Effects Of Nitrogen Application Rate On Growth And Yield Of Different Spring Maize In Weibei Rainfed Highland

Weibei dry land is located in the south of the Loess Plateau semi-humid and arid areas,annual precipitation of 530-630 mm,mainly concentrated in July-September,Weibei dryland is an important grain production base in Shaanxi Province,spring ma is the region In the winter wheat,the planting area of spring maize in Weibei dryland is gradually expanded,and the yield of spring maize is higher than that of winter wheat.However,due to the fertility of fertility and drought and other factors of stress,Weibei dryland spring corn production has been hovering.In order to screen the suitable nitrogen fertilizer for spring maize cultivation in Weibei dryland,the varieties of spring maize(Zhengdan 958 and Shanbai 8806)were mixed with nitrogen fertilizer gradient(0,75,150,270,360 kg/hm2),the main research progress is as follows:(1)Effects of different nitrogen treatments on soil water contentUnder the experimental conditions,the soil water content decreased with the increase of nitrogen application rate,and the soil water content was the lowest when N270 was treated.The effect of nitrogen application rate on the soil water storage capacity of each soil layer was significant,the soil water content of 0-20 cm soil layer is the most obvious in the growth period,and the soil layer below 60-40 cm is not obvious.The soil water storage is the most.(2)Effects of different nitrogen treatments on soil nutrient contentUnder the experimental conditions,the total nitrogen and alkali-hydrolyzable nitrogen in the soil increased with the increase of nitrogen application rate.The total nitrogen and alkali-hydrolyzable nitrogen contents were the highest in N360 treatment,while the total phosphorus and available phosphorus,the contents of total potassium,available potassium and organic matter increased with the increase of nitrogen application rate,and the content of total nitrogen and available N was gradually decreased with the deepening of soil layer.(3)Effects of different nitrogen treatments on agronomic traits of spring maizeThe plant height,stem diameter and leaf area index of Zhengdan 958 were the highest at N270 treatment,and the plant height,stem diameter and leaf area index of Shandan 8806 were the highest at N360 treatment.Nitrogen application could significantly increase the spike of spring maize the number of spikelets,grains per spike and 100-seed weight of Zhengdan 958 and Shandan 8806 reached the maximum at the time of N360 treatment.(4)Effects of nitrogen fertilizer on spring maize yield,nitrogen use efficiency,light energy utilization,water use efficiency and net income.The yield of Zhengdan 958 increased first and then decreased with the increase of nitrogen application rate,and reached the highest yield when the amount of nitrogen was 264 kg/hm2.The yield of Shandan 8806 increased gradually with the increase of nitrogen application rate.The nitrogen application rate of Zhengdan 958 increased first and then decreased with the increase of nitrogen application rate,and reached the highest value in N150 treatment.The nitrogen use efficiency of Shandan 8806 was the highest,the increase of nitrogen application rate increased first and then reached the highest trend,and reached the highest value at N150 treatment.The utilization of light energy in Zhengdan 958 and Shandan 8806 increased with the increase of nitrogen application rate.The water use efficiency of Zhengdan 958 increased first and then decreased with the increase of nitrogen application rate,and reached the highest value in N270 treatment.The water use efficiency of Shandan 8806 increased with the increase of nitrogen application rate,the economic gain of Zhengdan 958 and Shandan 8806 increased first and then decreased with the increase of nitrogen application rate.The economic benefit of Zhengdan 958 was the highest in the amount of N for 223kg/hm2 to reach the maximum,the economic benefits of single 8806 reached a maximum at 257 kg/hm2.