等氮条件下长期施用有机物料氮替代部分无机氮对黑垆土氮素及相关酶活性的影响

Characters of soil nitrogen and enzymes involved in nitrogen metabolism under isonitrogenous organic material nitrogen partly replacing to chemical nitrogen

为研究长期施用不同有机物料氮替代部分无机氮对黑垆土氮素转化及酶活性的影响,在陇东旱塬上进行了连续12年的大田定位试验,研究了用生物有机肥、农家肥、小麦秸秆替代部分无机氮肥后0~10和10~20 cm土壤不同形态氮素和相关酶活性的变化特征。结果表明:与长期单施化肥相比,长期用3种有机物料氮替代部分无机氮均可提高土壤不同形态氮素含量和相关酶活性,其中施用生物有机肥的处理不同形态氮素含量和酶活性均最高;除硝酸还原酶外,铵态氮、硝态氮和微生物生物量氮含量以及脲酶、荧光素二乙酸酯水解酶活性均为上层土壤高于下层土壤。因此,生物有机肥是陇东旱塬黑垆土农业区替代部分无机氮的首选有机物料。

This research aims to compare the characters of soil nitrogen and enzymes involved in nitrogen metabolism when dif-ferent organic material nitrogen partly replacing chemical nitrogen. A successive 12-year field test was conducted in loessialsoil-covered areas in eastern Gansu province of the Loess Plateau, and the effects of 3 kinds of organic materials （including bio-organic fertilizer, farmyard manure and wheat straw） on soil nitrogen and enzymes involved in nitrogen metabolism of continu-ously-cropped winter wheat were investigated. The results showed that： compared with chemical fertilizer, all 3 organic materi-al nitrogen partly replacing chemical nitrogen exerted positive effects on soil nitrogen contents and enzymes activity involved innitrogen metabolism, especially under treatment of bio-organic fertilizer, all forms of soil nitrogen contents and enzymes activitywere the highest. Ammonium nitrogen, nitrate nitrogen, SMN contents, and urease, FDA hydrolase activities were higher inthe upper soil than the lower layer except nitrate reductase. Therefore, bio-organic fertilizer will be recommend the first-choiceamong bio-materials for partly replacing chemical fertilizers in rain-fed agricultural areas of eastern Gansu province.