关键词: 水性树脂包膜尿素, 氮素释放特征, 冬小麦, 氮素吸收, 土壤无机氮

Abstract:

【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.

Key words: water borne resin coating urea, nitrogen release characteristics, winter wheat, nitrogen uptake, soil inorganic nitrogen