二十八年来杭州市桐庐县耕地有机质变化及其改良

为了解杭州市桐庐县二十八年来有机质的变化特征，从而提出因地制宜的有机质改良措施，以期为提升桐庐县耕地地力和农业的持续发展作出贡献。现将桐庐县耕地有机质现状与第二次土壤普查数据进行比较。结果表明：二十八年间，杭州市桐庐县耕地有机质含量已经从30.9 g/kg下降到24.8 g/kg，下降了19.4%。其原因主要是绿肥种植面积减少，土地整理和建设用地面积的增加。但质地黏重的耕地有机质含量仍保持在原来的水平。为此，提出了秸秆还田，种植绿肥，增施畜禽粪肥和商品有机肥的增加有机质提升措施和推广适合桐庐县的油菜—单季水稻种植模式。

Changes of Organic Matter in Cropland in Tonglu County of Hangzhou over 28 Years and Its Improved Management

In order to understand organic manure variation characteristics over 28 years in Tonglu District, we put forward proper countermeasures of organic manure, and improve soil fertility and agriculture sustainable development in Tonglu County. The author used the status of farmland organic manure to compare in pair with the data measured in the second national soil surveys. The results showed that: levels of organic matter in cropland in Tonglu County of Hangzhou had declined by 19.4% (from 30.9 g/kg to 24.8 g/kg) over 28 years. The main reasons included the reduction of the acreage under green manure, the addition of land consolidation and construction land. But organic matter levels were now being maintained in the clayey soils. Therefore, the author put forward improvement measures, such as inputs of crop residue, fertilizing green manure, adding animal manure and organic fertilizer soil. The rotation system of rape-rice can be chosen to suit local cropland.