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Liu D, Song X, Hu J, Liu Y, Wang C, Henkin Z. Precipitation affects soil nitrogen fixation by regulating active diazotrophs and nitrate nitrogen in an alpine grassland of Qinghai-Tibetan Plateau. Sci Total Environ 2024; 919:170648. [PMID: 38336078 DOI: 10.1016/j.scitotenv.2024.170648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 01/27/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024]
Abstract
Soil asymbiotic nitrogen (N) fixation provides a critical N source to support plant growth in alpine grasslands, and precipitation change is expected to lead to shifts in soil asymbiotic N fixation. However, large gaps remain in understanding the response of soil asymbiotic N fixation to precipitation gradients. Here we simulated five precipitation gradients (10 % (0.1P), 50 % (0.5P), 70 % (0.7P), 100 % (1.0P) and 150 % (1.5P) of the natural precipitation) in an alpine grassland of Qinghai-Tibetan Plateau and examined the soil nitrogenase activity and N fixation rate for each gradient. Quantitative PCR and high-throughput sequencing were used to measure the abundance and community composition of the soil nifH DNA (total diazotrophs) and nifH RNA reverse transcription (active diazotrophs) gene. Our results showed that the soil diazotrophic abundance, diversity and nifH gene expression rate peaked under the 0.5P. Soil nitrogenase activity and N fixation rate varied in the range 0.032-0.073 nmol·C2H4·g-1·h-1 and 0.008-0.022 nmol·N2·g-1·h-1 respectively, being highest under the 0.5P. The 50 % precipitation reduction enhanced the gene expression rates of Azospirillum and Halorhodospira which were likely responsible for the high N fixation potential. The 0.5P treatment also possessed a larger and more complex active diazotrophic network than the other treatments, which facilitated the resistance of diazotrophic community to environmental stress and thus maintained a high N fixation potential. The active diazotrophic abundance had the largest positive effect on soil N fixation, while nitrate nitrogen had the largest negative effect. Together, our study suggested that appropriate precipitation reduction can enhance soil N fixation through promoting the abundance of the soil active diazotrophs and decreasing soil nitrate nitrogen, and soil active diazotrophs and nitrate nitrogen should be considered in predicting soil N inputs in the alpine grassland of Qinghai-Tibetan Plateau under precipitation change.
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Affiliation(s)
- Dan Liu
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China.
| | - Xiaoyan Song
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
| | - Jian Hu
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
| | - Yang Liu
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
| | - Changting Wang
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
| | - Zalmen Henkin
- Department of Natural Resources, Newe Ya'ar Research Center, Agricultural Research Organization, Volcani Institute, Israel
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Hao J, Feng Y, Wang X, Yu Q, Zhang F, Yang G, Ren G, Han X, Wang X, Ren C. Soil microbial nitrogen-cycling gene abundances in response to crop diversification: A meta-analysis. Sci Total Environ 2022; 838:156621. [PMID: 35691356 DOI: 10.1016/j.scitotenv.2022.156621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/26/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Single planting structure has a significant impact on the maintenance of nitrogen in managed ecosystems. Although the effect of crop diversity on soil nitrogen-cycling microbes is mainly related to the influence of environmental factors, there is a lack of quantitative research. This study aims to determine the effect of diversified cropping mode on the abundance of functional genes in the soil nitrogen cycle based on the quantitative integration of a meta-analysis database containing 189 observation data pairs. The results show that the soil nifH (nitrogenase coding gene), nirS and nirK (nitrite reductase coding gene), and narG (nitrate reductase coding gene) abundances are positively affected by the diversity of plant species, whereas the amoA (ammonia monooxygenase coding gene) and nosZ (nitrous oxide reductase coding gene) show no response. Diversification duration and ecosystem type are important factors that regulate soil nitrogen fixation and nitrification gene abundances. Denitrification genes are mainly affected by categorical variables such as the planting pattern, soil layer, application species, duration, and soil texture. Among them, the long-term continuous diversification is mainly manifested in the reduction of soil nifH and increase of nirK abundances. Soil organic carbon and nitrogen linearly affect the responses of nifH, amoA, nirS, and nirK. Therefore, to maintain the soil ecological function, diversity of planting patterns needs to be applied flexibly by regulating the abundance of nitrogen-cycling genes. Our study draws conclusions in order to provide theoretical references for the sustainability of nitrogen and improvement of management measures in the process of terrestrial managed ecosystem diversification.
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Affiliation(s)
- Jiaqi Hao
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
| | - Yongzhong Feng
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China.
| | - Xing Wang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
| | - Qi Yu
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
| | - Fu Zhang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
| | - Gaihe Yang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
| | - Guangxin Ren
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
| | - Xinhui Han
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
| | - Xiaojiao Wang
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
| | - Chengjie Ren
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China
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