| Early rice Qiliangyou 2012,Zhongjiazao 17 and Xiangzaoxian 45 were used in this experiment.Late rice Taiyou 871 and Tianyouhuazhan were used as materials.Two sowing dates(normal sowing date and delayed sowing date)and three nitrogen ear fertilizer levels(30kg/hm~2,60kg/hm~2and 90kg/hm~2)were set.An experimental study on the effects of different sowing dates and nitrogen ear fertilizer levels on dry matter production,yield,yield composition and rice quality of double cropping indica rice was carried out at Jiangxi Red Soil Research Institute(Zhanggong Town,Jinxian County,Nanchang City,Jiangxi Province)from 2020 to 2021,The main results are as follows:1.Effects of different sowing dates and nitrogen Panicle Fertilizer Levels on the yield and yield composition of early indica rice:compared with the normal sowing date,the dry matter quality of panicle at maturity decreased significantly,and the number of grains per panicle and seed setting rate in the yield composition decreased significantly.Compared with the low nitrogen treatment of panicle fertilizer,the medium nitrogen treatment and high nitrogen treatment increased the yield of the two varieties by 5%-14%and 9%-22%respectively,which was mainly related to the increase of the number of effective panicles and the number of grains per panicle,and also significantly increased the dry matter accumulation at maturity.Compared with the normal sowing date treatment,the yield of the two varieties could be increased by increasing the application of nitrogen panicle fertilizer(high nitrogen)under the delayed sowing date,indicating that the appropriate application of panicle fertilizer could slow down the decline of the yield of early indica rice.2.Effects of different sowing dates and nitrogen Panicle Fertilizer Levels on rice quality of early indica rice:compared with normal sowing date,delayed sowing date treatment significantly reduced the head rice rate by 9.3%,resulting in the deterioration of processing quality;The chalky grain rate and chalkiness degree were reduced and the appearance quality was improved;In addition,the disintegration value of rice was reduced,the quality of rice,hardness,amylose and protein content were improved,and the cooking and eating quality became worse.Under the application of different nitrogen ear fertilizer,compared with the low nitrogen treatment,the medium and high nitrogen treatment significantly reduced the appearance quality of rice,reduced the disintegration value and gel consistency,and significantly increased the degradation value,hardness and protein,which was not conducive to the improvement of cooking and eating quality of rice.However,under the delayed sowing date,appropriate application of panicle fertilizer can significantly reduce the increase of rice hardness of early indica rice and improve the palatability of rice.3.Effects of different sowing dates and nitrogen Panicle Fertilizer Levels on the yield and yield composition of late indica rice:compared with the normal sowing date,the dry matter accumulation at maturity decreased significantly,and the number of effective panicles,grains per panicle,seed setting rate and 1000 grain weight in the yield composition decreased significantly.Compared with panicle fertilizer low nitrogen treatment,medium nitrogen treatment and high nitrogen treatment increased the yield of the two varieties by 3.2%-6.3%and 6.5%-10.5%respectively,which was mainly related to the increase of the number of effective panicles and the number of grains per panicle,and significantly increased the dry matter accumulation at maturity.Compared with the normal sowing date treatment,the yield decreased by33.3%under the high nitrogen treatment under the delayed sowing date.The reduction of nitrogen panicle fertilizer(low nitrogen)can significantly slow down the decline of yield.4.Effects of different sowing dates and nitrogen Panicle Fertilizer Levels on rice quality of late indica rice:compared with normal sowing date,delayed sowing date treatment significantly reduced the head rice rate of rice,resulting in the deterioration of processing quality;The chalky grain rate and chalkiness degree were reduced and the appearance quality was improved;In addition,it reduces the disintegration value of rice,improves the quality of rice,rice hardness,amylose and protein content,and makes the cooking and eating quality worse.Under the application of different nitrogen ear fertilizer,compared with the low nitrogen treatment,the medium and high nitrogen treatment significantly improved the processing quality,but reduced the appearance quality of rice,reduced the disintegration value and gel consistency,and significantly increased the degradation value,hardness and protein,which was not conducive to the improvement of cooking and eating quality of rice.However,compared with the normal sowing date,under the treatment of delayed sowing date,the average decline of disintegration value of the two varieties under high nitrogen,medium nitrogen and low nitrogen treatment were 13.1%,12.1%and 10.9%respectively,indicating that the appropriate reduction of panicle fertilizer can further slow down the influence of low temperature and weak light at the seed setting stage of late indica rice,weaken the decrease of disintegration value and improve the eating quality.In conclusion,rice with expected yield and quality can be obtained under the treatment of normal sowing date and 60kg/hm~2nitrogen panicle fertilizer in the double cropping indica rice area of South China.The yield and eating quality of early indica rice can be significantly improved by appropriately increasing the Panicle Fertilizer under the delayed sowing date.The panicle fertilizer should be appropriately reduced under the delayed sowing date of late indica rice to slow down the adverse effects of low temperature and weak light on the yield and quality of late indica rice at the seed setting stage,so as to improve the yield and quality of late indica rice. |
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