4种缓控释氮肥的养分释放特征及肥效

Release Characteristics and Fertilizer Efficiency of Coated Controlled-release Nitrogen for Rice

水田氮肥利用率通常不到旱地的一半,施用缓控释氮肥是提高水田氮肥利用率的有效措施。以常规施肥为对照,通过动力学模拟,研究水稻田4种缓控释氮肥[植物油包膜尿素(PCU)、树脂包膜尿素(JZd)、脲甲醛(UF)、硫包衣尿素(SCU)]的养分释放特征,分析不同缓控释氮肥下水稻的氮素累积吸收量和氮肥利用率。结果表明:(1)4种缓控释氮素肥料28 d的养分累积释放率:JZd(94.5%)>PCU(63.5%)>SCU(52.6%)>UF(22.0%),在0~56 d,4种缓控释氮肥的养分累积释放率均迅速增加;在70 d后养分累积释放率趋于稳定;(2)4种不同缓控释氮肥氮素释放符合Elvoich方程,氮素的释放速率为:JZd>PCU>SCU>UF;(3)PCU的氮肥利用率最高,达到56.8%,比常规施肥处理高15.2%;其次是JZd,氮肥利用率最低的是UF,仅为33.7%;(4)PCU的产量最高,较常规施肥显著提高了17.4%。PCU的氮肥利用率及产量最高,对水田来说是一种较为合适的施肥方式。

The coated controlled-release urea for rice nitrogen fertilizer is an effective measure to improve the nitrogen use efficiency. Field experiments were carried out to investigate the effects of plant oil coated urea（PCU）, resin coat urea（JZd）, urea-formaldehyde（UF）, sulfur coated urea（SCU） on rice grain yield and nitrogen use efficiency. The results showed that：（1） the nutrient release rate of the four types of fertilizers at 28 d was in the order： JZd（94.5%） PCU（63.5%）SCU（52.6%）UF（22.0%）, between 0–56 d, the four types of fertilizers nitrogen accumulation of nutrient release rate increased rapidly, and tended to be stable after 70 d;（2） the four different slow controlled release nitrogen fertilizers conformed to the Elvoich equation, and b value size of the E1 ovich equation was in the order： JZdPCUSCUUF, those were consistent with the nutrient release rate of coated controlled-release urea;（3） the nitrogen absorption of the four types of fertilizers significantly increased at heading stage in rice, and all was higher than conventional fertilization; nitrogen utilization efficiency of PCU（56.8%） was the highest, and followed by JZd application; SCU and conventional fertilization had no significant differences for nitrogen utilization rates; nitrogen fertilizer utilization rate of UF was the lowest as about 33.7%.（4） rice grain yield for PCU application significantly increased by 17.4% compared with conventional fertilization. PCU is more reasonable under current situation because it can maintain high yield of cropping rice while has the highest utilization rate of nitrogen fertilizer.