Response Of Yield Of Maize Drip Irrigation Under Film Mulch To Its Influencing Factors And Research On Optimized Irrigation Scheduling

In this study,Yanggao County,Datong City,Shanxi Province was used as the study area,and the maize was used as the test crop,and the number of irrigation times and the planting density were designed as test variable.The effects of irrigation times,planting density and fertilization on the maize morphology,yield and the dynamics of soil water under drip irrigation under plastic film mulch were discussed.The correlation between water content of different depths of and water content of 0-80 cm depth was analyzed.The interface moisture flux was tested and analyzed.The effects of planting density and irrigation times on crop water consumption were compared.And the relationship between crop yield,irrigation and fertilization was established.Taking the maximum benefit as the goal,the paper puts forward the irrigation scheduling of drip irrigation in the whole province.The main conclusions are as follows:(1)The use of drip irrigation under film has obvious advantage than border irrigation under film.Its yield and water production efficiency significantly improved.Under the same irrigation amount(respectively 675m3/hm2,900m3/hm2,1125m3/hm2),compared with the border irrigation under film,the yield of drip irrigation under film mulch increased by 32.9%,18.0% and 42.5% respectively,and the water production efficiency increased by 34.9%,6.0% and 33.3%.(2)The growth of maize in appearance is a combination of crop physiological metabolism and external environmental constraints,affecting the quality and yield of crop yields.Using the data of this study(leaf length,leaf area,plant height),the growth status of maize in each growth stage was analyzed.The results showed that the change trend of leaf length and plant height in maize growth period was very fast(before July 29),but the growth of plant was increased from vegetative growth to reproductive growth in heading period.The speed began to slow down,no longer changing in grouting period(Around August 9).The effects of irrigation times on leaf width,plant height and leaf area were significant,and the planting density and fertilization had little effect on it.(3)Under the conditions of same irrigation times,single plant dry matter weight of planting density of 6000 plants/mu is the smallest,5000 plants/mu is the second,5500 plants/mu is the largest.Comprehensiving irrigation times and planting density two factors,the largest yield is 8426.4kg/hm2 under irrigation 3 times and planting density of 5500 plants / mu,for the appropriate planting mode of corn drip irrigation under film mulch in Yanggao County,Datong City,Shanxi Province,consistenting with the results of dry matter analysis.For the case of fertilization,given the planting density of 5500 plants / mu,irrigation 4 times,the amount of fertilizer as a variable,when the fertilizer rate of 450kg/hm2,the maximum yield is up to 9162kg/hm2.(4)Soil moisture monitoring can reflect the needs of crops for water,having a very important guiding significance to agricultural production.Selecting the appropriate soil moisture measurement hole location can be a better soil moisture real-time monitoring.When using a measuring point,the correlation between the moisture content of 40 cm depth under the film and the moisture content of 0-80 cm depth is the best.The correlation coefficient can reach 0.7971.When using two measuring points,the correlation between the moisture content of 40 cm depth under the film and between ridges and the moisture content of 0-80 cm depth is the best.The correlation coefficient can reach 0.7892.(5)In this study,PS123 model was used to simulate the dynamic process of crop assimilation.The simulated values of the leaf weight,stem weight and grain weight using the relationship between crop yield and irrigation fertilization were close to the measured values.The correlation coefficients of the average were 0.48,0.51,and 0.94.The correlation coefficients were respectively 0.31 ~ 0.71,0.33 ~ 0.67 and 0.87 ~ 0.996.The correlation between the simulated values and measured values of grain weight is the best,so the model for the simulation of crop yield has high accuracy.(6)The irrigation system of this study is to optimize the irrigation scheduling for an irrigation water supply and determine the optimal irrigation time.The goal of optimization is to maximize the benefit of the unit area.Due to the complexity of crop water demand and yield calculation,the optimization of irrigation schedule in this study belongs to the problem of nonlinear programming,which mainly limits the irrigation time.The results showed that the irrigation amount was different in different hydrological years.With the increasing of frequency,the number of irrigation increased,and the irrigation quota in 95% hydrological year was the highest.The range of irrigation quota was 900 ~ 1800m3/hm2.There were significant differences in irrigation schedule under the drip irrigation in the province.Taking the 95% hydrological year as an example,the number of irrigations in Yushe and Taiyuan irrigation areas was the highest,and the irrigation was carried out in 8 times,the number of irrigations in Youyu and Datong irrigation areas was the least,and the irrigation was only 4 times.In addition,considering the effect of the amount of fertilizer on the yield and benefit,by optimizing method,the yield and benefit are largest when the time of the topdressing water is set at the last three irrigation times.