Effects Of Nitrogen Cycle Character On Corn And Tobacco Crop Rotation System In Guizhou Yellow Soil

Corn and flue-cured tobacco planting were widely distributed in guizhou province in southwest China,and had important significance for the sustainable development of national economy of our country.This test was Nitrogen cycle in order to define the rotation and fertilizer on Corn and Tobacco Crop Rotation System of Yellow Soil,and proved its nitrogen balance characteristics.In this paper,an experiment was conducted at Longgang Long-term Nutrient Research Station on Guizhou Province in 2016.Test set five treatment processes:no fertilizer（CK）;common fertilizer（CF）;chemical fertilizer+organic fertilizer（OF）;common fertilizer+continuous cropping（CC）;fertilizer+bio-organic fertilizer（BF）.Therefore,the experiment was designed to study the variation features of ammonia volatilization,N₂O emission,nitrogen leaching and fertilizer nitrogen uptake characteristics,etc in corn-growing season and tobacco-growing season and analyze the impact of nitrogen balance of farmland soil-crop systemsafter application of rotation and fertilizer types.The main results were as follows:1.Crop rotation treatment were higher than continuous cropping treatment respectively for19.97%and 43.10%to the amount of total dry matter accumulation for fertilization of chemical fertilizer in corn fields and tobacco fields.Conventional fertilizer+organic fertilizer+rotation cropping treatment are able to improve maize yield output and reduce the flue-cured tobacco yield output under the condition of crop rotation compared with continuous cropping.2.Corn and flue-cured tobacco farmland was 15 d after each fertilizer have emissions of ammonia volatilization during peak appeared.The processing of corn second phase according to basal and flue-cured tobacco was ammonia volatilization loss highest period,between 2.188³.625 kg.hm^-2,and 2.143².188 kg.hm^-2.Conventional fertilizer+continuous cropping is highest respectively 9.848 and 7.797 kg.hm^-2for total ammonia volatilization cumulant in corn fields and tobacco fields,and higher than that of conventional fertilizer+rotation 1.25 times and1.20 times.Therefore,conventional fertilizer+rotation can reduce corn and flue-cured tobacco soil ammonia volatilization.3.Corn and flue-cured tobacco farmland was 11 d after each fertilizer have emissions of N₂O emissions during peak appeared.Scope of the treatment of N₂O emissions were 0.19².18kg·hm^-2and 0.34⁸.72 kg·hm^-2at corn and flue-cured tobacco throughout the growing season.The application of organic fertilizer and biological organic fertilizer corn and flue-cured tobacco farmland N₂O emissions was higher,followed by conventional chemical fertilizers+continuous cropping treatment.Continuous cropping processing corn and flue-cured tobacco farmland N₂O emissions were higher than rotation handle 5.50 times and 1.05 times under the condition of the conventional single fertilizer.Therefore,conventional fertilizer+rotation can reduce corn and flue-cured tobacco soil N₂O emissions.4.Routine fertilizer+rotation treatment is to improve the utilization rate of nitrogen fertilizer in corn fields and tobacco fields.Routine fertilizer+rotation was higher than conventional fertilizer+organic fertilizer+rotations were respectively for 48.87%and 80.63%,and higher than that of conventional fertilizer+continuous cropping were respectively for131.40%and 59.34%in corn fields and tobacco fields.Different kinds of organic fertilizer can increase soil corn and flue-cured tobacco in the whole growing season nitrogen mineralization,and continuous cropping system can increase the whole growing season of corn in the soil nitrogen mineralization,and rotation cropping system can increase the amount of flue-cured tobacco throughout the growing season in the soil nitrogen mineralization.Three kinds of different fertilization treatment was not significant to nitrogen mineralization promoting rate for crop rotation at seasonal in corn fields and tobacco fields.Rotation treatment is higher than the continuous cropping,show significant difference for fertilization of chemical fertilizer in corn fields and tobacco fields.Therefore,the conventional fertilizer+rotation can be conducive to raise the utilization ratio of nitrogen and nitrogen mineralization in corn fields and tobacco fields.5.OTU of fertilization of chemical fertilizer is the highest number of 138 and 138respectively for continuous cropping in corn fields and tobacco fields.Each processing corn soil microbial diversity was not closely related with soil nitrate nitrogen content.Flue-cured tobacco soil microbial diversity was closely related with soil nitrate nitrogen content.these were closely related to the content of abundance of Alphaproteobacteria and soil nitrate nitrogen content that wereeach processing NosZ gene unique OTU species in the microbial diversity and composition of microbial outline levels.Common fertilizer+continuous cropping treatment is beneficial to keep the number of endemic species,and can reduce the impact on microbial diversity of Nos Z gene.in corn fields and tobacco fields.6.Nitrogen fertilizer inputs and soil nitrogen mineralization was a major entry of nitrogen,and crop absorption of nitrogen was a major output of nitrogen was taken away at seasonal in corn fields and tobacco fields.The Nitrogen input items are higher than Nitrogen output item in rotation and fertilizer types of nitrogen balance of each processing system.Increase organic fertilizer treatment of nitrogen balance values are the highest for crop rotation at seasonal in corn fields and tobacco fields.Impact of continuous cropping treatment nitrogen balance value is higher than crop rotation treatment for 1.06 times for fertilization of chemical fertilizer in corn fields.Impact of crop rotation treatment nitrogen balance value is higher than continuous cropping treatment for 0.23 times for fertilization of chemical fertilizer in tobacco fields.Therefore,common fertilizer+continuous cropping treatment is more reasonable for nitrogen balance value in corn fields and tobacco fields.In conclusion,crop rotation system was advantageous to the soil nitrogen mineralization and promote crop growth,and increase crop yield and reduce farmland N₂O emission,and ammonia volatilization,and reduce the soil microbial diversity Nos Z gene,and achieve the most reasonable nitrogen balance on yellow soil corn fields and flue-cured tobacco fields under the condition of the conventional fertilization.