玉米秸秆不同还田方式对土壤有机质及微生物数量的影响

2011～2015年采用玉米田间原位定位试验方法,探讨农户常规种植(根茬还田)、根茬+1/3秸秆还田、根茬+秸秆全量粉碎耕翻还田对土壤有机质及土壤微生物数量的影响。结果表明,根茬还田(对照)土壤有机质年下降0.14 g/kg,根茬+1/3秸秆还田和根茬+全部秸秆还田处理土壤有机质年分别提高0.03 g/kg和0.26 g/kg。同时,秸秆还田能显著增加细菌、真菌、放射菌、自生固氮菌、硝化细菌、纤维素分解菌的总体数量。根茬+1/3秸秆还田和根茬+秸秆全量粉碎耕翻还田后可使土壤有机质年提高,是吉林中部黑土农田提高土壤有机质可行的农艺措施。

Effects of Different Maize Straw-Returning Modes on Soil Organic Matter Contents and Microorganism Quantity

A field experiment was conducted to evaluate the effects of different maize straw-returning modes on soil organic matter content and microorganism quantity from the autumn of 2011 to the autumn of 2015. There were three treatments, maize straw-returning with stubbles of 60-70 cm height, namely, root stubble + 1/3 straw(Treatment A), maize straw-returning with all the crushed stalks, that is, root stubble + total straw(Treatment B), and a conventional farm planting pattern, that is, short stubble and root of maize remained in the field(CK). The results indicated that the soil organic matter was decreased by 0.14 g/kg per year in CK, while it was increased by 0.03 and 0.26 g/kg per year in Treatment A and Treatment B, respectively. Maize straw-returning can significantly increase the total numbers of bacteria, fungus, actinomycetes, azotobacter, nitrobacteria and cellulose decomposition bacterum. More than 1/3 of the maize straw should be given back farming. And maize straw-returning with the entire crushed stalks mode can make the soil organic matter increase. These are effective agronomic measures to improve the organic matter content in the soil steadily in the black farmland of central Jilin province.