Effects Of Nitrogen Application Rate On Growth, Yield And Quality Of Winter Wheat In Weibei Dryland

Rational nitrogen application in dryland wheat can improve the efficiency of precipitation utilization and increase production and increase efficiency.In order to change the long-term unreasonable fertilization of wheat fields in the Weibei dryland,to achieve stable and efficient use of limited rainfall in dry land,and to continuously improve the ability of wheat field to resist drought and increase production,this experiment was carried out in2017-2018 at the Ganjing Experimental Station in Heyang,Shaanxi Province.The field nitrogen application and the two-factor rifting zone test were carried out with 5 nitrogen treatments at 0,60,120,180,240 kg/hm~2(represented by N0,N1,N2,N3,and N4,respectively).Uniform application of phosphate fertilizer 120 kg/hm~2,with potassium fertilizer 90 kg/hm~2.The tested varieties were selected from Jinmai 47 and Chang 6359,and a total of 30 nitrogen application and variety combination plots were set up.Based on the data of wheat growth in a single season,this paper compared the effects of different nitrogen application rates and variety treatments on winter wheat population growth,yield,quality,fertilizer utilization,water use efficiency(WUE),etc.,aiming at efficient water and fertilizer management for winter wheat in dry farming.The measures provide theoretical basis and practical experience.The main findings are as follows:(1)Effects of different nitrogen application rates on soil moisture content in dryland wheat fields.Nitrogen application significantly affected the water consumption during the growth period of winter wheat.The water consumption of Chang 6359 and Jinmai 47 was inversely proportional to the increase of nitrogen application gradient,and the water consumption was the lowest under the highest nitrogen application rate.The most water-consuming period of the two varieties of winter wheat is from jointing to flowering.To the flowering period,the most water-consuming treatment is N3 treatment with a length of 6359.The soil 200 cm water storage is reduced by 133.71 mm.The treatment with the least water consumption is N1 of Jinmai 47,and the soil 200 cm water storage is reduced112.01 mm;the water use efficiency of winter wheat grain yields in both varieties showed a parabola change with the increase of nitrogen application gradient,and the water use efficiency reached the maximum under the treatment of N3.This indicates that fertilization has obvious water transfer effect,moderate nitrogen fertilizer can significantly improve grain water use efficiency;the water consumption of Chang 6359 under each nitrogen fertilizer gradient is greater than that of Jinmai 47,only from the perspective of yield and water use,The N3 treatment of Jinmai 47 has high yield,high water use efficiency and low water consumption.(2)Effects of different nitrogen application rates on soil nutrient content during winter wheat harvest.The amount of nitrogen applied significantly improved soil mineral nitrogenn and organic matter content.With the increase of nitrogen application rate,the mineral nitrogenn content of the two winter wheat varieties increased significantly in the 0-20 cm soil layer during the harvest period(P<0.05),but there was no significant difference in the total nitrogen content.The average nitrogen content of the soil of the variety Jinmai 47 was slightly higher than that of the variety 6359,and it was not proportional to the nitrogen application gradient,indicating that the high nitrogen application had no significant effect on the total nitrogen content of the soil;the organic matter content and the nitrogen application gradient showed a positive correlation,and the difference between the different treatments was significant.The mean value of two varieties 0-60 cm organic matter reached the highest under N3 treatment and the lowest under N0 treatment.The available nutrients and total nutrient content of winter wheat were significantly smaller with the depth of the soil layer,the highest surface layer and the lowest bottom layer.(3)Effects of different nitrogen application rates on nutrient absorption and agronomic traits of winter wheat.The dry matter accumulation of winter wheat continued to increase with the growth period.Compared with the variety 6359,the dry matter accumulation of Jinmai 47 in the four growth stages was 3.1%,2.3%,2.1%and 3.9%higher respectively.The dry matter accumulation of winter wheat was significantly affected.That under nitrogen application at different growth stages was 19.7%,35.6%,34.6%and 21.6%higher than that of no nitrogen application,indicating that nitrogen application could significantly increase dry matter accumulation of winter wheat within a reasonable range.The amount,but exceeding the N3 gradient,does not significantly improve the dry matter,and even causes a reduction effect;the nitrogen content of the plant is significantly different under the same nitrogen treatment in the same period,except for the flowering stage,the highest content of nitrogen was in N4 treatment,which indicated that the application of nitrogen fertilizer could significantly increase the nitrogen content of plants.The chlorophyll content of wheat leaves under different nitrogen treatments was significantly different at flowering stage,and both varieties showed N4>N3>N2>N1>N0,indicates that nitrogen fertilizer has a significant effect on chlorophyll content;photosynthetic characteristics have slightly different responses to nitrogen application rate,and the determination of two growth stages indicates that nitrogen application rate have a very significant improvement to photosynthetic rate and transpiration rate(P<0.01),and a significantly reduced on carbon dioxide(P<0.01).(4)Effects of different nitrogen application rates on nitrogen use efficiency,yield and economic benefits of winter wheat.The nitrogen uptake of winter wheat increased firstly and then decreased with the increase of nitrogen application rate,indicating that nitrogen application could significantly increase nitrogen accumulation in winter wheat,but excessive inhibition could inhibit nitrogen uptake by wheat.Within the range of 0-180 kg/hm~2 nitrogen application,the number of spikes and grain number of both varieties of winter wheat showed an increase with the increase of nitrogen application rate,but the 1000-grain weight was reversed;the net output value of both varieties reached under the treatment.The highest value is 5209 and 8983 yuan respectively,so the best economic treatment is N3.In terms of variety,Jinmai 47 is better than Chang 6359;the nitrogen application rate of two varieties of winter wheat is dependent variable,and the yield is from Variables,the fitting equation of nitrogen application rate and yield was obtained.The equation showed that the length of6359 and Jinmai 47 reached the highest yield under the nitrogen application rate of 170kg/hm~2 and 192 kg/hm~2,respectively.(5)Effects of different nitrogen application rates on grain processing quality of winter wheat.Within the range of 0-180 kg/hm~2 nitrogen application in wheat field,grain protein content,wet gluten,water absorption,starch,sedimentation value,prolonged stabilization time and formation time increased with the increase of nitrogen application rate,but flour rate did not correlate with the amount of nitrogen applied,and the bulk density was negatively correlated with the amount of nitrogen applied.After more than 180kg/hm~2,except for the dough formation time,the other quality parameters decreased.In summary,N3 nitrogen treatment can significantly improve the water status,nutrient absorption,light energy utilization and fertilizer utilization rate of winter wheat field,and increase yield and income.According to the comprehensive application of nitrogen application efficiency,the recommended nitrogen application rate is 170-190 kg/hm~2.