沙壤土包膜尿素释放期与小麦适宜施用方式研究

【目的】在保水保肥性差、 氮素淋溶损失严重的姜堰高砂土地区,采用新型水基反应成膜技术的包膜尿素,研究可提高小麦产量以及氮肥利用率的肥料品种和施肥方法。【方法】本研究采用30、 60、 90 d三种控释期包膜尿素(PCU30、 PCU60、 PCU90)并各设置三种施肥方式处理: 播种行下方12 cm处一次基施、 播种行侧方3 cm深5 cm处一次基施、 播种行侧方10 cm深5 cm处一次基施(T1、 T2、 T3)。小麦成熟期测定各小麦秸秆和籽粒产量与干物质分配,测定氮素吸收量。【结果】三种包膜尿素中,施用PCU60增产效果最好,其侧施处理优于种下深施,其中T2处理的小麦产量最高,为8661 kg/hm2,比当地习惯施肥增产6.5%。PCU60 T2处理的氮肥利用率为53.7%,较习惯施肥提高17.3%,差异显著。PCU90各处理较习惯施肥均减产且收获期土壤硝态氮残留量高,不适合当地使用。【结论】在砂土基质下,PCU60在播种行侧方3 cm深5 cm处一次基施可替代尿素分次施用,降低劳动成本。

Release durations and suitable application patterns of coated urea on winter wheat in sandy loam soil

【Objectives】 Sandy loam soil is characterized by high permeability and low nutrients and water retention capacity. N loss through leaching is often occurred during winter wheat growing season in this type of soil. The effect of water-borne polymer-coated urea fertilizers was studied with different nutrient release durations and application patterns in order to improve winter wheat (Triticum aestivum L.) yield and N fertilizer use efficiency. 【Methods】 A field experiment of three water-borne polymer-coated urea fertilizers with different nutrient release duration (30, 60 and 90 d, hereafter namely PCU30, PCU60 and PCU90) and different application patterns once 12 cm underneath the seed (T1), once 3 cm away from and 5 cm underneath the seed (T2), once 10 cm away from and 5 cm underneath the seed (T3)] was conducted. The yield of straw and grain were measured, the N contents were determined at harvest.【Results】 The PCU60 presented the highest yield among those fertilizers and the effect was greater when applied away from the wheat seed than applied directly underneath it. The highest yield was 8661 kg/hm2 in T2 of PCU60 which increased by 6.5% compared with local farmer fertilization practice (FFP, urea application at 40%-30%-30%). The highest N use efficiency was 53.7% in T2 of PCU60 and was 17.3% higher than that in local fertilization practice. Regardless of fertilizer application patterns, yield and N use efficiency were lower and soil NO-3 concentration was higher in PCU90 than in local practice, thus PCU90 was not suitable for local agricultural management. 【Conclusions】 The PCU60 applied 3 cm away from and 5 cm underneath the wheat seed could significantly decrease labor input and increase wheat yield, so it is a suitable coated fertilizer in the sandy loam soil in Jiangyan Country.