缓释尿素在双季稻上的养分供应特征

Study on Nutrient Supply Characteristics of Slow-release Urea in Double-cropping Rice

采用双季早晚稻的田间试验,研究了养分释放期为60 d和90 d的两种不同缓释尿素对整个生育期内水稻养分吸收的影响。结果表明:60 d型缓释尿素一次性施用在早、晚稻上均达到了普通尿素分次施肥时的产量水平,而90 d型缓释尿素一次性施用在早稻上效果好晚稻上效果欠佳。60 d和90 d型缓释尿素一次性施用的优势在于能使水稻有较高的有效穗数及穗粒数,整个生育期地上植株氮(灌浆期不含籽粒)含量也显著高于普通尿素分次施肥、普通尿素一次施用及不施氮处理,而灌浆过程中籽粒、剑叶、倒二位及倒三位叶的氮含量及剑叶SPAD值(叶绿素相对含量)也均高于其他3个处理。两种缓释尿素均使水稻出现了不同程度的贪青状况,其中以90 d型缓释尿素贪青最为严重,60 d型缓释尿素的养分释放期对水稻较为适中而90天型缓释尿素较长。

The effects of controlled-release urea on nutrient absorption were studied in whole growth period of rice. The results showed that the 60-day slow-release urea treatment obtained the highest yields of the early and late rice. The 90-day slow-release urea treatment got the same yield level as the 60-day slow-release urea treatment in early flee, but significant lower yield of late rice than the 60-day slow-release urea treatment. Compared with urea split application, single basal application of the 60-day or 90-day slow-release urea got more effective panicles and grains per ear. Throughout the growth period of rice, N contents in shoots （not included grains in the filling stage） treated with the 90-day and 60-day slow-release urea were both significantly higher than those of the other three treatments （urea split application, ordinary urea single application and no N application）. During the filling stage, N contents in grains, the flag leaves, penultimate and third leaves, and SPAD values of flag leaves were all also significantly increased by application of the 90-day and 60-day slow-release urea compared with the other three treatments. However, the two kinds of slow release urea treatments resulted in unfavorable-delayed senescence of rice in different degrees, particularly in 90-day slow-release of slow-release urea. The nutrient release period of 60-day slow-release urea was more appropriate for rice growth than 90-day type one.