秸秆还田和保护性耕作对砂姜黑土有机质和氮素养分的影响

通过田间试验,分别采集小麦成熟期、玉米成熟期和小麦播种期耕层土样,研究不同的秸秆还田方式(秸秆还田、焚烧还田和火粪还田)与保护性耕作(减耕和免耕)对砂姜黑土有机质和氮素养分的影响,以期得到培肥砂姜黑土的最佳方式。结果表明:作物秸秆还田可以增加砂姜黑土有机质和全氮的含量,但是对速效氮含量影响不大。在不同的秸秆还田和保护性耕作处理中,秸秆火粪还田和免耕条件下的秸秆还田对砂姜黑土有机质和全氮含量的增加效果最为明显。与对照相比,秸秆火粪还田后土壤有机质和全氮含量分别平均提高4.45 g/kg和0.131 g/kg;免耕条件下的秸秆还田其土壤有机质和全氮含量分别平均提高3.36 g/kg和0.095 g/kg;减耕条件下的秸秆还田和秸秆粉碎还田对增加砂姜黑土有机质和全氮含量的效果不显著;秸秆焚烧不能增加砂姜黑土有机质和全氮的含量。秸秆还田和保护性耕作不会大幅度提高砂姜黑土C/N进而影响土壤氮素养分的供应,同时秸秆还田能有效提高土壤微生物量碳氮,但微生物量的碳氮比却保持在适宜的范围内。

Effects of Straw Returning and Conservation Tillage Patterns on the Contents of Organic Matter and Nitrogen Nutrient in the Lime Concretion Black Soil

In this study, effects of straw returning and conservation tillage mode on the contents of organic matter and nitrogen nutrient in the lime concretion black soil were investigated by the field experiment so as to gain the best way of improving the soil fertility. The research results showed that: Straw returning increased the organic matter and total nitrogen content of the lime concretion black soil, but had little impact on the available nitrogen content of the soil. Among different straw returning and conservation tillage patterns, straw returning by fire dung and no-tillage plus straw returned patterns increased obviously organic matter and total nitrogen content of the soil, respectively. Compared with contrast, under the treatment of straw returning fire dung, the contents of soil organic matter and total nitrogen respectively were increased by 4.45 g/kg and 0.131 g/kg averagely; under the treatment of no-tillage plus straw returning, the contents of soil organic matter and total nitrogen respectively rose by 3.36 g/kg and 0.095 g/kg averagely; under the condition of reduced tillage plus straw returning and returning straw crushing, the contents of soil organic matter and total nitrogen content increased a little, but the effect is not so obvious; straw burning did not improve the contents of soil organic matter and nitrogen .Straw returning and conservation tillage did not significantly increase the ratio of C/N of the line concretion black soil which affected the nitrogen nutrient supply of the soil to the crop, Meanwhile straw returning and conservation tillage improved the soil microbial biomass respectively, but the ratio between microbial biomass carbon and nitrogen remained in the appropriate range.