竹炭包膜尿素氮释放特性的影响因素研究

Experimental Research on Factors Influencing Nitrogen Release Characteristics of Bamboo-charcoal Coated Urea

利用竹炭和高分子聚合物为包膜材料,制得不同包膜厚度的BCCU1和BCCU2两种竹炭包膜尿素;并以普通尿素作比较,对其养分缓释性能进行研究。结果表明,竹炭包膜尿素在各种土壤中的氮溶出率和氨挥发量均低于普通尿素。竹炭包膜尿素的氮溶出率随肥水比的增大和浸提温度的升高而显著增大,并且浸提温度越高,氮溶出率增加的幅度越大;浸提液中离子浓度越大,竹炭包膜尿素中氮溶出率越小;供试氮肥在沙质红壤土中的养分溶出率远高于其在石灰岩风化土中的溶出率。不同土壤类型对氮肥的氨挥发损失影响较大,供试氮肥在各种土壤中的氨累积挥发量大小顺序均为:沙质红壤土>石灰岩风化土>粘性红壤土;随土壤含水量的增加,普通尿素和竹炭包膜尿素的氨挥发量都递增,但后者氨挥发量受含水量增加的影响较前者小。

Two kinds of bamboo-charcoal coated urea （BCCU1 and BCCU2） were made of normal urea by coating with bamboo-charcoal and organic polymer in different thickness, and their nitrogen slow-release characteristics was compared with normal urea. The results showed that urea coated with bamboo-charcoal presented slow-release property of a low nitrogen leaching rate and a low ammonia volatilization rate to a certain extent. Under the same leaching conditions, the nutrient release rate of BCCU1 （coating rate 8.04%） was lower than that of BCCU2（coating rate 5.43%） i.e., the thicker the coating layer was, the slower its nutrient released. The nitrogen leaching rate of BCCU increased obviously as the increasing fertilizer/water ratio and the leaching temperature, but decreased as the increasing ion strength of the leaching solution. The nutrient leaching rate in sandy red soil was significantly higher than that in limestone soil. The ammonia volatilization of nitrogen fertilizers was considerably affected by soil types. The cumulative amount of ammonia volatilization abided by the following order： sandy red soil〉limestone soil〉clay red soil. The ammonia volatilization of both normal urea and BCCU increased as the increasing water content in soil.