关键词:
聚合材料, 包膜尿素, 成粒率, 抗压强度, 养分释放

Abstract: In order to investigate the urea nutrient releasing characteristics, this paper took organic material (starch A/ polyvinyl alcohol V) as substrate material, inorganic non-metallic mineral (diatomite G/ bentonite P/ zeolite powder F) as modified material to prepare composite material and coated urea, and measured granulation rate and compressive strength by water dissolution rate and soil incubation methods. Besides, the paper also probed into the nutrient release rule of coated fertilizer, and compared  the testing results of these 2 methods. The results showed that grain yield difference was significant in each particle size of coated urea, the granulation effect was the best in particle size 3~4 mm of the 3 kinds of coated urea, which was about 60%. The granulation effect and compressive strength all expressed AVGU>AVPU>AVFU, indicating the adhesive property was AVG>AVP>AVF. The nutrient release rate of coated fertilizer in soil and water and release duration were different. The initial dissolution rate of AVFU in water was as high as 30%, cumulative release rate of 7 d was as high as 75.02%, release duration was only about 11 d. Slow release performance of AVGU and AVPU nitrogen were significant. The initial dissolution rate was only about 12%~15%, the cumulative release rate of 7 d was 42.24%~58.36%, release  duration was about 36~44 d.  At the same time, the dissolution rate of soil nutrients was only 26%~57%, but the release duration was increased to 42~112 d. On the basis of polyvinyl alcohol starch polymer, the water resistance and slow release effect of the membrane material could be optimized by adding modifier. The water absorption character of film material was very good for ensuring the slow release of fertilizer nutrients, and preferably  providing nutrients for plant growth.

Key words: polymeric material, coated urea, granulation rate; , compressive strength, nutrient release