红壤稻田施用控释肥与氮素转化的关系

在湘南红壤稻田连续两年（2002—2003）采用田间试验与室内分析相结合的研究方法，对施用控释肥和尿素的稻田肥料氮转化与去向进行研究。结果表明，稻田氨挥发是氮素损失的主要原因。施用尿素，其氨挥发损失量达到施氮素总量的39.28%，施用控释肥（LCU70、LCU50），其氨挥发损失量分别占其施氮总量的19.99%和10.91%，比尿素的氨挥发氮素损失量降低19.29%~28.37%。田间表面水NH4-N浓度高峰期出现在施肥后的第1天，10d后下降到对照水平。田间氨挥发高峰期出现在施肥后的第3天，7d后下降到对照水平。施用控释肥（LCU70、LCU50），水稻对氮素的吸收利用率分别为80.5%、64.7%，比施尿素高50.5%、34.7%，差异极显著。

The Relationship of the Application of Controlled-release Fertilizer and the into Red Ice Paddy

Under the research of nitrogen transformation of the application of controlled release fertilizer and urea fertilizer into rice paddies, in the red soil hilly fields of southern Hunan for two consecutive years (2002—2003), with a systemic field observation combined with real time analysis, the results showed that the ammonia volatilization is the main reason of nitrogen loss. The application of Urea made the ammonia volatilization losses amounted to 39.28% of total nitrogen. While the application of controlled release fertilizer (LCU70. LCU50), made the ammonia volatilization losses of volume accounted for 19.99% and 10.91% of total nitrogen separately, which were 19.29%~28.37% lower than Urea Nitrogen ammonia volatilization loss.The concentration of NH4-N in field surface water peaks in the first days after fertilization, and drops to the comparison level in 10 days. The ammonia volatilization in the field peaks in the third days after fertilization, and drops to the comparison level in 7 days. Unde the application of controlled-release fertilizer (LCU70, LCU50), the nitrogen absorptivities of rice are 80.5% and 64.7%, respectively, which are 50.5 and 34.7% higher than that of urea, the difference is significant.