Plant-root-litter-soil C, N, P stoichiometry and plant phosphorus accumulation and utilization response to warming and phosphorus input in desert steppe

Nutrient cycling in desert steppe can be affected by continuous climate warming and exogenous nutrient inputs. This would alter plant nutrient uptake and utilization, affecting the plant production and service functions of desert ecosystems. However, we know remarkably little about the patterns of the plant-root-litter-soil system nutrient redistribution response to warming and phosphorus input in the P-limited desert steppe. The relationships between plant-root-litter-soil C, N, P contents, stoichiometry, and plant, root phosphorus accumulation and utilization are unclear. In this study, open-top chambers (OTCs) were used to simulate climate warming. We experimented with warming and phosphorus fertilizer application to explore the changes in C, N, P contents and stoichiometry along the plant-root-litter-soil continuum, and the relationships with plant, root phosphorus accumulation, and phosphorus utilization efficiency. The study demonstrated that warming increased root C, N contents, and root N:P, without a corresponding change in phosphorus content across the plant-root-litter-soil continuum. Phosphorus addition significantly elevated plant P, root P, litter P, and soil available phosphorus (AP) and decreased its C:P and N:P. Thereby boosting plant, root phosphorus accumulation and reducing plant, root phosphorus utilization efficiency, further affecting plant production. The key influence factors of plant, root phosphorus accumulation and utilization efficiency were root P, root C:N, and plant C:P. The results highlighted that the altered plant-root-litter-soil C:N:P stoichiometry induced by warming and exogenous phosphate fertilizer input would regulate plant, root phosphorus uptake and utilization patterns to adapt to the P-deficient soil environment in desert steppe.