The Amino Acid And Microbial Mechanisms Underlying Enhanced Horticultural Soil Fertility By Feather-based Organic Fertilizer

China is an agricultural country.Agriculture plays a very important role in China's national economy.Fertilization is one of the main practices for agricultural production.It has far-reaching effects on soil quality and sustainable soil use.Long-term fertilization can change soil physical and chemical properties and biological activity,and affect crop yield.In production,organic fertilizers made from feathers and mushroom residue have significant effects on bananas,oranges and so on.The organic fertilizer has a high amino acid content,and the total amino acid content is 5.12%,which is about 5 times that of other organic fertilizers in the market(about 1% amino acid),and it has an obvious effect on increasing the yield of various crops.In previous studies,research on amino acid mainly focuses on free amino acids in the soil.Recently,studies on soil adsorption of organic nitrogen,especially amino acid nitrogen distribution characteristics,bioavailability and nutrient regulation mechanism,have gradually attracted researcher's attention.There is little research regarding the regulation of soil amino acid on the structure and functioning of soil microbial communities.Therefore,the purpose of this study was to explore whether feather-based organic fertilizer can promote plant growth by regulating soil microbial community structure and functioning via amino acids.The main results of this study indicate that:(1)The application of feather-based organic fertilizer(OF)increased significantly not only the nutrient content and soil p H of lettuce,but also the content of most hydrolyzed amino acids in soil,and the activity of soil urease and soil cellulase.Therefore,the abundance and diversity of microbial community were increased,eventually achieving the goal of lettuce production increase.Compared with OF treatment,the biomass of OF plus chemical fertilizer treatment(CF+OF)was 1.5 times that of OF treatment,and the soil nutrient content,hydrolyzed amino acid content,most soil enzyme activity,microbialabundance and diversity in CF+OF treatment were higher than those of OF traetment.This indicates that there may be a ‘priming effect' of the trace chemical fertilizer,that is,a small amount of chemical fertilizer can stimulate the activity of some functional microorganisms in the soil,thereby rapidly decomposing the organic matter in the organic fertilizer and achieving the rapid growth of the plant.(2)Similar to the lettuce experiment,the Poncirus trifoliata L.,experiment showed that the application of organic fertilizer could also regulate the soil microbial community structure,and the biomass of Poncirus trifoliata L.,was increased,and the combined effect of organic fertilizer and chemical fertilizer was the best.Organic fertilizers were found to significantly increase soil urease and cellulase activity in both experiments.(3)Application of OF and certain amino acids to the soil significantly increased a variety of soil enzyme activities,soil microbial abundance and diversity,which confirms that amino acids participated in the regulation of soil microbial community structure.In this study,it was found that Phe treatment is more prominent than other amino acid treatments and it was an important factor influencing the regulation of soil microbial community structure.(4)Under field conditions,feather-based organic fertilizer showed no growth-promoting effect compared with peanut bran.The main reason may be that peanut bran is also rich in amino acids,and there were many other uncertain factors in the field.The actual effect in production needs further study.