Effects Of Partial Replacement Of Chemical Fertilizer By Organic Manure On Functional Diversity Of Microbial Community In Potato Rhizosphere

In central Gansu province along the Yellow River irrigation area was Gansu province and the northwest region’s largest processing potato production base. Long-term excessively chemical fertilizers to the soil microflora and was greatly damaged biological activity and crop yields,yield mainly depend on used chemical fertilizer. The study used the method to "field trials- dilution plate culture method-modern biotechnology- Biolog Eco plate". CF(chemical fertilizer) combined with the ordinary organic fertilizer(OF) and biological organic fertilizer(BOF) partial replacement CF to researched different growth period the number of culturable microorganisms, microbial biomass carbon, microbial quotient and the influence of functional diversity of microbial community in the harvest period of potato rhizosphere. The aimed to help the reasonable fertilization for potato production in this region, the improvement of soil microflora, and provided soil biological activity. Field experiment had 10 treatments, as follows:T1:no fertilizer(CK)T2:100%(CF)T3:90%CF+3000kg /hm2(OF)T4:90%CF+3000kg /hm2(BOF)T5:80%CF+3000kg /hm2(OF)T6:80% CF +3000kg /hm2(BOF)T7:70%CF+3000kg /hm2(OF)T8:70% CF +3000kg /hm2(BOF)T9:3000kg /hm2(OF)T10:3000kg /hm2(BOF)The main results as follows:(1) Compared with the chemical fertilizer treatment(T2), all organic manure replaced part of fertilizer obviously changed the soil microbial community composition of the potato rhizosphere, to increase the number of rhizosphere bacteria IV and actinomycetes, reduce the amount of fungi and increase the ratio of bacteria/fungi and actinomycetes/fungi. The treatments of organic fertilizer replaced part of the fertilizer, the most significant number of microbial is 80% chemical fertilizer + 3000 kg /hm2 of bio-organic fertilizer. BOF partly instead of CF than OF instead of CF promoted the number of bacteria and actinomycetes, reduced the amount of fungi. Different treatment at different growing stages had a different microbial quantity change. Number of bacteria and actinomycetes in starch accumulation stage and tuber bulking stage to achieve the most, respectively. But the number of fungi in starch accumulation period is least. That results showed that organic manure fertilizer replaced parts of chemical fertilizer could regulate soil microflora structure along the Yellow River in the irrigation area in central Gansu province.(2) Compared with CF, organic fertilizer instead of part of the chemical fertilizer treatment significantly increased the potato rhizosphere microbial biomass carbon and microbial quotient, it showed that CF partial replacement of organic fertilizer can improve the soil fertility.(3) CF by partial replacement of organic fertilizer improved soil microbial activity, changed the metabolism of carbon source types, strengthen the function of potato of rhizosphere microbial community diversity. Compared with fertilization of chemical fertilizer treatment(T2), CF by partial replacement of organic fertilizer treatments improved AWCD(average pore color change rate), application of biological organic fertilizer processing is higher than ordinary organic fertilizer, to replace 20% chemical fertilizer treatment with biological organic fertilizer(T6) maximum; the main use of carbon source type consists of carboxylic acids and carbohydrates substance amines and amino acids, biological organic fertilizer instead of part of the processing of chemical fertilizer utilization rate of carbon source is relatively high and ordinary organic fertilizer; CF by partial replacement of organic fertilizer to improve fertilizer Shannon index and Mc Intosh, reduced the Simpson index.(4) CF by partial replacement of organic fertilizer on potato yield research showed that: compared with CF, no fertilizer and organic fertilizer treatments were significantly decreased in the potato production; CF by partial replacement OF or BOF treatments organic potato yield difference was not significant, 3000 kg/hm2 OF or BOF instead of 10%, 20% and 30% CF and used to find local processing of potato yield difference was not significant, and were 6% and 12% higher than the single fertilizer. That CF by partial replacement of organic fertilizer can provide adequate nutrients, guaranteed potato growth period of nutrient needs, to ensure high yield.Above all, organic fertilizer replaced part of the chemical fertilizer, especially the bio-organic fertilizer, organic fertilizer significantly altered the structure of soil microflora, and increased the microbial biomass carbon, thus improved the soil microbial metabolic activity and the amount of metabolism of carbon source, eventually improved the function of soil microbial diversity.