农业废弃物还田对土壤不同形态氮含量及氮肥利用率的影响

Effects of Agricultural Wastes Returnrd to the Field on Soil Nitrogen Content and Nitrogen Use Efficiency

采用田间试验的方法,对不同农业废弃物还田及不同还田量在0~100 cm土层全氮、铵态氮、硝态氮含量及产量和氮肥利用率的变化特征进行研究。结果表明:不同有机物还田对土壤全氮含量均表现为耕层土壤最高,随土层加深全氮含量逐渐减少,其中鸡粪还田对土壤全氮的含量影响最大,这表明农业废弃物与无机氮的配施在一定适宜的比例条件下,可以较为明显地提高土壤中全氮的含量。在施入等氮的条件下,土壤中铵态氮含量的变化较小,且各个时期土壤中铵态氮含量无明显变化;施肥对土壤中硝态氮含量影响较大,与化肥的施入量呈正相关,各个处理总体表现:单施化肥>25%有机肥+75%氮肥>50%有机肥+50%氮肥>75%有机肥+25%氮肥>不施肥处理,且对耕层土壤中硝态氮的含量影响较显著,对深层土壤硝态氮含量影响较小。各有机肥处理中以25%鸡粪+75%氮肥玉米产量最大,为9 331.1 kg/hm^2,氮肥利用率也达最高,为49.75%。综上,25%鸡粪+75%氮肥处理为最优。

The variation characteristics of total nitrogen, ammonium nitrogen, nitrate nitrogen, yield and nitrogen use efficiency in 0-100 cm soil layer were studied with different agricultural waste return and different returning amount by field experiment. The results showed that the total nitrogen was the highest in the topsoil with different organic matter return, and decreased gradually with soil depth, among which the effect of chicken manure on soil total nitrogen was the highest, indicating that the application of agricultural wastes with inorganic nitrogen in a proper proportion can significantly increase content of total nitrogen in soil. The content of ammonium nitrogen changed a little and without obvious changes in each period. Fertilization affected the content of nitrate nitrogen in soil greatly, and proportionally to the amount of fertilizer applied, and the overall performance of all the treatments is as follows: single fertilizer>25% organic fertilizer+75% nitrogen fertilizer>50% organic fertilizer+50% nitrogen fertilizer>75% organic manure + 25% nitrogen fertilizer> no fertilization. The application of fertilizer obviously affected the content of nitrate nitrogen in the topsoil, and had small effect on the content of nitrate nitrogen in deep soil. The yield of 25% chicken manure + 75% fertilizer treatment was the largest, reaching 9 331.1 kg/hm^2, and the nitrogen use efficiency was also the highest, reaching 49.75%. In conclusion, 25% chicken manure + 75% nitrogen fertilizer treatment is the optimal treatment.