Study On Optimization Of Maize Nitrogen System Under Drip Irrigation

In order to understand the role of drip irrigation fertigation technology in grain production,to further explore the reasonable fertilization modes,this experiment taking corn as the research object studied the effect of different nitrogen quantity on maize morphological indexes,photosynthetic characteristics,nutrient and yield etc.under the fertigation conditions of Liaoning brown soil zone and further make scientific and reasonable fertilization modes.In order to achieve high quality and high yield of maize production,improve fertilizer use efficiency,give full play to the role of drip fertigation technology in food production and provide a theoretical basis for.The main conclusions are as follows:(1)When the amount of nitrogen applied was constant and the nitrogen application quantity was 75?225 kg/hm2,the plant height and leaf area index of maize increase with the increase of nitrogen application quantity,and the plant height of 225 kg/hm2 treatments increased than 175kg/hm2,125kg/hm2,75kg/hm2 and CK by 11%,16.2%%,23.9%and 28.9%.The leaf area index of 225 kg/hm2 increased than 175kg/hm2,125kg/hm2,75kg/hm2 and CK by 3.3%,8.1%,12.5%and 17.1%.The plant height and leaf area index(LAI)of maize under one nitrogen application were greater than two and three nitrogen treatments at most stages of growth.The effect of nitrogen application quantity on leaf area index was mainly at the jointing stage.During this period,a large amount of nitrogen application could significantly increase the leaf area index of maize,while the nitrogen application quantity In the late growth period of maize slow down leaf senescence,promote fruit development.(2)When the amount of nitrogen applied was constant and the nitrogen application quantity was 75?25 kg/hm2,the increase of nitrogen application quantity could improve the Pn,Gs and water use efficiency of maize leaves,and decrease the Ci.When the amount of nitrogen applied was constant,the photosynthetic capacity of leaves was higher at the early stage of maize growth,and the later photosynthesis decreased significantly.During the grain filling stage,the water use efficiency of the three treatments was 1.01 and 1.03 times higher than that of the second and one application.In the mature stage,the net photosynthetic quantity of the three treatments was high,which was 1.13 and 1.40 times of 2 times and 1 time respectively.3 times of nitrogen application can effectively retard the decrease of photosynthetic capacity at the later stage of maize growth and increase the duration of high photosynthesis of maize leaves.(3)In the whole growth period,the dry matter accumulation and nitrogen accumulation of maize increased with the increase of nitrogen application quantity when the total nitrogen application quantity was the same and the nitrogen application quantity was 75?225 kg/hm2.It was the most obvious after filling stage.When the amount of nitrogen applied was constant,the amount of dry matter accumulation and accumulation quantity of the three treatments were significantly higher than that of the 2 times and the 1 time treatment,In the filling stage,the amount of dry matter accumulation of the three treatments increased by 4.3%and 8.8%than that of the 2 times and the 1 time treatment.The effect of nitrogen application on the amount of nitrogen accumulation was less than that of nitrogen application.A large amount of nitrogen could only increase the nitrogen accumulation of maize in the short term,and could not meet the requirement of nutrient in the later stage of maize growth,which was not conducive to the absorption and utilization of the whole growth period.(4)The results showed that when the nitrogen application quantity was 75?225 kg/hm2,the yield of maize increased with the increase of nitrogen application quantity.Under the same nitrogen application quantity,the yield of 3 treatments was 5.4%and 9.5%higher than that of 2 times and 1 time.With the increase of nitrogen application quantity,the nitrogen use efficiency,nitrogen fertilizer agronomic efficiency and nitrogen fertilizer partial productivity of maize showed different degrees of decline.Under the same nitrogen application quantity,the nitrogen use efficiency,nitrogen fertilizer agronomic efficiency and the partial productivity of nitrogen fertilizer of 3 times treatments was significantly higher than that of 2 times and 1 time treatments.(5)In this study,compared with non-nitrogen fertilizer treatment,the protein,fat and starch content of maize showed an increasing trend with the increase of nitrogen application quantity.When the total N application quantity was constant,the protein content of the three treatments was 3.7%and 2.5%higher than that of the second times and one time treatment respectively.The average fat content increased by 2.1%and 2.1%respectively.The average starch content increased by 1.2%and 1.6%.(6)By means of principal component analysis,the yield and quality of maize were analyzed,and the main components were the highest when the nitrogen application patterns were T3N4 and T3N3(the number of nitrogen applied was 3 times and the nitrogen application quantity was 175-225 kg/hm2)The yield and quality of each treatment are in the optimal state.