施用尿素和控释氮肥的双季稻田表层水氮素动态及其径流损失规律  

Dynamics of Floodwater Nitrogen and Its Runoff Loss, Urea and Controlled Release Nitrogen Fertilizer Application Regulation in Rice

作　　者：纪雄辉[1] 郑圣先[1] 鲁艳红[1] 廖育林[1] 

机构地区：[1]湖南省土壤肥料研究所

出　　处：《中国农业科学》2006年第12期2521-2530,共10页Scientia Agricultura Sinica

基　　金：国家自然科学基金项目(30270770);中加合作项目(HN-13)资助

摘　　要：目的通过比较研究洞庭湖区双季稻田施用尿素(CF)和控释氮肥(CRNF)的表层水pH、电导率(EC)、总氮(TN)、NH4+-N和NO3--N浓度变化动态及TN径流损失规律,寻找有效控制氮素流失的最佳施肥管理措施。方法在渗漏池中按河沙泥(ASP)和紫潮泥(PCP)土壤的剖面层次填装土壤,对天然降雨引起的稻田氮素径流损失进行模拟试验。结果稻田土壤施用尿素后,表层水TN、NH4+浓度分别在第1、3天达到高峰,然后随着时间的延长而迅速下降;早稻表层水pH在施用尿素后15d内(晚稻3d)逐渐升高,EC表现与NH4+的变化同步。与施用尿素相比,施用CRNF能显著降低稻田表层水TN、NH4+浓度峰值,pH、EC峰值也有明显下降。氮素径流损失监测结果显示,洞庭湖区双季稻田施用尿素TN径流损失量为7.47kg·ha-1,占施氮量的2.49%;施用CRNF、70%CRNF的TN损失量比施用CF的分别减少了24.5%和27.2%。早稻施肥后20d内发生的2次降雨径流事件,施用尿素、CRNF和70%CRNF处理的2次TN径流损失量分别占全生育期径流损失总量的72%、70%和58%。其中,早稻施肥后第10天发生的第1次径流的2个控释肥处理的TN损失比施用尿素分别降低了42.9%和44.2%。结论双季稻田施用尿素后15d内表层水氮素浓度高,是氮素流失的关键时期;控释氮肥能显著降低这个时期的表层水和所发生的径流液中的氮素浓度,从而显著削减水稻全生育期内的TN径流损失量。[Objective] The paper dealt with the effects of urea and controlled release nitrogen fertilizer （CRNF） on dynamics of pH, electronic conductivity （EC）, total nitrogen （TN）, NH4^＋-N and NO3-N in floodwater. It also looked at regulation of runoff TN loss from field-based two cropping rice in Dongting Lake. It looked for the best fertilization management for controlling N loss availably. [Method] N loss with natural rainfall runoff from paddy fields was monitored based on modeling alluvial sandy loamy paddy soil （ASP） and purple calcareous clayed paddy soil （PCP）. This was done using lysimeter and following the sequence of the soil profiles identified by soil profile investigation. [Result] After applying urea in paddy field-based two cropping rice, TN and NH4^＋-N concentrations in floodwater reached peak at the 1st day and the 3rd day, respectively, then went down rapidly over time; All the floodwater NO3-N concentrations were very low; The floodwater pH rose gradually from early rice within 15 days （late rice within 3days） after applying urea. EC was consistent with dynamics of NH4^＋-N. CRNF,.70%CRNF applied led to significantly lower floodwater TN and NH4^＋ concentrations. The result of monitoring for N loss with natural rainfall runoff indicated that runoff TN loss amount from paddy field-based two cropping rice with urea application in the Dongting Lake area was 7.47 kg·ha^-1. It accounted for 2.49% of urea-N applied. CRNF and 70% CRNF application decreased 24.5% and 27.2% compared with urea. The two runoff events, which occurred 20 days after application, were very important for TN loss from paddy field. TN loss with the two runoffs in urea, CRNF and 70%N CRNF treatments accounted for 72%, 70% and 58% of total TN loss with runoff in whole rice growth season, respectively. And TN loss with runoff in two CRNF treatments decreased 44.9% and 44.2% compared with urea. [Conclusion] The fifteen day period after applying urea was a critical time for N loss due to high floodwater N conc

关 键 词：控释氮肥 双季稻田 表层水 氮素 径流损失 

分 类 号：S511.42[农业科学—作物学]