Effects Of Types Of Nitrogen Fertilizers And Nitrogen Application Rates On Corn Growth And Soil Properties

Biochar-based fertilizer was a new type of fertilizer formed by mixing and granulating biochar with chemical fertilizers.This experiment adopts a split-plot design,the main plot was nitrogen fertilizer types:urea（U）,biochar-based fertilizer（B）,and the sub-plots were five nitrogen application rates:0 kg·hm^-2（N0）,135 kg·hm^-2（N1）,270 kg hm^-2（N2）,405 kg hm^-2（N3）,540 kg hm^-2（N4）,using Zhengdan 958 as the test material,In order to explore the effect of nitrogen application rate of biochar-based fertilizer on the growth,yield and nitrogen utilization of maize,and to determine the optimal application rate of biochar-based fertilizer in the local area,it provides a theoretical basis for the application of biochar-based fertilizer in the agricultural field.The conclusions are as follows:（1）Biochar-based fertilizer promoted the growth of corn.Compared with no fertilization,the application of biochar-based fertilizer can significantly increased the leaf area index of maize,and compared with the application of urea,the leaf area index was slightly decreased.The application of biochar-based fertilizer also increased the chlorophyll content and carotenoid content of maize leaves,promoted maize photosynthesis,increased the net photosynthetic rate of maize,and increased F_v/F_m.Urea treatment,but not much difference.Compared with urea,biochar-based fertilizer also showed no significant difference in the maximum photochemical efficiency of PS‖.The nitrogen application rate of 405kg·hm^-2 had the best effect on promoted the growth of maize.（2）Biochar-based fertilizers increased the accumulation of carbon and nitrogen in corn.Nitrogen fertilization increased the dry matter accumulation at the silking and mature stages.In2021,the biochar-based fertilizers decreased the average dry matter accumulation of leaves,stems,and total dry matter at the silking stage by 11.14%,13.11%,and 12.67%,respectively,compared with the urea treatment.The total dry matter accumulation in the base fertilizer treatment decreased by 6.72%compared with the urea treatment.Compared with the biochar-based fertilizer,the average value of total dry matter transfer of corn plants in urea treatment increased by 17.29%,and the average value of contribution rate to grain increased by 16.85%,but there was no significant difference in transfer rate.Nitrogen application can significantly increased the nitrogen accumulation in various organs at the silking and mature stages of maize.Compared with biochar-based fertilizers,urea increased the total nitrogen accumulation at the silking stage and the nitrogen accumulation in stems and leaves at the mature stage.Nitrogen accumulation was not significantly affected.With the increase of nitrogen application rate,the nitrogen absorption and utilization efficiency and the partial productivity of nitrogen fertilizer both decreased significantly.（3）Biochar-based fertilizer improved corn yield and increase income.Biochar-based fertilizer increased corn yield by increased corn 100-kernel weight,number of rows per ear,and number of grains per ear.Compared with no nitrogen application,the ear length and ear diameter increased by 11.59%～27.41%and 5.83%～10.90%in the nitrogen application treatment.The number of rows,grains per row and grains per spike increased by 1.81%-10.45%,13.66%-35.28%,21.12%-48.86%,respectively,and the 100-grain weight increased by 3.03%-12.75%.In the range of 0～405kg·hm^-2,with the increase of nitrogen application rate,maize yield also increased significantly,and when it exceeded 405kg·hm^-2,the yield no longer increased significantly with the increased of nitrogen application rate,but increased A downward trend was observed,and the economic benefit reached the highest when the nitrogen application rate was 405kg·hm^-2.（4）Biochar-based fertilizer improved soil nutrient content and soil fertility.Nitrogen application increased soil total nitrogen and alkali-hydrolyzable nitrogen content.Within a certain range,soil total nitrogen and alkali-hydrolyzable nitrogen content also increased with increased nitrogen application rate,and then soil total nitrogen content decreased with increasing nitrogen application rate.When the nitrogen content was 270kg·hm^-2,the contents of total nitrogen and alkali-hydrolyzable nitrogen reached the maximum value.Compared with urea,the total nitrogen and alkali-hydrolyzable nitrogen content increased by 0.69%and 2.25%respectively,However,there was no significant difference between the treatments and N0.The application of biochar-based fertilizer also significantly increased the content of soil available phosphorus,which is 2.68%-21.36%higher than no fertilization,and 5.14%higher than the average value of urea treatment.Compared with N0,nitrogen application increased the content of available potassium.Compared with urea,the application of biochar-based fertilizer increased the content of soil available potassium by 0.96%;the application of biochar-based fertilizer increased the content of soil organic matter by 17.79%-40.87%,and the nitrogen application rate was 270kg·hm^-2 when the biochar-based fertilizer treatment reached the maximum value,the organic matter content increased by 2.51%compared with the urea treatment.