摘要：

为明确湖南双季稻区水稻生产适宜的施氮水平和灌溉方式,采用随机区组设计,以陵两优942和领优华占分别为早晚稻材料,设置N1~N3共3个施氮水平(早晚稻均分别为150,120,0 kg/hm²)和W1~W3共3个灌溉方式(早晚稻均分别为水层灌溉W1、湿润灌溉W2、干湿交替灌溉W3),研究不同水肥协同处理对双季杂交稻农艺性状及产量的影响。结果表明:增施氮肥能显著提高水稻SPAD值,但在早晚稻上整体呈N1和N2的SPAD值相近,而灌溉方式呈W3既能使早晚稻保持较高SPAD,也能避免后期贪青晚熟;水稻叶面积指数(LAI)在一定程度上同施氮量呈正比,在早稻(全生育期)和晚稻(生育前期)N1和N2之间的LAI值相近,但在晚稻(生育后期)N1高于N2,而灌溉方式对早晚稻LAI值影响较小,主要以W3略高;增施氮肥能显著促进水稻干物质量的积累,除早稻(乳熟期)单株干物质量呈N2高于N1和晚稻(齐穗期)呈N1高于N2外,早晚稻其余时期的单株干物质量呈N1和N2相近,整体上说明减氮并不会显著降低水稻单株干物质量,灌溉方式对早稻影响较小,对晚稻影响较大,整体早晚稻单株干物质量以W3增长效果较好,W2其次;增施氮肥能显著提高水稻理论、实际产量和有效穗数,但其在N1和N2表现效果相近,早晚稻N1、N2的实际产量相较对照组N3,增幅分别为53.21%~59.64%,21.65%~32.68%,说明早稻减氮增产效果明显,晚稻减氮效果增产不佳主要是因为高氮并非常规晚稻施氮水平,而灌溉方式对产量及产量构成因素均不存在显著性差异。水肥协同下N2W2、N2W3处理能使早晚稻获得较高的叶片SPAD和LAI,干物质积累和产量及产量构成因素下早稻以N2W3处理表现效果俱佳,晚稻以N1W3处理效果较好。综上,早稻以N2W3处理既能满足高产,也能起到节肥节水的作用;晚稻N2W3处理虽然在SPAD和LAI表现较好,但其干物质积累、产量表现不及N1W3处理,所以晚稻以N1W3处理增产效果明显。因此,从经济和生态效益来看,在干湿交替方式下,早稻以施氮量为120 kg/hm²、晚稻以150 kg/hm²、能充分发挥水肥互作效应,它们增产潜力俱佳,更利于水稻生长发育和提高产量。

关键词: 双季杂交稻, 水肥协同, 农艺性状, 产量

Abstract:

In order to determine the appropriate nitrogen application level and irrigation mode for rice production in Hunan double cropping rice area,a randomized block design was adopted.Lingliangyou 942 and Lingyouhuazhan were used as early and late rice materials respectively.Three nitrogen application levels of N1-N3(150,120,0 kg/ha for early and late rice respectively)and three irrigation modes of W1-W3(water layer irrigation,wet irrigation and dry wet alternating irrigation for early and late rice respectively)were set.The effects of different water and fertilizer synergistic treatments on agronomic characters and yield of Double-cropping Hybrid rice were studied.The results were as follows:The increase of nitrogen fertilizer could significantly improve the SPAD value of rice, but the SPAD values of N1 and N2 were similar in early and late rice as a whole, while the irrigation method was W3, which could not only maintain a high SPAD in early and late rice, but also avoided late green and late ripening. Rice leaf area index (LAI) was directly proportional to the amount of nitrogen applied to a certain extent. The LAI values between N1 and N2 were similar in the whole growth period of early rice and the early growth stage of late rice, but N1 was higher than N2 in the late growth stage of late rice, while irrigation methods had little effect on the LAI value of early and late rice, mainly W3 was slightly higher. The increase of nitrogen fertilizer could significantly promote the accumulation of dry matter mass of rice. Except that the dry matter mass per plant of early rice at milk stage was N2 higher than N1 and the dry matter mass per plant of late rice at full heading stage was N1 higher than N2, the dry matter mass per plant of early and late rice at other stages was N1 and N2 similar, which showed that nitrogen reduction would not significantly have reduced the dry matter mass per plant of paddy rice on the whole. The irrigation method had little impacted on early rice and great impacted on late rice. The overall dry matter mass per plant of early and late rice increases better with W3, W2 followed. Increasing nitrogen fertilizer application could significantly improve the theoretical, actual yield and effective panicle number of rice, but they were similar in N1 and N2. Compared with the control group N3, the actual yield of early and late rice N1 and N2 increased by 53.21%-59.64% and 21.65%-32.68% respectively, indicated that the effect of nitrogen reduction and yield increase in early rice was obvious, and the poor effect of nitrogen reduction and yield increase in late rice was mainly because high nitrogen was not the nitrogen application level of conventional late rice.There was no significant difference between irrigation methods and yield and yield components. Under the cooperation of water and fertilizer,N2W2,N2W3 treatment could make early and late rice obtain higher leaf SPAD and LAI. Under the factors of dry matter accumulation, yield and yield components, the effect of N2W3 treatment was better for early rice, and N1W3 treatment was better for late rice. In conclusion, N2W3 treatment of early rice could not only met high yield, but also saved fertilizer and water;although N2W3 treatment of late rice performed better in SPAD and LAI, its dry matter accumulation and yield performance were lower than N1W3 treatment, so N1W3 treatment of late rice had obvious yield increasing effect. Therefore, from the perspective of economic and ecological benefits, under the alternative mode of dry and wet, the nitrogen application rate of early rice was 120 kg/ha and that of late rice was 150 kg/ha, which could give full play to the interaction effect of water and fertilizer. They had good yield increasing potential, which was more conducive to the growth and development of rice and increased yield.

Key words: Double-cropping hybrid rice, Water-fertilizer synergy, Agronomic characters, Yield