| Red soil is a typical zonal soil in the hilly mountains of southern China.However,due to the low nutrient content of red soil and unreasonable exploitation and utilization in recent years,the red soil is poor and acidified,which restricts the development of red soil cultivation areas.With the rapid development of livestock and poultry industry in China,the rapid development of livestock and poultry industry has also brought a large increase in livestock and poultry waste.The waste from livestock and poultry breeding,especially the waste from pig breeding,is treated with organic fertilizer and returned to the field as a kind of organic green fertilizer,which is of great significance to the resource utilization of the waste from livestock and poultry breeding and soil improvement.On the other hand,in recent years,studies and applications of using photosynthetic bacteria to treat livestock and poultry breeding wastewater have emerged in large numbers.How to treat and recycle the surplus photosynthetic biomass produced in this process has also become an urgent problem to be solved.Based on the above three problems,this study carried out a background investigation on the soil of a grapefruit garden in Fujian and selected pig manure as the research object.The photosynthetic biological particles generated in the treatment of simulated livestock and poultry wastewater under different culture conditions were characterized and analyzed and used as bacteria additives in the process of pig manure composting.After measuring the basic physicochemical properties and microorganism of the composting products,the effects of traditional pig manure organic fertilizer and photosynthetic organism coupling pig manure organic fertilizer under different culture conditions on red soil were compared and analyzed by indoor simulated field experiments.The main research conclusions of this study are as follows:(1)Based on field sampling of grapefruit garden soil in red soil area,this study found that returning organic fertilizer from pig manure to the field could improve p H value of acidic red soil and increase the content of organic matter and nitrogen in the soil to a certain extent.On the other hand,the return of organic fertilizer from pig manure significantly affected the relative abundance of nitrogen-cycling microorganisms in red soil,and the relative abundance of microorganisms increased with soil depth.Correlation analysis results showed that p H value,water content,total organic matter and other properties of red soil were significantly correlated with nitrogen cycling flora,while Brady-Rhizobiaceae was negatively correlated with p H value and water content,while it was positively correlated with ORP.(2)Five different culture conditions R1,R2,R3,R4 and R5 were set to cultivate photosynthetic biological granular sludge,The total nitrogen ratio degradation rate of photosynthetic biological granules was R1(11.55mg/g SS)>R2(9.75mg/g SS)>R4(9.67mg/g SS)>R3(5.55mg/g SS)>R5(4.81mg/g SS)under five different photosynthetic biological granules culture conditions.And R1 culture system has the best granulation effect.Among the five culture conditions,the relative abundance of photosynthetic bacteria in R3 and R2 treatment groups was higher than that in other treatment groups.The photosynthetic biological particles obtained from R1?R5 culture were combined with pig manure compost to obtain the compost samples of T1?T5treatment groups,respectively.Compared with pig manure composting(control),the total nitrogen content in the composting products was increased after the photosynthetic biological particles were used in the composting.Microbial community analysis showed that photosynthetic biological particles coupled with pig manure composting significantly increased the relative abundance of photosynthetic bacteria in the composting products.At the order level,the relative abundance of photosynthetic bacteria in each treatment group were T3(3.62×10-1)>T4(3.07×10-1)>T2(2.8×10-1)>T1(2.61×10-1)>T5(1.67×10-1)>control(1.39×10-1),respectively.(3)The photosynthetic biological fertilizer(PBO)and pig manure organic fertilizer(control)of T1?T5 treatment groups were added into red soil,respectively,and the corresponding soil samples S1-S6 were obtained.The photosynthetic biological organic fertilizer could significantly increase the p H,organic matter and total nitrogen content of red soil,improve the living environment of microorganisms in red soil,and the improvement effect was better than that of pig manure organic fertilizer.Compared with other treatment groups,the relative abundance of nitrogen fixing functional genes in S1 treatment group was the highest,and its nitrogen fixing rate was also the highest.Physical and chemical properties were significantly correlated with microorganisms.Among them,Inorganic nitrogen and p H were significantly positively correlated with Proteobacteria,Actinobacteria,Planctomycetes,Firmicutes and other bacteria.Acidobacteria was negatively correlated with physical and chemical properties. |
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