氮肥运筹对水稻生长、光合特性及产量的影响

Effects of Nitrogen Fertilizer Application on Rice Growth,Photosynthetic Characteristics and Yield

针对水稻‘越光’生产过程中氮肥的不合理施用、水稻生长和根系形态差、产量低等问题,通过田间试验研究氮肥运筹对‘越光’水稻生长、光合特性和产量的影响。试验采用随机区组设计,设置1个不施肥对照(T1)处理,设置4个施氮量相同、施用比例不同的处理,基肥、分蘖肥、穗肥和粒肥的施肥质量比分别为1∶1∶1∶1(T2,农民常规施肥)、5∶3∶2∶0(T3)、4∶3∶3∶0(T4)、3∶3∶4∶0(T5)。结果表明:T5处理水稻叶面积指数、叶片SPAD值和地上部干物质量高于其他处理,水稻根长、根表面积、根体积显著大于其他处理,能延缓水稻生育后期根系的早衰;T5处理水稻成熟期的净光合速率、气孔导度和蒸腾速率高于其他处理,比T2处理分别提高14.46%、14.75%和15.52%;T5处理水稻糙米产量最高,达到7.40 t/hm^(2),比T2处理提高10.64%;水稻糙米产量与光合特性、根系形态呈正相关。综上所述,适宜的氮肥施用比例能够改善水稻地上部干物质量和地下部根系形态,提高光合性能和产量。

In view of the problems of unreasonable application of nitrogen fertilizer,poor rice growth and root morphology,and low yield in the production process of rice‘Yueguang’,the effects of nitrogen fertilizer application on the growth,photosynthetic characteristics and yield of rice‘Yueguang’were investigated through field experiments.The experiments adopted random block design,with one treatment without fertilizer(T1),and four treatments with the same nitrogen application rate and different application ratios.The fertilization mass ratios of basal fertilizer,tillering fertilizer,panicle fertilizer and grain fertilizer was 1:1:1:1(T2,farmers’conventional fertilization),5:3:2:0(T3),4:3:3:0(T4),3:3:4:0(T5).The results showed that the LAI,SPAD value and biomass of above ground straw were higher in T5 treatment than in other treatments.And the root length,root surface area and root volume of rice were significantly higher than those of other treatments,which delayed the early senescence of rice roots.The results indicated that the net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)were higher in T5 treatment than other treatments in harvest stage,which were 14.46%,14.75%and 15.52%higher than that of T2 treatment,respectively.The yield of brown rice treated with T5 was the highest,reaching 7.40 t/hm^(2),which was 10.64%higher than that in T2 treatment.The yield of brown rice was positively correlated with photosynthetic characteristics and root morphology.To sum up,the appropriate proportion of nitrogen fertilizer application can improve the population quality of rice roots and root morphology,and also improve photosynthetic performance and yield.