Effects Of Controlled Release Urae On Soil Ammonia Volatilization, Nitrogen Nutrient, Microbal Diversity And Yield Of Wheat

Modern agricultural production has caused severely environmental contamination by applying excessively readily available fertilizers in order to pursue high yielding. The effects of controlled release urea on soil ammonia volatilization, nitrogen nutrient, microbial diversity and wheat yield were researched to illustrate the agricultural and ecological effects of controlled released urea. This can provide theoretical supports for the application of controlled released urea and the development of sustainable agriculture.The field experiments and indoor chemical analyses were carried out to discus the effects of CRU on soil ammonia volatilization, nitrogen nutrient, microbial diversity and wheat yield. And the conclusions are as follows:1. Compared with urea, controlled released urea can postpone the appearance of the peak of SAV rate 3 to 5 days, decrease the peak value of SAV by 44.44%～69.51%, reduce the accumulative amount of SAV during wheat growth by 39.31%～52.11%. Compared with CRU coated by sulfur, controlled release urea coated by polymer can reduce the amount of SAV by 13.21%～21.08%.2. The amount of nitrate nitrogen, ammonium nitrogen, total nitrogen in top soil during the wheat growth can be maintained by CRU coated by sulfur or polymer, especially after the release rate postpone to the jointing stage of wheat, which can increase the content of available N (including NN and AN) persistently. In addition, CRU coated by sulfur or polymer can decrease the amount of available N and TN, maintain the content of N in upper profile soil and prevent the leaching loss of N nutrient. Moreover, The CRU coated by polymer can do these better than the CRU coated by sulfur.3. The CRU promotes the soil microbial diversity and activity, boost the nutrient transform and cycle rate in wheat rhizosphere. With the development of wheat, the CRU coated by polymer can maintain the microbial activity better than the CRU coated by sulfur. But in terms of soil microbial diversity index, it shows a reverse trend. 4. The controlled-release capability of CRU coated by sulfur or polymer increases the growing indexes significantly, such as the shoot height, length or width of leaf and chlorophyll. In addition, the CRU coated by sulfur or polymer can enhance the spike number, grain number and yields by 13.10% to 31.70%, and the increase production rate of the latter one is higher than the former one by 2.72% to 4.16%. What is more, the use efficiency of N applying CRU can reach from 48.93% to 59.26%, and the contribution rate of fertilizer of CRU coated by polymer is the highest.