添加尿素和秸秆对三熟制水旱轮作土壤各形态氮素的影响

发布时间：2018-09-10 13:45

【摘要】：添加不同外源氮对土壤中不同形态氮素的转化具有十分重要的影响。选取长期耕作土壤,设置对照、添加尿素N 150 kg/hm~2(U150)、添加秸秆(相当于添加N 38 kg/hm~2,Straw)、添加尿素N 150 kg/hm~2+秸秆(相当于添加N188 kg/hm~2,U150+Straw)和添加尿素N 188 kg/hm~2(U188)5个处理进行室内培养试验,研究了添加不同外源氮对土壤铵态氮、硝态氮、可溶性有机氮、微生物生物量氮含量的影响。结果表明,土壤铵态氮随着培养时间的延长表现为先增后减的趋势,添加尿素的两个处理其土壤铵态氮较Straw、U150+Straw处理能够更快地达到峰值;而土壤硝态氮则表现为逐步增加的趋势。添加尿素处理能够显著提高土壤矿质氮的含量,在添加等量氮素的条件下,U188处理矿质氮含量在培养期间始终高于U150+Straw处理;此外,U150+Straw处理矿质氮含量在培养前期均低于U150处理,至培养30天后其含量略高于U150处理。与对照相比,培养结束时添加不同外源氮素处理的土壤矿质氮含量能够提高169.61%~496.75%。对于微生物生物量氮和可溶性有机氮而言,添加不同外源氮素分别在培养10天和30天达到峰值,此后逐渐降低。不同处理而言,添加秸秆+尿素、添加秸秆处理的微生物生物量氮和可溶性有机氮含量在培养前期明显高于仅添加尿素的两个处理,说明添加有机物料氮源主要有益于提高土壤有机态的氮素含量。
[Abstract]:The addition of different exogenous nitrogen has a very important effect on the transformation of different forms of nitrogen in soil. Long-term tillage soil was selected and compared. Five treatments, urea N150 kg/hm~2 (U150), straw (equivalent to N38 kg/hm~2,Straw), urea N150 kg/hm~2 straw (equivalent to N188 kg/hm~2,U150 Straw) and urea N188 kg/hm~2 (U188), were added for indoor culture. The effects of different exogenous nitrogen on the contents of soil ammonium nitrogen, nitrate nitrogen, soluble organic nitrogen and microbial biomass nitrogen were studied. The results showed that the soil ammonium nitrogen increased first and then decreased with the increase of culture time, and the soil ammonium nitrogen reached the peak value faster than that of Straw,U150 Straw treatment. Soil nitrate nitrogen showed a gradual increase trend. The addition of urea could significantly increase the content of mineral nitrogen in soil, and the content of mineral nitrogen in U188 treatment was always higher than that in U150 Straw treatment during the culture period, in addition, the content of mineral nitrogen in U150 Straw treatment was lower than that in U150 treatment at the early stage of culture. After 30 days of culture, the content of U150 was slightly higher than that of U150. Compared with the control, the content of mineral nitrogen in the soil treated with different exogenous nitrogen at the end of culture could be increased by 169.61% and 496.75%. For microbial biomass nitrogen and soluble organic nitrogen, the addition of different exogenous nitrogen reached its peak value at 10 days and 30 days respectively, and then decreased gradually. When straw urea was added, the microbial biomass nitrogen and soluble organic nitrogen content of straw treatment were significantly higher than those of only urea treatment in the early stage of culture. The results showed that the addition of organic nitrogen sources was beneficial to the increase of soil organic nitrogen content.
【作者单位】：华中农业大学资源与环境学院/农业部长江中下游耕地保育重点实验室;
【基金】：国家自然科学基金项目(41301319) 湖北省自然科学基金项目(2013CFB203) 湖北省耕地保护与质量提升补贴项目(鄂土肥2015-8)资助
【分类号】：S153.6

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