Understory Plant Functional Types Alter Stoichiometry Correlations between Litter and Soil in Chinese Fir Plantations with N and P Addition

Altitudinal and aspect-driven variations in soil carbon storage potential in sub-tropical Himalayan forest ecosystem: assisting nature to combat climate change

Forest soils serve as the greatest sink of terrestrial carbon (C) and have a significant impact on worldwide or regional C cycling. By reducing emissions and enhancing the C storage in forests, the environmental monitoring function of a forest ecosystem may be ensured. The study focused on measuring the densities of major nutrients in soil to gain insight into the C and nitrogen dynamics of the Himalayan sub-tropical forest ecosystem of India besides supplementing the information about the C storage potential of these forest soils. The study examined the physico-chemical properties and nutrient densities across three altitudinal ranges viz., 600-800 m (A1), 800-1000 m (A2) and 1000-1200 m (A3) and two aspects, i.e. Northern (N) and Southern (S) in a randomized complete block design and data collection was done from 24 main sample plots (3 altitudinal ranges × 2 aspects × 4 replications). The soil pH, electrical conductivity, and bulk density observed a decreasing pattern with an increase in altitude, whereas a reverse trend was observed in soil organic C (SOC), total nitrogen and available phosphorus. The SOC and total nitrogen densities ranged from 20.08 to 48.35 Mg ha-1 and 2.56 to 4.01 Mg ha-1, respectively in an increasing trend from A1 to A3. The northern aspect exhibited significantly higher SOC and nitrogen densities than the southern aspects. The C storage potential of forest soils followed the order A1 < A2 < A3 with significantly higher potential (nearly 1.5 times) compared to those on the southern aspect. There was a consistently significant increase in the C:N ratio (CNR) with a maximum value (10.51) at A3 and minimum value (8.37) at A1, however the effect of aspect remained insignificant. This research underscores the importance of considering altitude and aspect when planning forest restoration efforts, as these factors have a substantial influence on soil properties, C storage potential and CNR. Understanding the significance of CNR is critical, as it serves as a key indicator of greenhouse gas (GHG) emissions from forest soils. Ultimately, these findings empower policymakers and conservationists to make informed decisions that can contribute to the sustainable management of Himalayan forests and the global fight against climate change.

Impact of Moso Bamboo (Phyllostachys edulis) Expansion into Japanese Cedar Plantations on Soil Fungal and Bacterial Community Compositions

Moso bamboo expansion is common across the world. The expansion of moso bamboo into adjacent forests altered plant and soil characteristics. While the community structure of soil fungi and bacteria plays an important role in maintaining the function of forest ecosystems, changes in microbial community compositions remain unclear, limiting our understanding of ecological process changes following moso bamboo expansion. To explore changes in the community structure of soil fungi and bacteria in Japanese cedar plantations experiencing expansion of moso bamboo, Illumina NovaSeq high-throughput sequencing technology was used to elucidate changes in soil microbial communities as well as alteration in litter and soil chemical characteristics. The results showed that moso bamboo expansion decreased content of soil organic carbon, total nitrogen, litter carbon, and the carbon to nitrogen ratio as well as the number of bacterial operational taxonomic units (OTUs) at the genus level, the α-diversity Simple index, and the abundance of Acidobacteria, Chloroflexi, and Gemmatimonadetes. Moso bamboo expansion also increased soil NH4+-N, pH, while it decreased fungi OTUs at the phyla, class, order, family, and genus level. The expansion of moso bamboo into Japanese cedar substantially altered soil fungal and bacterial community structure, which might have implications for changes in the ecosystem element-cycling process. In the forest ecosystem and expansion management of moso bamboo, the types and different expansion stages of moso bamboo should be paid attention to, in the assessment of ecological effects and soil microbial structure.

Biochar Addition Alters C: N: P Stoichiometry in Moss Crust-Soil Continuum in Gurbantünggüt Desert

The biogeochemical cycling of soil elements in ecosystems has changed under global changes, including nutrients essential for plant growth. The application of biochar can improve the utilization of soil nutrients by plants and change the stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in plants and soil. However, the response of ecological stoichiometry in a moss crust-soil continuum to local plant biochar addition in a desert ecosystem has not been comprehensively explored. Here, we conducted a four-level Seriphidium terrae-albae biochar addition experiment (CK, 0 t ha−1; T1, 3.185 t ha−1; T2, 6.37 t ha−1; T3, 12.74 t ha−1) to elucidate the influence of biochar input on C: N: P stoichiometry in moss crusts (surface) and their underlying soil (subsurface). The results showed that biochar addition significantly affected the C, N, and P both of moss crusts and their underlying soil (p < 0.001). Biochar addition increased soil C, N, and P concentrations, and the soil N content showed a monthly trend in T3. The C, N, and P concentrations of moss crusts increased with the addition levels of biochar, and the moss crust P concentrations showed an overall increasing trend by the month. Moreover, the soil and moss crust C: P and N: P ratios both increased. There was a significant correlation between moss crust C, N, and P and soil C and N. Additionally, nitrate nitrogen (NO3−N), N: P, C: P, EC, pH, soil moisture content (SMC), and N have significant effects on the C, N, and P of moss crusts in turn. This study revealed the contribution of biochar to the nutrient cycle of desert system plants and their underlying soil from the perspective of stoichiometric characteristics, which is a supplement to the theory of plant soil nutrition in desert ecosystems.

Soil C-N-P pools and stoichiometry as affected by intensive management of camellia oleifera plantations

Intensive management of C. oleifera has produced many pure C. oleifera plantations. The transmission of C. oleifera plantation will potentially affect soil C, N, and P pools as well as their stoichiometric characteristics both in top soil layer and vertical soil profile due to the intensive management. To understand changes in vertical pools and stoichiometric characteristics of soil C, N, and P as affected by intensive management of C. oleifera plantations, both mixed and pure C. oleifera plantations were studied. We conducted studies in five locations in Jiangxi, China with both pure and mixed C. oleifera plantations, to compare changes in vertical pools and stoichiometry of C, N, and P. Both C and N pools were significantly different between mixed and pure plantation types of C. oleifera. However, the ratio of C:N, C:P, and N:P was consistently higher in mixed plantations with C:P and N:P altered but C:N ratio did not change with soil depth. The intensive management significantly impact both C and N pools and the stoichiometry of C, N, and P. Intensive management of C. oleifera plantations decreased both C and N pools, especially at the depth of 30-50 cm soil layer. C. oleifera plantation alteration from mixed to pure should be considered in future forest management practice considering the substantial effects on soil element cycling and distribution along vertical soil profile.