| Rice is one of the main grain crops in China.The morpho-cultivation technology of rice is one of the effective ways to improve the quality and yield of rice in the cold area of north China.The traditional rice tray is mainly made of plastic materials,but there are some problems in the process of use,such as not easy to degrade,expensive supporting sowing and transplanting equipment,root injury and delayed seedling stage after transplanting,etc.Using crop straw to prepare nutritious rice tray for seedling cultivation is an effective way to solve the above problems.In this study,starting from the realization of the pot cultivation of rice and aiming at improving the quality of rice seedling cultivation and realizing the resource utilization of straw,the forming parameters of the rice nutritive seedling tray were optimized,and the field degradation of the rice nutritive seedling tray and the effect of seedling cultivation were tested.The specific research contents were as follows:(1)The main working parts of the rice nutritive rice plate molding device were designed,and the size of the rice plate was determined to be 581 mm long,273 mm wide and 16 mm thick.The main working parts of the rice vegetative plate forming device were designed,which provided the experimental basis for further research on the optimization of raw material ratio parameters of the vegetative rice plate with water straw.(2)Based on the results of single factor molding experiments,the value ranges of the content of molding additives,straw meal and cow manure were defined to carry out the optimization experiments of molding parameters.The pot hole molding rate,relaxation density,failure strength and seedling strength index were selected as the evaluation indexes of the molding performance of rice nutritive rice plate.The quadratic orthogonal rotation combination test with three factors and five levels was carried out,and the parameters of the optimal composition combination were optimized by response surface analysis method.Finally,the optimal raw material ratios of the vegetative rice tray were determined as follows: The content of molding additives is 39%,the content of straw powder is 24%,and the content of cow manure is45%.At this time,the theoretical pot hole molding rate is 98.9%,the relaxation density is21g/cm3,the failure strength is 27.8N,and the strong seedling index is 0.21,which can meet the requirements of the design of the seedling and agronomy.Experimental verification shows that the model has high reliability.(3)The degradation performance and degradation change characteristics of rice vegetative rice plate in the field were studied,and the influence rule of rice vegetative rice plate on soil environment was proved.The results showed that the degradation of vegetative rice tray began30 days after entering the field,and the degradation rate reached 84.79% after 120 days in the field.The degradation of rice vegetative plates in the field can improve soil nutrients.Soil organic matter,total nitrogen,alkali-hydrolyzed nitrogen,total phosphorus,available phosphorus,total potassium and available potassium under rice vegetative plates increased by 10.1%,22.2%,23.8%,18.02%,34.1%,6.6% and 32.3%,respectively.(4)On the basis of the optimal raw material ratio of rice vegetative tray obtained through experimental analysis,this study conducted a comparative test of seedling rearing effect.Compared with the traditional plastic tray,the effective panicle number,grain number per panicle,seed setting rate,1000-grain weight and yield of rice increased by 19.39%,7.04%,4.40%,8.98% and 10.80%,respectively,and the output value could be increased at the same time. |
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