摘要
It is well known that aboveground productivity usually increases with precipitation.However,how belowground carbon(C)processes respond to changes in precipitation remains elusive,although belowground net primary productivity(BNPP)represents more than one-half of NPP and soil stores the largest terrestrial C in the biosphere.This paper reviews the patterns of belowground C processes(BNPP and soil C)in response to changes in precipitation from transect studies,manipulative experiments,modeling and data integration and synthesis.The results suggest the possible existence of nonlinear patterns of BNPP and soil C in response to changes in precipitation,which is largely different from linear response for aboveground productivity.C allocation,root turnover time and species composition may be three key processes underlying mechanisms of the nonlinear responses to changes in precipitation for belowground C processes.In addition,microbial community structure and long-term ecosystem processes(e.g.mineral assemblage,soil texture,aggregate stability)may also affect patterns of belowground C processes in response to changes in precipitation.At last,we discuss implications and future perspectives for potential nonlinear responses of belowground C processes to changes in precipitation.
众所周知,植物地上生产力通常随降水的增加而增加。地下净初级生产力(BNPP)占植物净初级生产力(NPP)总量的一半以上,并且土壤储存了生物圈中最大的陆地碳库,但地下碳(C)过程如何响应降水变化仍不明确。本文从样带研究、模拟实验、数据整合与集成等方面综述了地下碳过程(BNPP和土壤C)对降水变化的响应模式。结果表明,BNPP和土壤C含量对降水变化表现出非线性响应,这与地上生产力的线性响应存在较大差异。C分配、根系周转时间和植物物种组成可能是调控地下C过程对降水非线性响应的3个关键因素。此外,微生物群落结构和长期生态系统过程(如矿物组合、土壤质地、团聚体稳定性)也可能影响地下C过程对降水变化的响应模式。最后,本文讨论了地下C过程对降水变化非线性响应的潜在生态意义及未来工作展望。
基金
supported by the National Key Research and Development Program of China(2023YFF0806900)
the National Natural Science Foundation of China(31930072,32241032,42203076)
the Natural Science Foundation of Heilongjiang Province of China(ZD2021C002).
