Effects Of Nitrogen Application On Nitrogen Utilization Characteristics And Yield Quality Of Winter Wheat With Different Former Crops

In study,a split plot experiment with two factors was conducted using wheat ‘YN211' as materials.factors in the main plots were different former crops which were sole maize,maize intercropped with soybean,sole soybean respectively,and that in the subplot were 4 nitrogen levels as N0(0 kg·hm-2),N180(180 kg·hm-2),N240(240 kg·hm-2),N300(300 kg·hm-2)respectively,to study the effects of different former crops and nitrogen application on chlorophyll content,nitrogen accumulation,dry matter accumulation,yield and its components,grain quality and Zn accumulation,soil water content and inorganic nitrogen of winter wheat.The main results are as follows:1.Water content in deep soil of winter wheat a in intercropped maize with soybean and sole soybean was higher than sole maize former crops,and nitrate nitrogen content in soil of sole soybean former crops was higher.2.At the late flowering stage,winter wheat chlorophyll a,chlorophyll b and total chlorophyll content in intercropped maize with soybean and sole soybean were higher than sole maize former crops.The content of carotenoids and chlorophyll a/b in sole soybean were higher than other two former crops.It had significant effects of nitrogen application and different former crops on dry matter accumulation in winter wheat,dry matter accumulation at jointing stage,leaf > stalk,flowering stage,stalk > glumes + rachis > leaf,7 days after flowering stage,stalk > glumes + rachis > grain>leaf,filling medium(15 days after the flowering)to mature stage,grain > stalk > glumes + rachis > leaf.3.In different former crops winter wheat jointing stage to mature stage various nutritional organs and grain nitrogen accumulation,overall increased with the increase of the N application rate,a suitable amount of fertilizer is beneficial to the accumulation of nitrogen.Under same nitrogen application levels,It showed that the agronomic efficiency and partial factor productivity(PFP)of nitrogen fertilizer was the highest in sole soybean,followed by that of intercropped maize with soybean,and that of sole maize was the lowest at the former crops treatments,which were significant at the level of N180 and N240.4.Compared with sole maize former crops,winter wheat yield significantly increased in intercropped maize with soybean and sole soybean,increased by 4.74%~10.01%?5.12%~17.05% respectively under different nitrogen levels.Different former crops had significant difference on Spike number and kernel number per spike,no significant influence on 1000-kernel weight.Compared with sole maize former crops,winter wheat Spike number increased by10%~15%,4%~19%,Kernel number per spike increased by 2%~21%,4%~20% in sole soybean,intercropped maize with soybean respectively.The nitrogen application had a remarkable effect on Spike number and 1000-kernel weight,and no difference in kernel number per spike.It had strikingly effects of interaction between different former crops and nitrogen application on grain number per spike and 1000-kernel weight.Based on the equation of analog curve N application and yield,the N application of optimum economic yield and the maximum yield in winter wheat were 243 kg·hm-2 and 262 kg·hm-2at the sole maize treatment,respectively.In sole soybean and intercropped maize with soybean,the N application of optimum economic yield was 196 kg·hm-2 and 210 kg·hm-2,respectively,and N application of maximum yield was 205 kg·hm-2 and 222 kg·hm-2,respectively.The protein content and wet gluten content of wheat at different former crops increased with the increase of nitrogen application,and there was significant difference between different nitrogen application levels.Nitrogen had little effect on the bulk density of winter wheat at sole soybean former crops,and there was no significant difference between different nitrogen application levels.