县域土壤有机质动态变化及其影响因素分析

本文以河北省曲周县为例, 采用 1980 年和 1999 年两次全县的土壤肥力监测以及农户调查数据和统计数据, 系统分析了过去 20 年中土壤有机质的动态及其与之相关的农作管理方式的变化。 结果显示, 在过去的近 20 年 间, 曲周县土壤表层的有机质含量呈现增长的趋势, 导致这种变化的农作管理方式有化肥施用量的大幅度提升、秸 秆还田量的增加、盐碱地的开垦利用、灌溉面积和复种指数的提高以及主要种植模式和种植作物的土壤有机质处 于正平衡状态。 然而当前的生产管理方式尽管有利于土壤有机质积累, 但是也带来了一系列的生态环境问题。 实 施保护性耕作、降低化肥用量、提高秸秆还田量和有机肥的用量成为今后农业生产管理方式调整的主要方向。

Dynamic change of soil organic matter and its affecting factors at county level

The study of the long-term dynamic change of soil organic matter (SOM) and its affecting factors of geoponic practices were important for a comprehensive management on soil fertility. In this paper, based on the soil fertilizer monitoring data in 1980 and 1999 at county level, household survey and statistics data, the dynamic change of soil organic matter (SOM) content and its affecting factors by relevant agricultural practices in the past twenty years were analyzed comprehensively. The results indicated SOM content in the surface layer took on a rising tendency in the last twenty years in Quzhou,Hebei province. The change of geoponic practices, including the dosage augment of fertilization, straw returning to field, reclamation of salinity soil, increment of irrigation area, enhancement of index of multiple plantation and positive SOM balance of the dominant cropping pattern and crop planting, contributed to the increment of SOM. Although the SOM content was improved, the current agricultural practices brought on a series of ecological problems as well. Implementation of conservation tillage, decrease of chemical fertilizer application, increment the rate of straw returning to field and organic fertilizer, should be the primary regulation direction of geoponic management in the future.