Effects Of Different Organic Fertilizer Application Rates And Planting Densities On Yield Formation And Rice Quality Of Organically Cultivated Rice

The purpose of this study was to investigate the effects of different organic fertilizerapplication rates and planting densities on the yield formation and quality of organic cultivated rice.This experiment was carried out at Yazhong Village,Liangshang Town,Sansui County,Guizhou Province in 2019 and 2020,with Yixiangyou 2115 as the test variety and Laili organic fertilizer produced by Zunyi Junyu Biological Engineering Co.,Ltd.as the test fertilizer.A split-plot design was arranged with organic fertilizer application rates(F)as main plots and planting density(D)as subplots.The D was set three levels as D1(128,000 holes/hm~2),D2(167,000 holes/hm~2)and D3(238,000holes/hm~2),respectively,and the corresponding spacing of plants and rows were26cm×30cm,20cm×30cm,and 14cm×30cm,respectively.The F was set as F0(0kg/hm~2),F1(3000 kg/hm~2),F2(6000 kg/hm~2)and F3(9000 kg/hm~2),respectively.In order to provide some theoretical basis and practical guidance for the promotion of organically cultivated rice,the effects of different organic fertilizer application rates and planting densities on the yield and yield composition,crop population growth characteristics,nutrient absorption characteristics and quality of organic rice were studied.The main results are as follows:(1)With the increase of organic fertilizer application rates,the yield of organic cultivation rice increased significantly.The yield increase is not significant with the increase of planting density.In this experiment,the highest yield under D3F3 treatment was 5581.10 kg/hm~2 in 2019,and in 2020,the highest yield under D2F3 treatment was6742.85 kg/hm~2.(2)With the increase of organic fertilizer application rate,the number of effective panicle and grain number per panicle increased significantly,the 1000-grain weight increased first and then decreased.With the increase of planting density,the number of effective panicles increased significantly(144.99-176.59×10~4panicles/hm~2),while the number of grains per panicle decreased,and the seed setting increased first and then decreased,which results in a small increase in yield(4.78%-11.86%)(3)The plant height,the number of tillers,leaf area index,photosynthetic potential,leaf area ratio,dry matter accumulation,apparent dry matter output and apparent output rate,and crop growth rate of organically cultivated rice increased gradually with the increase of organic fertilizer application rate.Therefore,increasing the application rate of organic fertilizer can improve the quality of crop population.With the increase of planting density,the number of tillers,leaf area index,photosynthetic potential and leaf area ratio in the early-middle growth period increased significantly,while plant height and net assimilation rate of early-middle growth period decreased gradually,and the amount of dry matter output,rate of dry matter output,stem sheaths and leaves matter transformation increased firstly and then decreased.So,increasing planting density appropriately can improve population quality,while high planting density can inhibit the accumulation and transport of dry matter.(4)The transport amount and rate of N,P and K of organically cultivated rice increased gradually with the increase of organic fertilizer application rate,but the difference was not significant;the partial productivity of N,P and K decreased significantly with the increase of organic fertilizer application rate,and the harvest index of N,P,K also showed a trend of gradual decrease,among which N harvest index had a significant difference.With the increase of planting density,the partial productivity of N,P and K increased;the transport rate of N,P and K decreased,but the difference was not obvious,which indicated that increasing planting density could increase the contribution of N,P and K to yield,but high density inhibited the transport of nutrients.(5)Increasing the application rate of organic fertilizer can increase the brown rice rate,milled rice rate,head rice rate and crude protein content of organically cultivated rice,there were significant differences among treatments,and the highest values were reached in F3,which were 0.95%,1.45%,3.53%and 0.83%higher than that in no fertilization,respectively,reduce the chalky rice rate,chalkiness degree and amylose content.Compared with no fertilizer application,the application rate of organic fertilizer at 9000 kg/hm2 decreased by 7.14%,3.45%and 2.64%respectively.It indicates that increasing the application rate of organic fertilizer improved the quality of organically cultivated rice.With the increase of planting density,there was no significant change and difference except head rice rate and gel consistency increased.The results showed that increasing planting density had little effect on the quality of organic rice.(6)Comprehensive considering the yield and quality of organic cultivation rice,the recommended organic fertilizer application rates and the spacing between plants and rows are 9000kg/hm~2 and 20cm×30cm,respectively.