LTREB: Long-Term Soil Organic Matter Dynamics in Subtropical Agroecosystems

9629770 Hendrix自1978年以来，在亚热带农业生态系统中，对耕作制度的影响和生物操作对土壤有机质（SOM）动态和养分循环过程的影响进行了长期研究。在格鲁吉亚大学马蹄弯曲试验区，经过15年的常规耕作和免耕管理，描述和监测了水稳性团聚体和团聚体相关土壤有机质的动态。免耕土壤中大团聚体的形成和稳定是保护和维持有机质的重要机制，否则可能会在传统耕作方式下丢失。这一机理可以解释免耕土壤有机质含量比常规耕作土壤高近18%的原因。有机质的这些差异转化为土壤生物多样性和生态系统功能的变化。LTREB提案的资金将维持这些长期实验，并允许进行一些短期的机械现场实验。土壤有机质的动态变化以及土壤群落对这些动态变化的反应是几十年来发生的。LTREB的资金将使这些调查人员有适当的时间来监测这些动态。

9629770 Hendrix Since 1978, long-term research has been conducted on the effects of tillage regimes and the impacts of biotic manipulations on soil organic matter (SOM) dynamics and nutrient cycling processes in a subtropical agroecosystem. After 15 years of conventional tillage and no tillage management, dynamics of water-stable aggregates and aggregate-associated soil organic matter have been described and monitored at the Horseshoe Bend experimental area at the University of Georgia. The formation and stabilization of macroaggregates in no tillage soils represents an important mechanism for the protection and maintenance of SOM that may otherwise be lost under conventional tillage practices. This mechanism may explain the nearly 18% higher soil organic matter content of no tillage soils as compared to conventional tillage soils. These differences in SOM are translated to changes in soil biodiversity and ecosystem functioning. Funding of this LTREB proposal will maintain these long-term experiments, and allow several short-term, mechanistic field experiments to be conducted. The dynamics of soil organic matter and the response by the soil community to these dynamics take place over decades. LTREB funding will allow these investigators the appropriate time frame to monitor these dynamics.