frey
- Department of Natural Resources and the EnvironmentUniversity of New Hampshire Durham New Hampshire
| | - Peter M. Groffman
- Department of Earth and Environmental SciencesAdvanced Science Research Center at the Graduate Center of the City University of New York and Brooklyn College New York New York
| | - Rosella Guerrieri
- Centre for Ecological Research and Forestry Applications (CREAF)Universidad Autonoma de Barcelona Barcelona Spain
| | - Paul J. Hanson
- Environmental Sciences DivisionOak Ridge National Laboratory Oak Ridge Tennessee
| | - Eric P. Kelsey
- Department of Atmospheric Science and ChemistryPlymouth State University Plymouth New Hampshire
- Mount Washington Observatory North Conway New Hampshire
| | - Alan K. Knapp
- Department of Biology and Graduate Degree Program in EcologyColorado State University Fort Collins Colorado
| | | | - Patrick Meir
- Research School of BiologyAustralian National University Canberra ACT Australia
- School of GeosciencesUniversity of Edinburgh Edinburgh UK
| | - Kimberly A. Novick
- School of Public and Environmental AffairsIndiana University Bloomington Indiana
| | - Scott V. Ollinger
- Department of Natural Resources and the EnvironmentUniversity of New Hampshire Durham New Hampshire
| | - Will T. Pockman
- Department of BiologyUniversity of New Mexico Albuquerque New Mexico
| | | | - Stan D. Wullschleger
- Environmental Sciences DivisionOak Ridge National Laboratory Oak Ridge Tennessee
| | - Melinda D. Smith
- Department of Biology and Graduate Degree Program in EcologyColorado State University Fort Collins Colorado
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28
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Shi L, Zhang H, Liu T, Mao P, Zhang W, Shao Y, Fu S. An increase in precipitation exacerbates negative effects of nitrogen deposition on soil cations and soil microbial communities in a temperate forest. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 235:293-301. [PMID: 29294455 DOI: 10.1016/j.envpol.2017.12.083] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 12/19/2017] [Accepted: 12/22/2017] [Indexed: 05/28/2023]
Abstract
World soils are subjected to a number of anthropogenic global change factors. Although many previous studies contributed to understand how single global change factors affect soil properties, there have been few studies aimed at understanding how two naturally co-occurring global change drivers, nitrogen (N) deposition and increased precipitation, affect critical soil properties. In addition, most atmospheric N deposition and precipitation increase studies have been simulated by directly adding N solution or water to the forest floor, and thus largely neglect some key canopy processes in natural conditions. These previous studies, therefore, may not realistically simulate natural atmospheric N deposition and precipitation increase in forest ecosystems. In a field experiment, we used novel canopy applications to investigate the effects of N deposition, increased precipitation, and their combination on soil chemical properties and the microbial community in a temperate deciduous forest. We found that both soil chemistry and microorganisms were sensitive to these global change factors, especially when they were simultaneously applied. These effects were evident within 2 years of treatment initiation. Canopy N deposition immediately accelerated soil acidification, base cation depletion, and toxic metal accumulation. Although increased precipitation only promoted base cation leaching, this exacerbated the effects of N deposition. Increased precipitation decreased soil fungal biomass, possible due to wetting/re-drying stress or to the depletion of Na. When N deposition and increased precipitation occurred together, soil gram-negative bacteria decreased significantly, and the community structure of soil bacteria was altered. The reduction of gram-negative bacterial biomass was closely linked to the accumulation of the toxic metals Al and Fe. These results suggested that short-term responses in soil cations following N deposition and increased precipitation could change microbial biomass and community structure.
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Affiliation(s)
- Leilei Shi
- Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Jinming Avenue, Kaifeng 475004, China.
| | - Hongzhi Zhang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China.
| | - Tao Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China; University of the Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan District, Beijing 100049, China.
| | - Peng Mao
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China; University of the Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan District, Beijing 100049, China.
| | - Weixin Zhang
- Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Jinming Avenue, Kaifeng 475004, China.
| | - Yuanhu Shao
- Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Jinming Avenue, Kaifeng 475004, China.
| | - Shenglei Fu
- Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Jinming Avenue, Kaifeng 475004, China.
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29
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Responses of Tree Transpiration and Growth to Seasonal Rainfall Redistribution in a Subtropical Evergreen Broad-Leaved Forest. Ecosystems 2017. [DOI: 10.1007/s10021-017-0185-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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30
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Gessler A, Schaub M, McDowell NG. The role of nutrients in drought-induced tree mortality and recovery. THE NEW PHYTOLOGIST 2017; 214:513-520. [PMID: 27891619 DOI: 10.1111/nph.14340] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 10/08/2016] [Indexed: 05/21/2023]
Abstract
Contents 513 I. 513 II. 514 III. 517 518 References 518 SUMMARY: Global forests are experiencing rising temperatures and more severe droughts, with consistently dire forecasts for negative future impacts. Current research on the physiological mechanisms underlying drought impacts is focused on the water- and carbon-associated mechanisms. The role of nutrients is notably missing from this research agenda. Here, we investigate what role, if any, forest nutrition plays for survival and recovery of forests during and after drought. High nutrient availability may play a detrimental role in drought survival due to preferential biomass allocation aboveground that (1) predispose plants to hydraulic constraints limiting photosynthesis and promoting hydraulic failure, (2) increases carbon costs during periods of carbon starvation, and (3) promote biotic attack due to low tissue carbon: nitrogen (C : N). When nutrient uptake occurs during drought, high nutrient availability can increase water use efficiency thus minimizing negative feedbacks between carbon and nutrient balance. Nutrients are released after drought ceases, which might promote faster recovery but the temporal dynamics of microbial immobilization and nutrient leaching have a significant impact on nutrient availability. We provide a framework for understanding nutrient impacts on drought survival that allows a more complete analysis of forest ecosystem responses.
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Affiliation(s)
- Arthur Gessler
- Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Marcus Schaub
- Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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31
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Zabaloy MC, Carné I, Viassolo R, Gómez MA, Gomez E. Soil ecotoxicity assessment of glyphosate use under field conditions: microbial activity and community structure of Eubacteria and ammonia-oxidising bacteria. PEST MANAGEMENT SCIENCE 2016; 72:684-91. [PMID: 25960311 DOI: 10.1002/ps.4037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/03/2015] [Accepted: 05/04/2015] [Indexed: 05/20/2023]
Abstract
BACKGROUND A plot-scale experiment was conducted to assess the impact of field application rates of glyphosate on soil microbial communities by taking measurements of microbial activity (in terms of substrate-induced respiration and enzyme activity) in parallel with culture-independent approaches to assessing both bacterial abundance and diversity. Two rates of glyphosate, alone or in a mixture with 2,4-dichlorophenoxyacetic acid, were applied directly onto the soil surface, simulating normal use in chemical fallow in no-till systems. RESULTS No consistent rate-dependent responses were observed in the microbial activity parameters investigated in the field plots that were exposed to glyphosate. Denaturant gradient gel electrophoresis (DGGE) of the overall bacterial community (Eubacteria) and ammonia-oxidising bacteria (AOB) revealed no effects of the high rate of glyphosate on the structure of the communities in comparison with the control. No treatment effects were observed on the abundance of Eubacteria shortly after treatment in 2010, while a small but significant difference between the high rate and the control was detected in the first sampling in 2011. The abundance of AOB was relatively low during the study, and treatment effects were undetectable. CONCLUSIONS The absence of negative effects on soil microbial communities in this study suggests that glyphosate use at recommended rates poses low risk to the microbiota.
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Affiliation(s)
- María C Zabaloy
- Microbial Ecology Laboratory, Departamento de Agronomía (UNS), Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Bahía Blanca, Argentina
| | - Ignacio Carné
- Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, 2125, Zavalla, Argentina
| | - Rodrigo Viassolo
- Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, 2125, Zavalla, Argentina
| | - Marisa A Gómez
- Microbial Ecology Laboratory, Departamento de Agronomía (UNS), Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Bahía Blanca, Argentina
| | - Elena Gomez
- Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, 2125, Zavalla, Argentina
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Plant hydraulic responses to long-term dry season nitrogen deposition alter drought tolerance in a Mediterranean-type ecosystem. Oecologia 2016; 181:721-31. [DOI: 10.1007/s00442-016-3609-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 03/08/2016] [Indexed: 10/22/2022]
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Lu X, Yan Y, Sun J, Zhang X, Chen Y, Wang X, Cheng G. Carbon, nitrogen, and phosphorus storage in alpine grassland ecosystems of Tibet: effects of grazing exclusion. Ecol Evol 2015; 5:4492-504. [PMID: 26664694 PMCID: PMC4667823 DOI: 10.1002/ece3.1732] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 08/05/2015] [Accepted: 08/22/2015] [Indexed: 11/30/2022] Open
Abstract
In recent decades, alpine grasslands have been seriously degraded on the Tibetan Plateau and grazing exclusion by fencing has been widely adopted to restore degraded grasslands since 2004. To elucidate how alpine grasslands carbon (C), nitrogen (N), and phosphorus (P) storage responds to this management strategy, three types of alpine grassland in nine counties in Tibet were selected to investigate C, N, and P storage in the environment by comparing free grazing (FG) and grazing exclusion (GE) treatments, which had run for 6–8 years. The results revealed that there were no significant differences in total ecosystem C, N, and P storage, as well as the C, N, and P stored in both total biomass and soil (0–30 cm) fractions between FG and GE grasslands. However, precipitation played a key role in controlling C, N, and P storage and distribution. With grazing exclusion, C and N stored in aboveground biomass significantly increased by 5.7 g m−2 and 0.1 g m−2, respectively, whereas the C and P stored in the soil surface layer (0–15 cm) significantly decreased by 862.9 g m−2 and 13.6 g m−2, respectively. Furthermore, the storage of the aboveground biomass C, N, and P was positively correlated with vegetation cover and negatively correlated with the biodiversity index, including Pielou evenness index, Shannon–Wiener diversity index, and Simpson dominance index. The storage of soil surface layer C, N, and P was positively correlated with soil silt content and negatively correlated with soil sand content. Our results demonstrated that grazing exclusion had no impact on total C, N, and P storage, as well as C, N, and P in both total biomass and soil (0–30 cm) fractions in the alpine grassland ecosystem. However, grazing exclusion could result in increased aboveground biomass C and N pools and decreased soil surface layer (0–15 cm) C and P pools.
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Affiliation(s)
- Xuyang Lu
- Key Laboratory of Mountain Surface Processes and Ecological Regulation Chinese Academy of Sciences Chengdu 610041 China ; Xainza Alpine Steppe and Wetland Ecosystem Observation and Experiment Station Chinese Academy of Sciences Xainza 853100 China
| | - Yan Yan
- Key Laboratory of Mountain Surface Processes and Ecological Regulation Chinese Academy of Sciences Chengdu 610041 China
| | - Jian Sun
- Key Laboratory of Ecosystem Network Observation and Modeling Chinese Academy of Sciences Beijing 100101 China
| | - Xiaoke Zhang
- Key Laboratory of Mountain Surface Processes and Ecological Regulation Chinese Academy of Sciences Chengdu 610041 China
| | - Youchao Chen
- Key Laboratory of Mountain Surface Processes and Ecological Regulation Chinese Academy of Sciences Chengdu 610041 China
| | - Xiaodan Wang
- Key Laboratory of Mountain Surface Processes and Ecological Regulation Chinese Academy of Sciences Chengdu 610041 China ; Xainza Alpine Steppe and Wetland Ecosystem Observation and Experiment Station Chinese Academy of Sciences Xainza 853100 China
| | - Genwei Cheng
- Key Laboratory of Mountain Surface Processes and Ecological Regulation Chinese Academy of Sciences Chengdu 610041 China
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Nielsen UN, Ball BA. Impacts of altered precipitation regimes on soil communities and biogeochemistry in arid and semi-arid ecosystems. GLOBAL CHANGE BIOLOGY 2015; 21:1407-21. [PMID: 25363193 DOI: 10.1111/gcb.12789] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 09/28/2014] [Indexed: 05/19/2023]
Abstract
Altered precipitation patterns resulting from climate change will have particularly significant consequences in water-limited ecosystems, such as arid to semi-arid ecosystems, where discontinuous inputs of water control biological processes. Given that these ecosystems cover more than a third of Earth's terrestrial surface, it is important to understand how they respond to such alterations. Altered water availability may impact both aboveground and belowground communities and the interactions between these, with potential impacts on ecosystem functioning; however, most studies to date have focused exclusively on vegetation responses to altered precipitation regimes. To synthesize our understanding of potential climate change impacts on dryland ecosystems, we present here a review of current literature that reports the effects of precipitation events and altered precipitation regimes on belowground biota and biogeochemical cycling. Increased precipitation generally increases microbial biomass and fungal:bacterial ratio. Few studies report responses to reduced precipitation but the effects likely counter those of increased precipitation. Altered precipitation regimes have also been found to alter microbial community composition but broader generalizations are difficult to make. Changes in event size and frequency influences invertebrate activity and density with cascading impacts on the soil food web, which will likely impact carbon and nutrient pools. The long-term implications for biogeochemical cycling are inconclusive but several studies suggest that increased aridity may cause decoupling of carbon and nutrient cycling. We propose a new conceptual framework that incorporates hierarchical biotic responses to individual precipitation events more explicitly, including moderation of microbial activity and biomass by invertebrate grazing, and use this framework to make some predictions on impacts of altered precipitation regimes in terms of event size and frequency as well as mean annual precipitation. While our understanding of dryland ecosystems is improving, there is still a great need for longer term in situ manipulations of precipitation regime to test our model.
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Affiliation(s)
- Uffe N Nielsen
- Hawkesbury Institute for the Environment and School of Science and Health, University of Western Sydney, Penrith, NSW 2751, Australia
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