7Shoji S, Gandeza A T, Kimum K. Simulation of response to polyolefincoated urea: Ⅱ Nitrogen uptake by corn[J]. Soil Sci. Soc. Am. J.,1991, 55: 1468-1473.
8Salman O A. Polymer coating on urea pills to reduce dissolution rate[J]. J. Agrie. Food Anal., 1988, 13: 793-802.
9张治安,张美善,蔚荣海.植物生理学实验指导[M].北京:中国农业科技出版社,1998.43-45.Zhang Z A, Zhang M S, Wei R H. Experiment guidance of plant physiology[M]. Beijing: China Agricultural Scientech Press, 1998.43 -45.