Effects Of Reduced Chemical N Combined With Organic Fertilizer On Soil Nutrient And Microbiological Properties In Oat Field

There are few researches and reports on the interaction system of soil-microorganism-nutrient in oat field in present.It's very important to study the effect of chemical N reduction combined with organic fertilizer on the soil nutrient and microbiological properties in oat field,which has a great significance to the ecological management of oat field as a result of green and sustainable effect of chemical N reduction.Bayou18 was used and set five field treatments in this experiment: no fertilizer CK,conventional nitrogen N1(pure N 90 kg·hm-2),50% nitrogen fertilizer N2(pure N 45 kg·hm-2),and 50% nitrogen fertilizer combined with organic fertilizer N2O1 and N2O2(O1 contains a total N of 90 kg·hm-2,and O2 contains a total N of 45kg·hm-2).This experiment was conducted to investigate the effects of 50% chemical N fertilizer combined with organic fertilizer on soil nutrient and microbiological properties,furthermore,comprehensive analysis on the relationship among soil nutrient,microbiological properties and yield were carried out.The main research results were as follows:(1)In this experiment,compared to conventional N application,50% N combined with organic fertilizer had a significant inprove trend to soil organic carbon,total nitrogen,microbial biomass carbon,microbial biomass nitrogen,urease and invertase activity in oat field;a significant inprove trend to soil available N and P content at middle and late stages in oat field,also improved trend with the increasing in the amount of organic fertilizer.50% N combined with organic fertilizer had a significant decrease trend to SOC/TN and SMBC/SMBN;had no effect on q MB in oat field.However,it had a significant improve trend to SMBN/TN at early and middle stages in oat field.(2)Biolog analysis showed that there was a significant inprove trend to the utilization of the six types of carbon sources by soil microbial communities in 50% N combined with a further increasing organic fertilizer application,as well as the richness and evenness of soil microbial communities,compared to conventional N application in oat field.Biplot analysis showed that amino acids and amines were the main carbons to distinguish the difference of the metabolism characteristics on carbon sources of soil microbial community among different fertilizers.(3)Correlation analysis showed that there were significant or extremely positive correlation among soil organic carbon,total nitrogen,available nitrogen,available phosphorus,microbial biomass carbon,microbial biomass nitrogen,Shannon-Wiener index,Mc Intosh index,urease and invertase activity,also between q MB and soil total nitrogen,available phosphorus,microbial biomass carbon,microbial biomass nitrogen and urease activity.Principal component analysis showed that soil organic carbon,SMBN/TN,available nitrogen,available phosphorus,SMBC/SMBN,Mc Intosh index,urease and invertase activity were the main representative soil character indicators to induce differences among different fertilization treatments.(4)Both of the principal component analysis score and biplot analysis showed that the soil comprehensive properties on baise of nutrient and microbiological properties were excellent in 50% N combined with double organic fertilizer in oat field.(5)There was significant positive correlated between the comprehensive score of principal component analysis about soil properties and oat yield.50% N combined with double organic fertilizer with the total N of 90 kg·hm-2 could increase oat yield though the effect on soil nutrient and microbiological properties.Biplot analysis showed the result of its improve on ten soil properties including soil organic carbon,total nitrogen,q MB,available nitrogen,available phosphorus,microbial biomass carbon,microbial biomass nitrogen,three soil microbial diversity indexes,urease and invertase activity.