Screening Of Azotobacteria, P-releasing And K-releasing Bacteria In Rhizosphere Of Juglans And The Studies On The Distribution Characteristic

As a non-nuisance and green fertilizer,Microbial Fertilizer could improve crop nutrition,soil fertility and accelerate the process of other life activities in soil and material transformation.They also have many characteristics such as innocuity,harmless, non-pollution,low cost and so on.In these circumstances,people have attached more and more importance to Microbial Fertilizer.Producing Microbial Fertilizer has become one of the central method to achieve green agriculture.At present,most Microbial Fertilizer and strains have been separated and filtrated from nature.Some scholars have pointed out that China should set up a national resource library of bacteria bio-fertilizer, collect the strains as a specifical resources in nature,which with a particular function such as releasing Phosphorus,releasing Kalium and fixing nitrogen.Combined with juglans production in Sichuan,The research have screened the Microbial Fertilizers strains which with a particular function such as releasing Phosphoru,releasing Kalium and fixing nitrogen from Rhizosphere Soil of Juglans in the major production areas of Juglans in Sichuan,detected the ability of strains and identified the strains which has conspicuous effect.The results as follows:(1)By screenning from the selective medium and detecting the ability of strains,the research have screened 431 strains of Microbial Fertilizer.From the number of obtained strains,decomposing organic phosphorus bacteria＞decomposing potassium bacteria＞decomposing inorganic phosphorus bacteria＞nitrogen-fixing bacteria.Their number were 134,114,94 and 89 classes separately.By measuring,there have 132 classes with better effect in the 431 strains to be the object of further study.(2)According to the target of cultivating characters,cultivating features,physiological and biochemical characteristics of microbe,the separated and purified strains of Microbial Fertilizer have been preliminarily classify and identified.For some strains with better effect,it used 16S rDNA technique to identify the level of molecular biology,and found 18 generas with 50 species.Among those,decomposing inorganic phosphorus bacterium with 8 generas,decomposing organic phosphorus bacterium 6 generas, nitrogen-fixing bacteria 7 generas,decomposing potassium bacteria 4 generas. (3) In the distribution of bacteria with various functions,decomposing organic phosphorus bacteria was most abundant,its average was 20.9588×10~5cfu/g.The followed bacteria was decomposing inorganic phosphorus bacteria.Decomposing potassium bacteria was the least,its average was 13.5632×10~5cfu/g only.The highest total biomass of Microbial fertilizer strains present to Nanjiang with pH 7.04,its biomass was 104.5765×10~5cfu/g.While the lowest in the soil with pH 8.60,its biomass was 29.4834×10~5cfu/g only.(4)In all places,the biomass of decomposing inorganic phosphorus bacteria were significant positive correlation to the soil organic matter.The biomass of nitrogen-fixing bacteria were extremely significant positive correlation to the soil organic matter.While decomposing organic phosphorus bacteria and decomposing potassium bacteria have little relevance.In the relativities of Microbial Fertilizers strains with total nitrogen,total microbes and total kalium,the biomass of decomposing potassium bacteria has significant positive correlation to the soil total kalium.Other relativities were not distinct.(5)The population diversities and enrichness of the Microbial Fertilizers strains in each place showed as follows.The population diversities and enrichness of decomposing inorganic phosphorus bacteria were higher than others in Hanyuan and Heishni.the population diversities and enrichness of decomposing organic phosphorus bacteria were higher than others in Hanyuan.The population diversities and enrichness of decomposing potassium bacteria were higher than others in Beichuan.The population diversities and enrichness of nitrogen-fixing bacteria were higher than others in Nanjiang and Xingwen.