Effects Of Variety And Sowing Date On Yield And Water Use Efficiency Of Maize

In the North China Plain,water resources are scarce and groundwater overexploitation is serious.It is an important way for maintain the sustainable development of regional agricultural production to adjusting planting structure and developing water-saving agriculture.Under the background of the structural adjustment for growing and water-saving mining system in the groundwater depression funnel area of the North China Plain,this paper comprehensively considers factors such as climatic conditions and precipitation distribution,and studies the effects of different varieties and sowing date treatments on crops growth development,yield component,water consumption and water use efficiency under the single cropping system of maize.The field experiment was carried out in the dryland water-saving agricultural experimental station of Hebei Academy of Agricultural and Forestry Sciences.The experiment was set up with two varieties,Zhengdan 958(Z)and Xianyu 335(X).Each variety was designed with four sowing dates,which were May 20(D1),June 5(D2),June 20(D3)and June 30(D4).The purpose of this study is to find out the best variety and sowing date configuration of maize under the single cropping system.The research results can provide scientific basis and technique supporting for the comprehensive management of regional groundwater overexploitation.The main results of this paper are as follows:(1)Under the same sowing date,the growth process of the two varieties of maize was basically the same.With the postpone of seedtimt,the growth days from sowing to tasseling stage decreased gradually,the growth days after tasseling stage increased,and the number of days in the whole growth period of maize decreased.Varieties had significant effects on plant height,stem thick and leaf area index of maize.Sowing date had significant effects on plant height,stem thick,leaf area index and dry matter weights over ground of maize.The interaction between the two only had significant effects on stem diameter and aboveground dry weight.Compared with Zhengdan 958,the maximum plant height and dry matter weights over ground of Xianyu 335 increased by 8.58%～10.14% and 4.50%～14.72%,respectively,but the maximum leaf area index decreased by 1.26%～15.63%.Under the same variety treatment,with the delay of sowing date,the plant height of maize increased continuously,and the maximum plant height of maize under D4 treatment increased by 9.94%～22.40%compared with D1-D3 treatment.The maximum stem diameter,maximum leaf area index and maximum aboveground dry matter mass of maize offer a trend of increasing first and then decreasing.The treatment with the largest three indexes was D3,which increased by5.16%～43.37%,4.49%～36.73% and 4.86%～34.37% respectively compared with other sowing dates.(2)The varieties had no significant influence on the photosynthesis rate,average transpiration rate and average stomatal conductivity of ear leaves after tasseling,and the sowing date had a significant effect on it.There was no significant difference in SPAD,photosynthesis rate,average transpiration rate and average stomatal conductance between the two varieties at the same sowing date.Under the condition of the same variety,with the delay of sowing date,the maximum SPAD,average net photosynthetic rate,average transpiration rate and average stomatal conductance of maize ear leaves showed a trend of increasing first and then decreasing,and the peak value appeared in D2 treatment.Compared with the other three treatments,the maximum SPAD of ear leaves increased by 2.03%～12.53%,the average net photosynthetic rate increased by 7.99%～39.41%,the average transpiration rate increased by 11.30%～55.61%,and the average stomatal conductance increased by 12.71%～53.28%.(3)The results of statistical analysis showed that varieties had significant effects on100-grain weight and grain yield.Sowing date had significant effects on 100-grain weight,grain number per spike and grain yield.The interaction between the two had a significant effect on the number of grains per spike.Compared with Zhengdan 958,the average grain filling rate of Xianyu 335 increased by 15.85%～20.02%,the 100-grain weight increased by4.75%～17.90%,and the grain yield increased by 5.79%～17.63%.With the delay of sowing date,the average grain filling rate and 100-grain weight of maize showed a decreasing trend,there was no significant difference in the number of spikes per unit area,and the number of grains per spike and grain yield showed a trend of increasing first and then decreasing.The treatment with the highest grain yield of maize was XD2,which had no significant difference with ZD2 treatment,but was significantly higher than other treatments.(4)Variety treatment had a significant effect on water use efficiency(WUE),and sowing date treatment had a significant effect on water consumption and WUE.Under the same sowing date,there was no significant difference in water consumption during the growth period of maize between the two varieties.The WUE of Xianyu 335 was 4.62%～15.44%higher than that of Zhengdan 958.Under the condition of the same variety,with the delay of sowing date,the water consumption of maize in the whole growth period showed an increasing trend,while WUE showed a decreasing trend.The highest WUE of Zhengdan 958 and Xianyu 335 maize was D2 and D1,respectively,which increased by 2.72%～40.97% and7.29%～37.07% compared with other sowing date treatments.Under different varieties and sowing date configurations,the highest WUE treatment was XD1,which was not significantly different from XD2 and ZD2 treatments but significantly higher than other treatments.Considering factors such as maize grain yield and water use efficiency,under the condition of only irrigation of seedling water under the one-year maize planting system in the groundwater overexploitation area of the North China Plain,the best sowing date of Zhengdan 958 and Xianyu 335 is June 5,Xianyu 335 has stronger comprehensive resistance and higher yield potential.