| Southern Hunan is an important rice producing area in Hunan province,which plays an important role in ensuring national food security.In recent years,under the national policy guidance,the planting area of double-cropping hybrid rice showed the recovery trend.In order to improve the high yield,quality and efficiency cultivation techniques for double-cropping hybrid rice in southern Hunan,field experiments was conducted in Hengyang county,Hunan province in 2019-2020 to comparatively study effects of three kinds of nitrogen fertilizer management modes(base tillers fertilizer:panicle fertilizer:grain fertilizer,7:2:1,N1;6:3:1,N2;5:4:1,N3)on yield,rice quality and nitrogen use efficiency of double-cropping hybrid ricen under nitrogen application rate of 150 kg/hm~2.The main results are as follows:1.Nitrogen fertilizer management had significant effects on tiller dynamics of early and late rice varieties.Increasing the proportion of basal tiller fertilizer could promote tiller development of rice,and N1 treatment had a better effect,but heavy application of basal tiller fertilizer could lead to a large number of ineffective tillers and reduce the heading rate of rice.Finally,the spike rate and effective panicle number under N2 treatment were higher.2.Leaf area index(LAI)of rice was significantly affected by nitrogen fertilizer management.LAI of early and late rice was firstly increased and then decreased with the increment of panicle fertilizer proportion,and the maximum LAI was obtained under N2treatment.Nitrogen fertilizer management had a great effect on leaf SPAD values,and N1treatment had the highest SPAD values at tillering stage,and N2 treatment had the highest SPAD values after booting stage.3.Nitrogen fertilizer management had a significant effect on dry matter weight of rice.Increasing basal tiller fertilizer could improve dry matter accumulation in early stage,while increasing panicle fertilizer could significantly improve dry matter accumulation at middle and late stage.Compared with N1 treatment,the accumulation of dry matter in N2 and N3treatment was higher at maturity stage,and that in N2 treatment was higher than that in N3treatment.4.Nitrogen fertilizer management had a significant effect on the yield and yield components of double cropping rice.The yield of N2 treatment was the highest in early and late rice,and significantly higher than that of N1 treatment.The average biannual yield of N2 treatment was 14.08t/hm~2,which was 11.86%and 5.24%higher than that of N1 and N3respectively.From the point of view of yield components,the yield increase of N2 treatment was mainly due to the higher effective panicle number,grain number per panicle and seed setting rate.5.With the increment of panicle fertilizer proportion,the milling and appearance quality of rice were significantly improved,amylose content and gel consistency showed a decreasing trend,peak viscosity,hot slurry viscosity,disintegration value and final viscosity of rice were significantly decreased,reduction value was significantly increased,peak time and gelatinization temperature did not change significantly,and the cooking and eating quality of rice became worse.Among the three treatments,the milling and appearance quality of N2 treatment was the best,and the cooking and eating quality of N1 treatment was the best.6.Nitrogen fertilizer management significantly affected nitrogen accumulation and nitrogen use efficiency.Increasing panicle fertilizer ratio could increase nitrogen accumulation in rice.The nitrogen utilization efficiency indexes increased at first and then decreased with the increment of panicle fertilizer ratio,and the maximum treatment was gained in N2 treatment.Considering the yield,quality and nitrogen utilization efficiency of double cropping rice,the 6:3:1 treatment of basal tiller fertilizer,panicle fertilizer and grain fertilizer was the ideal nitrogen fertilizer management method for double cropping hybrid rice in southern Hunan. |
PDF Full Text Request