2026-10-06T22:27:19Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33771394 2026-09-15T05:26:26Z category_26986 category_26983 item_type_3 month_year_09_2026

<b>Rate and placement depth determine the effects of yak dung-derived biochar on microbial resource acquisition and soil organic carbon in degraded alpine grassland</b>m Tahmina Kausar (21693482) Soil chemistry and soil carbon sequestration (excl. carbon sequestration science) Soil biology biochar ash <p dir="ltr">Biochar is a promising soil amendment for regulating nutrient cycling, microbial resource limitation, and SOC storage. However, how biochar application rate and placement depth regulate these relationships in degraded alpine grasslands remains unclear. This study examined the effects of yak dung derived biochar on ecoenzymatic stoichiometry, microbial nutrient limitation, estimated carbon use efficiency (CUE_ST), and SOC stock. Biochar was applied at 200, 400, and 600 g m⁻² to topsoil at 0–15 cm or subsoil at 15–30 cm. Soil nutrients, microbial biomass, and enzyme activities were assessed alongside vector and threshold indices. In the topsoil, the medium application rate (TBCM) increased ammonium N and microbial biomass carbon (MBC) by 66.9% and 162.6%, respectively, compared with the control. Increased ecoenzymatic C:N ratios accompanied a decline in vector length from 0.76–0.56, suggesting weaker relative C limitation. Vector angle increased from approximately 50°–56°, crossing the adopted 55° threshold, while the N limitation index decline. Together, these indices suggested alleviation of relative N limitation and a shift toward P limitation. These responses coincided with an increase in CUE_ST from approximately 0.28–0.35. In the subsoil, the high subsoil application rate (SBCH) increased total dissolved N and DOC by 20.6% and 71.2%, respectively, while vector angle declined from approximately 64°–50°, suggesting a shift toward relative N limitation. Structural equation modelling indicated associations among soil nutrient conditions, microbial resource limitation, CUE_ST, and SOC stock. Plant richness increased under TBCM but was not a significant SOC stock predictor. Overall, these findings link improved N availability with altered microbial resource acquisition and carbon allocation, while indicating that nutrient limitation responses depend on application rate and soil depth.</p> 2026-09-15T05:26:26Z Dataset Dataset 10.6084/m9.figshare.33771394.v1 https://figshare.com/articles/dataset/_b_Rate_and_placement_depth_determine_the_effects_of_yak_dung-derived_biochar_on_microbial_resource_acquisition_and_soil_organic_carbon_in_degraded_alpine_grassland_b_m/33771394 CC BY 4.0