水性树脂包膜尿素氮素释放与冬小麦氮素吸收匹配特征

The Match of the Nitrogen Uptake in Winter Wheat and Nitrogen Release of Water Borne Resin Coated Urea

【目的】了解水性树脂包膜尿素氮素释放特征及其与冬小麦氮素吸收特性在时空上的匹配性,为其在冬小麦一次性施肥上的应用提供理论依据。【方法】通过室内和田间试验相结合,研究水性树脂包膜尿素外膜表面形貌特征、氮素在静水与麦田中的释放特征、氮素释放与冬小麦氮素吸收的相关关系,不同土层土壤无机氮含量的时间动态以及不同生育时期土壤有效氮累积量与冬小麦吸收量的匹配关系。【结果】水性树脂包膜尿素涂膜外观完整、致密,无明显孔隙。C型水性树脂包膜尿素,在水中的累积释放曲线呈"S"型,释放期约为45 d;在麦田中的累积释放曲线呈拉长"S"型,释放期约为180 d。水性树脂包膜尿素在土壤中的氮素累积释放量与冬小麦氮素累积吸收量呈极显著的线性正相关。水性树脂包膜尿素在田间的氮素释放峰有两个,分别在苗期和拔节期,分别占全年氮素释放量的30.83%和23.53%。从氮素吸收与氮素释放在生育期匹配性来看,孕穗期之前,两者呈"错峰"关系,氮素释放峰在前,氮素吸收峰在后。与普通尿素处理相比,水性树脂包膜尿素处理不同土层在关键生育期土壤硝、铵态氮含量和有效氮累积量显著增加,0—30 cm土层在冬小麦返青、孕穗、灌浆期,30—60 cm土层在冬小麦孕穗、扬花、灌浆期,60—90 cm土层在冬小麦返青、扬花、灌浆期。【结论】水性树脂包膜尿素,缓释性满足缓释肥国家标准;在静水和麦田中的氮素释放特征相似,但在麦田中的释放期更长;其在麦田中的氮素释放规律与冬小麦氮素吸收规律基本一致,只是在孕穗期之前释放峰对应的生育时期,较吸收峰提前了一个生育时期;水性树脂包膜尿素较普通尿素更能提高不同土层在冬小麦关键生育时期的氮素供应能力,实现氮素供应与冬小麦根系吸收在空间上的匹配。

【Objective】The objective of this study was to further understand the match of the nitrogen uptake in winter wheat and nitrogen release of water borne resin coated urea in time and space,and to provide a theoretical basis for its application in single fertilization in wheat.【Method】Through laboratory analysis and field experiment,the membrane surface morphology characteristics and nitrogen release characteristics in the water and in wheat fields of water borne coated urea were studied,as well as the relationship of nitrogen release in which and nitrogen uptake in winter wheat,time dynamics of inorganic nitrogen content in different soil layers,and the matching between soil available nitrogen accumulation and wheat absorption at different stages.【Result】Membrane surface of water borne resin coated urea was complete,compact,no obvious pore.The nitrogen cumulative release curve was a“S”type for the water borne resin coated urea(type C)in water,and the nitrogen sated release time was about 45 days;the cumulative release curve in the wheat field was elongated“S”type,and nitrogen sated release time was 180 days.There was a significant linear positive correlation between the nitrogen accumulative uptake account of winter wheat and the nitrogen accumulative release account of water borne resin coated urea in soil.The nitrogen release peak of the water borne resin coated urea in the field was two,in seedling stage and jointing stage,respectively,accounting for 30.83%and 23.53%of the total nitrogen release in the whole year,respectively.According to the matching between nitrogen absorption and nitrogen release in the growth period,the relationship between them was“staggered”ahead of booting stage,and the nitrogen release peak was ahead of the nitrogen absorption peak.Compared with common urea,water-borne resin coated urea application made the content of nitrate and ammonium nitrogen and the accumulation of available nitrogen increased significantly in different soil layers at the key growth stage.The soil layer of 0-30 cm was significantly increased in the wheat returning green,booting,filling period of 30 to 60 cm soil layer in winter wheat booting and blooming.The soil layer of 60-90 cm in grain filling stage was green,flowering and filling stage of winter wheat.【Conclusion】Water-based resin coated urea,its sustained-release performance met national standard of slow-release fertilizer;which nitrogen release characteristics was similar in water and wheat fields but longer in wheat fields;the nitrogen release in wheat field was basically the same as that of winter wheat,however,the time was ahead of a growing period for the appearance of nitrogen release peak than that of nitrogen absorption peak.Compared with common urea,applying waterborne resin coated urea could improve the nitrogen supply ability of different soil layers at the key growth stage of winter wheat,and realize the spatial matching between nitrogen supply and root absorption of winter wheat.