控释肥对小麦/玉米农田土壤硝态氮累积和迁移的影响

Effects of the Controlled Release Fertilizer on Nitrate Accumulation and Migration in the Soil of Wheat-Maize Rotation System

【目的】利用田间试验研究树脂包膜控释尿素对冬小麦夏玉米产量、肥料表观利用率、氮肥表观损失量、土壤硝态氮的累积和迁移规律的影响,为一次性施肥技术的发展提供重要的理论指导。【方法】对冬小麦-夏玉米轮作的大田试验设置3个处理:(1)不施氮(CK);(2)普通尿素优化施肥处理(OPT,基施50%,小麦返青、玉米拔节50%);(3)树脂包膜尿素一次性施肥处理(CRF,80%OPT施氮量)。小麦OPT和CRF处理氮用量分别为180和144 kg·hm^(-2),玉米OPT和CRF处理氮分别为210和168 kg·hm^(-2),小麦磷钾的施用量分别为P2O5 90 kg·hm^(-2)、K2O 60 kg·hm^(-2),玉米磷钾的施用量分别为P2O5 60 kg·hm^(-2)、K2O 60 kg·hm^(-2),肥源分别为过磷酸钙和氯化钾。在小麦返青期、拔节期、孕穗期和收获期以及玉米苗期、拔节期、灌浆期和成熟期按照20 cm土层采集0—100 cm土壤剖面土样进行分析,在收获时收集植株叶片及籽粒样品进行养分分析并测定其产量。【结果】与优化施肥相比,控释肥在减少20%施氮量的情况下,小麦产量达到7.87 t·hm^(-2),地上部总氮吸收量为209 kg·hm^(-2),玉米产量和吸氮量分别为7.57 t·hm^(-2)和142 kg·hm^(-2),不仅保证了小麦、玉米的产量和地上部总氮吸收量,小麦玉米持续施用控释肥还减少了土壤中氮的表观损失量。土层中硝态氮素累积主要发生在40—60 cm土层,控释肥能够有效减少硝态氮在0—100 cm土层中的累积量,同时减缓硝态氮向深层土壤迁移的速率。【结论】在冬小麦-夏玉米体系中,控释肥能够实现减量施氮不减产,同时减少氮肥损失,降低土壤中硝态氮的累积和迁移,降低环境风险。

【Objective】This study explored the effects of urea coated by resin on the crop yield,nitrogen(N)recovery efficiency,N apparent loss,nitrate accumulation and migration of winter wheat and summer maize,which could provide theoretical support for further development of one-off fertilization technique.【Method】Field experiments in winter wheat-summer maize were set up with four different treatments,described as below:(1)No N fertilizer(CK),(2)Optimal fertilization by split application of urea(OPT,50%of base fertilizer,50%of turning green fertilizer of wheat and jointing fertilizer of maize,(3)single basal application of resin coated urea(CRF,80%N rate of OPT).The OPT and CRF in wheat were fertilized with N 180 kg·hm^-2 and 144 kg·hm^-2,respectively,which in maize were 210 kg·hm^-2 and 168 kg·hm^-2,respectively.All the experimental fields were fertilized with P2O5 90 kg·hm^-2,K2O 60 kg·hm^-2 in wheat,and P2O5 60 kg·hm^-2,K2O 60 kg·hm^-2 in maize,which were supplied by calcium superphosphate and potassium chloride.The 0-100 cm soil samples were collected at 20 cm increments during the period of returning green stage,jointing stage,booting stage and after harvest for the winter wheat;and seeding stage,jointing stage,filling stage and harvest stage for the summer maize.Shoot and grain samples of crops were collected at harvest stage to analyze nutrients.【Result】Compared with OPT,the yield of CRF reached 7.87 t·hm^-2,the total N absorption of aboveground was 209 kg·hm^-2,and the maize yield and N uptake were 7.57 t·hm^-2 and 142 kg·hm^-2,respectively.It not only ensured the yield and total N uptake in wheat and maize,but also decreased the apparent N loss in soil in the wheat and maize rotation system.The 40-60 cm soil layer was the main location that nitrate accumulation.The application of CRF could effectively reduce the accumulation of nitrate in 0-100 cm soil layer,and slowing down the rate of nitrate migrate to the deep soil.【Conclusion】In the winter wheat-summer maize system,CRF with less N input could reduce the nitrate accumulation and migration in the soil without reducing yield and N uptake.Application of CRF could reduce the environmental risk from the apparent N loss in the soil.