Belowground litter decomposition represents an important source of the limiting nutrients nitrogen (N) and phosphorus (P) to forest soils. However, the rates and drivers of nutrient immobilization and release from root litter remain poorly understood. To address this gap, we conducted a seven-year field decomposition experiment using roots from three species, across five diameter classes (up to 20 mm) in a temperate forest. All roots released P to the surrounding soil within the first year of decomposition but immobilized N for much longer, particularly coarse roots. Long-term N release was mainly related to initial nutrient stoichiometry of the substrate, whereas P release was better predicted by substrate carbon (C) quality and decomposition rate. Initial root nutrients well predicted the difference between long-term N versus P release. Our results highlight the fact that N and P dynamics should be considered separately when modeling nutrient release during root decomposition.

Photosynthetically carbon (C) allocation largely determines yield and C sequestration of agroecosystem. However, how C allocation of crops responses to climate change at the long-time scale is poorly defined. Combining thirteen years of eddy covariance and inventory measurements, we comprehensively investigated C allocation mechanism in a winter-wheat and summer-maize double cropping field. Significantly increased gross primary production (GPP) was benefited from CO2 fertilization, and 35% of increased GPP transferred to strengthening C sequestration. However, elevated temperature and drying surface soil moisture stimulated the partitioning of GPP to autotrophic respiration, resulted in conservative net primary production and grain yield. Maize faced a greater risk of C loss and yield reduction than wheat to warming and drying. By synthesizing published long-term data of agroecosystems, we further highlight that the GPP partitioning cannot be simply predicted by allometric theory, particularly for grains, which should be considered in predicting C budget and crop yield.