Effects Of Controlled Release Characteristics Of Different Nutrients Coated Controlled Release Urea On Yield And Quality Of Rice

Rice is an important grain crop in China.Shandong is a traditional high quality rice producing area,and Shandong is in the transition zone between rice-wheat double cropping and spring rice.Due to different ecological zones and rice soil types,breeders have bred new rice varieties that can adapt to different regions,such as Shengxiang 66 adapted to lake irrigation areas in south shandong and southwest Shandong,and Jinjing 253 adapted to saline-alkali areas in Yellow River Delta.But it lacks the complementary fertilizer and the technology of light and simplified fertilization.At present,the formula of slow and controlled release fertilizer for rice in the market is single,which does not distinguish the difference between soil conditions and rice varieties in ecological areas,and cannot meet the nutritional requirements of new rice varieties in various rice regions.According to different soil conditions in different rice regions and different rice varieties,the effects of controlled release characteristics of different nutrients coated controlled release urea on rice yield and quality were studied to achieve high quality and high yield of main rice varieties.It is of great significance for the people to increase production and income.The experiment was carried out in Linyi and Dongying of Shandong Province from 2020 to 2021.Shengxiang 66 and Jinjing 253 were used as test rice,respectively.Controlled release urea（CRU）with a controlled release period of 30,50,70 and 90 days was applied at a total amount(300 kg·hm^-2)and a reduction of 20%(240 kg·hm^-2)in one-time;Common urea（U）was applied in several times and nitrogen blank was used as the control.The effects of different nutrient controlled release characteristics coated controlled release urea on rice yield formation and rice quality were systematically studied.The main results are as follows:（1）Effects of coated controlled release urea with different nutrient controlled-release characteristics on rice yield,nitrogen use efficiency and economic benefit.For Shengxiang 66 in Linyi reservoir irrigation area,in a two-year field experiment,CRU treatment significantly increased rice yield,nitrogen use efficiency and economic benefit compared with U treatment.Compared with U,CRU reduction 20%treatment had no significant difference.The best treatment was controlled release urea for 30 days,the annual yield was 11357.00 kg·hm^-2 and 10944.44 kg·hm^-2,respectively.Compared with common urea,one-time base application significantly increased rice yield by 14.39%and 20.50%,nitrogen use efficiency by 9.5%and 8.84%,and net income by 63.34%and 93.60%.For Jinjing 253 in Dongying coastal saline soil,in a two-year field experiment,CRU treatment increased rice yield,nitrogen use efficiency and economic benefit,but the difference was not significant.CRU reduction 20%treatment significantly reduced production compared with U treatment.The best treatment was the controlled release urea for 70 days,the annual yield was 9660.56 kg·hm^-2 and 9671.71 kg·hm^-2,respectively.Compared with common urea,one-time base application increased rice yield by 3.88%and 5.70%,nitrogen use efficiency by 5.45%and 1.60%,and net income by 18.10%and 24.13%.（2）Effects of coated controlled release urea with different nutrient controlled release characteristics on rice quality.For Shengxiang 66 in Linyi reservoir irrigation area,compared with U treatment,the CRU treatment did not improve the rice quality.However,after 20%reduced CRU,each treatment improved the processing quality,appearance quality and nutritional quality of rice.Among them,controlled release period 90 days controlled release urea reduced by 20%had the best rice quality.Compared with U treatment,the brown rice rate,precision rate and whole precision rate were increased by 5.19%,2.87%and 3.22%respectively;Chalkiness rate decreased by 0.32%,amylose content increased by 0.5%,and protein content decreased by2.14%;In terms of RVA characteristic spectrum value,compared with U treatment,the thermal viscosity,final viscosity,reduction value and gelatinization temperature were improved,and the peak viscosity and recovery value were reduced.For Jinjing 253 in Dongying coastal saline soil,CRU treatment with constant fertilization did not improve rice quality compared with U treatment.However,after 20%reduced CRU,compared with U treatment,each treatment improved rice processing quality and nutritional quality,but did not improve rice appearance quality.Among them,controlled release urea for 30 days reduced by 20%had the best quality.Compared with U treatment,the brown rice rate,precision rate and whole precision rate increased by 0.31%,2.06%and 2.02%,respectively;Amylose content increased by 0.10%,and protein content decreased by0.97%;In terms of RVA characteristic spectrum,compared with U treatment,the reduction value,recovery value and gelatinization temperature were improved,and the peak viscosity,disintegration value,thermal viscosity and final viscosity were reduced.