土壤有机质对农田管理措施的动态响应

土壤有机质在农田肥力、环境保护、农业可持续发展等方面具有重要意义。它不仅决定农作物产量，而且在全球碳素循环中起着重要作用。由于大气CO2浓度升高与全球气候变暖等一系列环境问题的加剧，全球碳素循环受到越来越多的关注。农田具有大气CO2源和库的双重潜力。历史上由于人类对农田的过度开垦和耕种，造成土壤有机质含量大幅度下降，降低了农田的作物产量潜力；同时导致大量的碳以CO2形式由陆地生态系统排放到大气圈，加剧了全球温室效应。大量研究结果表明，诸如耕作、种植制度、施肥等农田管理措施能够显著地影响土壤有机质动态，而免耕、提高复种指数、合理的轮作换茬、有机肥料和化肥的施用以及弃耕农田还林还草等保护性管理措施则能够提高农田土壤有机质含量，使农田起到大气CO2汇的作用。综述了近年来农田管理对土壤有机质动态影响研究方面的进展。

The dynamics of soil organic matter in cropland responding to agricultural pract ices

The global agricultural land covers about 1.7×109 hm2, and its soil organic carbon (SOC) stock is about 170 Pg (1Pg=1015g), which exceeds 10 % of t he global terrestrial carbon pool. During the last two decades, CO 2 flux into at mosphere from land use changes was proximate half of the magnitude resulted from human activities, and 50 Pg SOC was lost in agricultural land due to the minera lization of soil organic matter. Soil organic matter (SOM) plays a crucial role in cropland fertility, environmen t ...