Construction Of Stable And Efficient Planting System And Evaluation Of Nitrogen Flow Efficiency In Main Maize Producing Areas Of Jilin Province

Aiming at the demand of the stable and efficient corn production system to the development of main grain producing areas in China,this study takes corn production in main corn producing areas in Jilin province as the research object.Field experiments were carried out to identify the appropriate variety density,optimize the nitrogen fertilizer operation,improve the tillage mode,and return the organic material to the field,so as to establish a stable and efficient maize planting system.And the application verification in the new agricultural business entity;At the same time,based on the integrated management theory of nutrient resources,the nitrogen flow characteristics and nitrogen utilization efficiency of farming and pastoral systems in Jilin province were analyzed by using NUFER model.Furthermore,constructive Suggestions are put forward for the corn industry system in this region,and the stable and efficient planting system and production change trend are made clear.The main research results are as follows:1.The optimum density of cultivars was studied and the optimum density of cultivars was determined.The experiments were carried out simultaneously in Gongzhuling and Halahai with the double factors of variety and density,and the results showed that the nitrogen uptake,nitrogen transfer rate and contribution rate of stem and leaf were significantly different from each other by variety,region,planting density and year.The leaf area decreased with the increase of planting density,but the compensation effect of increasing planting density could further improve the leaf area of the population.The increase of planting density improved the dry matter quality and yield of crops,promoted the dry matter accumulation of stems and leaves and the transfer of nitrogen to grains,and ensured the high yield of crops.The optimum planting densities of ZD958,XY335 and LM33 were 78.3,77.0and 84.0×10³ plants·ha^-1,respectively.2.Based on the law of nitrogen fertilizer operation,a reasonable measure to optimize nitrogen fertilizer operation was put forward.Selecting varieties XY335,under the condition of the density of 75×10³ plantsha^-1,optimized n application rate of 225 kg·ha^-1,average yields at about 123 t·ha^-1,kernels per plant nitrogen uptake in 1.68?2.75g,with a mean of 229g,instructions in planting density increase,through reasonable nitrogen management,plant grain nitrogen uptake will decline,but at the same time,nitrogen uptake is greatly increased,which further increases the quality of population dry matter and nitrogen accumulation amount;It can significantly improve the ability of nitrogen utilization and the ability to move to grain nutrient.At the same time,higher LAI could be maintained at the late stage of silking,photosynthetic potential could be expanded,photosynthetic product accumulation in plants could be promoted,and plant greenness could be prolonged.3.Through the research of improving tillage method,the advanced tillage mode is constructed.Deep loosening+N deep with and cooperate with increasing organic fertilizer application treatment compared to 20?40 cm soil layer under three closer to the ideal value,is more important for the improvement of soil structure,and at the same time,increased by 20?40cm soil layer,the content of inorganic nitrogen in the soil of roots for absorption and utilization of nutrients in the soil,water plays an important role,and in the stage,more obvious.Compared with conventional cultivation,deep pine could increase dry matter weight and grain yield,especially the yield of deep pine and comprehensive fertilization,which increased by 8.9?16.5%and 9.2?18.1%,respectively.4.The fertilization mechanism of organic material returning to field was studied.After returning to the field,different types of organic materials significantly increased the content of organic matter in the tilled soil(0?20cm).NPK+composting treatment was more conducive to the accumulation of total nitrogen,total phosphorus,available nitrogen and available phosphorus in the tilled soil,so higher water use efficiency could be obtained.The yield of corn was increased by increasing the yield of corn,the number of grains per ear and the weight of100 grains.5.The planting mode system of corn with stable yield and high efficiency in Jilin province was put forward and applied to the new agricultural business.There are significant differences in soil fertility,relative input and cost in different regions of Jilin province.The ratio of fertilizer application to yield and benefit was the highest in the middle region.The model of planting corn with stable yield and high efficiency was established.Compared with ordinary farmers,the new operators increased the yield of corn by 7.8%on average.Fertilizer production efficiency and water production efficiency have also been significantly improved compared with farmers'habits,and the average increase is 7.2%and 7.2%respectively.Compared with farmers,the greenhouse gas emissions in the demonstration areas were reduced by 3.1%and the greenhouse gas intensity by 11.4%.This shows that the establishment of maize planting mode with stable yield and high efficiency in the demonstration area not only increases the economic benefits but also has better environmental benefits.6.The nitrogen flow efficiency in jilin province was evaluated by NUFER model.NUFER model for Jilin province farming system flow and nitrogen efficiency of nitrogen analysis,show that Jilin province farming system in the process of the nitrogen flow,rise of nitrogen input,but farmland in improving production of nitrogen utilization and Jilin province regional farmland nitrogen utilization efficiency(NUEc)was 25.11%?43.6%,farming system integrated nitrogen utilization(NUEc+a)was 8.87?16.97%,utilization rate of nitrogen cycle is on the decline at the same time,from 43.77%in 1997 to 40.55%by 2017.