60天释放期缓释尿素可实现早稻和晚稻的一次性基施

Slow-release urea of 60-day-release period is suitable for one basal application in early and late rice

【目的】缓释肥料是一次性施肥及减量化施肥的重要载体,探讨缓释尿素对水稻养分吸收动态及产量形成的影响,为新型肥料的研发以及水稻产量的进一步提高提供重要的理论指导。【方法】早稻及晚稻的大田试验共设5个处理:1)不施氮(CK);2)普通尿素分次施用(PU1,基肥50%、返青肥20%、拔节肥30%);3)普通尿素一次性基施(PU2);4)60天型养分释放期的缓释尿素一次性施用(PCU60);5)90天型养分释放期的缓释尿素一次性施用(PCU90)。除不施氮处理外,其他处理氮肥用量均为N 150 kg/hm^2,所有处理磷钾的用量分别为P_2O_5 55 kg/hm^2、K_2O 130 kg/hm^2,肥源分别为过磷酸钙及氯化钾。田间小区随机排列,各处理重复4次。在早稻拔节期、孕穗期、抽穗期及灌浆期采集植株样品进行养分分析,在灌浆期采集剑叶及籽粒样品进行养分分析,并测定灌浆期伤流液中氮的含量以及灌浆期剑叶SPAD值的变化;在早稻及晚稻采收后记录产量和产量构成要素。【结果】早稻产量以60天型缓释尿素处理及分次施肥处理最高,其次为普通尿素一次性施用处理及90天型缓释尿素处理,不施氮对照产量最低;而在晚稻上90天型缓释尿素处理、60天型缓释尿素处理与分次施肥处理之间水稻产量没有显著性差异。90天型缓释尿素养分释放期过长,导致了灌浆期氮素供应过剩,水稻贪青导致灌浆不足,降低了千粒重。90天及60天型缓释尿素的处理提高了早稻拔节期、孕穗期、抽穗期及灌浆期地上部及地下部氮、磷的含量,其中以90天型缓释尿素处理最高。在早稻灌浆期,90天及60天型缓释尿素的处理水稻剑叶及籽粒氮含量、茎导管伤流氮含量以及剑叶SPAD值均高于其他处理。一次性施用60天及90天缓释尿素还可以提高土壤碱解氮的含量。【结论】缓释尿素可以用于水稻一次性施肥,但在水稻上90天型缓释尿素的养分释放期过长,而60天型缓释尿素养分释放期适中。缓释尿素可以促进水稻对氮素的吸收并且可以用于减量化施肥,缓释尿素对磷的吸收有显著的协同作用,在施用缓释尿素时还可以适当减少磷的施用量。

【Objectives】Slow-release fertilizer is an important carrier for both single basal and reduction fertilization. This study explored the effect of controlled-release urea on nutrient absorption and yield formation of rice which could provide theoretical support for further increase rice yield and new fertilizer development.【Methods】Field experiments in early and late rice were set up with five different treatments described as below： No N fertilization, split application of urea（50% of base fertilizer, 20% of turning green fertilizer and 30%of jointing fertilizer）, single basal application of urea, single basal application of 60-day type urea and single basal application of 90-day type urea. Except no nitrogen treatment, all the other four treatments were fertilized with N 150 kg/hm^2. All the experimental fields were fertilized with P_2O_5 55 kg/hm2 and K_2O 130 kg/hm2, which were supplied by calcium superphosphate and potassium chloride. Shoot and root samples of early rice were collected at jointing, booting, heading and filling stage for analysis of N, P and K. Flag leaves and grains of early rice were collected at filling stage and analyzed for N, P and K. Bleaching sap N contents and SPAD values were also measured at the same stage. The yield and yield components were also recorded after the early and late rice harvest. 【Results】The highest yield of the early rice was 60-day type urea and split application of urea treatments, followed by the 90-day type urea and single basal application of urea treatments. The lowest yield occurred in no nitrogen application treatment. There was no significant difference in late rice yield between the90-day type urea, 60-day type urea and split application of urea treatments. Too long period of nutrient release group, such as 90-day type urea, led to excessive nitrogen supply at filling stage, which showed insufficient filling and 1000-grain weight reduction. Application of the 90-day type and 60-day type urea increased shoots and roots N and P contents at jointing, booting, heading and filling stage of the early rice, and the highest value occurred in the 90-day type urea treatment. The N content of flag leaf and grain, bleaching sap N contents and SPAD values were all increased by application of the 90-day type and 60-day type urea in the early rice. Single basal application of 60-day and 90-day type slow-release urea increased soil alkali-hydrolysable N contents. 【Conclusions】Suitable slow-release urea has been proved available for single basal fertilization in rice production. The nutrient release period of 90-day type urea is too long to meet the requirement of rice, but that of 60-day type is appropriate for the purpose, with one basal application of 60-day type urea, the N uptake is increased and P uptake is synergistically increased at the same time. There is also potential to decrease the N and P fertilizer input using60-day type urea.