缓释尿素对两种土壤小麦氮素运转、产量和土壤无机氮的影响

Effects of Slow-released Urea on Nitrogen Translation and Yield of Wheat and Soil Inorganic Nitrogen in Two Soils

为探明缓释尿素与普通尿素掺混比例对安徽小麦花后氮素运转特征和土壤氮素盈余的影响,分别选择安徽省北方小麦产区小麦—玉米轮作和南方小麦产区小麦—水稻轮作方式,土壤类型分别为两合土和黄棕壤,设置不施氮肥处理(CK)、农民习惯处理(Ncon)、减少普通尿素用量的优化氮素处理(Nopt)、缓释尿素及其掺混普通尿素处理(SRU1、SRU2、SRU3)和普通尿素全部基施处理(SRU4),分析了不同施肥处理在两种土壤上小麦花后氮素转运、产量、氮肥利用率和土壤无机氮积累量。结果表明:与黄棕壤比较,相同施肥处理两合土上小麦产量、花后氮素积累量和氮素运转量显著增加,平均分别增加了71.8%,199.1%和25.8%,而氮素转移率和土壤氮素表观盈余量平均分别降低16.1%和49.7%。在两种土壤上,与Ncon比较,缓释尿素及其掺混普通尿素处理小麦产量差异不大,显著提高了氮肥利用率,黄棕壤和两合土上增幅分别达43.7%~91.9%和6.6%~26.9%,以缓释尿素掺混普通尿素比例2∶1处理(SRU2)最高;与Nopt相比,仅两合土上SRU2氮肥利用率显著提高。在小麦生育后期,农民习惯施肥处理0—30cm土壤NO_3^-—N和NH_4^+—N积累量明显高于缓释尿素处理,且土壤氮素盈余量高于其他处理。缓释尿素与尿素掺混实现了一次性简化施肥,可保障小麦产量、提高氮肥利用率、减少土壤氮素盈余量及降低环境污染风险。

In order to reveal the influence of the mix ratio between slow released urea（SRU）and ordinary urea on the nitrogen（N）translocation and soil mineral nitrogen accumulation of post-anthesis wheat,the effect of N managements of control（CK）,conventional（Ncon）,optimized（Nopt）,different mix ratios of SRU to urea（SRU1、SRU2、SRU3）,and only urea（SRU4）on post-anthesis N translocation,yield,nitrogen use efficiency（NUE）,soil NO_3^-—N and NH_4^＋—N accumulation of wheat was investigated via field experiments between the mixed soil and yellow-brown soil corresponding to the wheat-maize and wheat-rice rotation distributed over Anhui province.Results showed that the yield,the amount of post-anthesis N accumulation and translocation in mixed soil were higher than those in yellow-brown soil under the same treatment,which increased by 71.8%,199.1% and 25.8% on average,respectively.However,N translocation rate and apparent surplus amount of soil mineral N decreased by 16.1% and 49.7% on average in mixed soil than those in yellow-brown soil,respectively.Compared to the Ncon,yield showed no obvious differences,but NUE was significantly higher under the treatments of SRUs,which increased by 43.7%~91.9% and 6.6%~26.9% between mixed soil and yellow-brown soil.The highest NUE was under the treatment of SRU2（ratios of SRU to urea 2∶1）.Compared to the Nopt,NUE increased at significant level only under the treatment of SRU2 in mixed soil.There was more soil NO_3^-—N and NH_4^＋—N accumulation in 0—30 cm soil layer in Ncon than in SURs in post-anthesis of wheat,while the accumulation soil mineral N showedsimilar trend.The results showed it decreased accumulation soil mineral N under the treatments of SRUs in the late growth period of wheat with higher wheat yield and NUE.Therefore,one-time applying of the mix of SRU to urea could improve wheat yield,and reduce environmental pollution risk.