摘要：

为探明减氮增密对再生稻产量形成特性的影响,以杂交稻品种创两优669为材料,在3个施氮水平(N1:180 kg/hm²;N2:153 kg/hm²;N3:126 kg/hm²)与2个株行距(M1:20.0 cm×16.7 cm;M2:16.7 cm×16.7 cm)条件下开展了2 a大田试验。结果表明,减氮降低再生稻叶面积指数(LAI),但合理减氮范围内增密可提高主季和再生季的LAI,互作处理N1M2与N2M2的LAI 较高;减氮和增密均降低再生稻叶片SPAD值,但密度影响不显著;减氮导致干物质质量下降,而增密可显著提高干物质质量,互作处理N1M2与N2M2干物质质量较高。减氮降低再生稻产量,但在合理减氮范围内增密可提高产量,互作处理N1M2与N2M2产量较高。减氮显著降低主季有效穗数、穗粒数和再生季再生率、有效穗数,但增密对穗数有弥补作用,合理减氮增密(N2M2)能够协调产量构成因素的关系,从而获得较高产量。相关分析表明,合理减氮增密主要通过提高主季和再生季的LAI和干物质质量,提高主季的有效穗数和穗粒数以及再生季的有效穗数,进而提高再生稻产量。综合来看,减氮增密处理N2M2(施N 153 kg/hm²、株行距16.7 cm×16.7 cm)可以节氮15%,并可获得较高产量。

关键词: 再生稻, 氮肥, 密度, 产量

Abstract:

In order to investigate the effect of reducing nitrogen and increasing density on the yield formation characteristics of ratooning rice,hybrid rice variety Chuangliangyou 669 was used as the material to conduct two years of field experiments under conditions of three nitrogen application rates(N1:180 kg/ha;N2:153 kg/ha;N3:126 kg/ha)and two plant row spacing(M1:20.0 cm×16.7 cm;M2:16.7 cm×16.7 cm).The results showed that:reducing nitrogen reduced the leaf area index(LAI)of ratooning rice,but increasing density within a reasonable range of nitrogen reduction could increase the LAI of the main and ratooning seasons.The LAI of N1M2 and N2M2 was higher in the interaction treatments.Reducing nitrogen and increasing density both reduced the SPAD value of ratooning rice leaves,but the effect of density was not significant.Reducing nitrogen led to a decrease in dry matter weight,while increasing density could significantly increase dry matter weight.The interaction treatment of N1M2 and N2M2 had a higher dry matter weight.Reducing nitrogen reduced the yield of ratooning rice,but increasing density within a reasonable range of nitrogen reduction could increase yield.The interaction treatment of N1M2 and N2M2 had a higher yield.Reducing nitrogen significantly reduced the number of effective panicles in the main season,the total number of grains per panicle,and the regeneration rate and number of effective panicles in the ratooning season.However,increasing density had a compensatory effect on the number of panicles.Reasonable nitrogen reduction and density increase(N2M2)could coordinate the relationship among yield components and achieve higher yields.The correlation analysis showed that reasonable nitrogen reduction and density increase increased the effective number of panicles and total grains per panicle in the main season,as well as the effective number of panicles in ratooning season mainly by increasing LAI and dry matter weight of the main and ratooning season,and thereby improving the yield of ratooning rice.Overall,the nitrogen reduction and density increase treatment N2M2(nitrogen rate of 153 kg/ha,plant row spacing of 16.7 cm×16.7 cm)can save 15% nitrogen and achieve a higher yield.

Key words: Ratooning rice, Nitrogen, Density, Yield