土壤干湿交替对磷素释放的影响机制

Effects of alternate drying-rewetting process on migration and transformation of soil phosphorus

土壤的干湿交替是影响磷素的生物地球化学循环过程的重要因素。通过系统总结近些年有关土壤干湿交替引起的土壤微生物、团聚体变化影响磷素迁移转化的研究报道,归纳出了“胁迫假说”和“供应假说”,从中得出:干湿交替减少了细菌,但增加了革兰氏阳性细菌,使得超过一半的微生物死亡裂解释放磷;干土复湿过程比落干过程对团聚体的破坏更大,干燥程度为重新润湿时控制磷释放的主要决定因素等信息,为今后农田水分优化管理提供了理论依据。

Alternate drying-rewetting(DRW)events are one of the main driving factors for nutrient cycling in soil ecosystems,affecting the biogeochemical cycling of phosphorus.A systematic summary of studies and reports on the effects of changes in microorganisms and aggregates on phosphorus migration and transformation caused by changes in soil moisture under drying-rewetting events and the mainstream“stress hypothesis”and“supply hypothesis”.The results indicate:DRW reduced bacteria but increased Gram-positive bacteria,causing more than half of the microorganisms to die and release phosphorus;DRW process has more damage to aggregates than drying process,and the degree of dryness is the main determinant of controlling phosphorus release during rewetting.This review helps to develop future water optimum management of farmland.