Effect Of Biochar On Soil Microflora Associated With Phosphorus And Potassium

Phosphorus and potassium as two of the most important nutrient elements play a role in promoting crop growth. With the development of agriculture in China, phosphorus and potassium have received more and more attention. So the measures how to efficiently use phosphorus and potassium of is very necessary to find out. Large amounts of soil microorganisms have varying degrees of phosphate-solubilizing ability, the microbes have capable of decomposing phosphorus compounds are referred to as phosphate solubilizing microorganisms (PSM). Biochar application to soil can bring beneficial effects include: improved soil structure, increased nutrient retention, improved mineralization of organic P, and promoted growth, quality and quantity of plant. These effects may be mediated by changes to soil properties, such as soil pH, moisture retention, soil microbial biomass and activity. We hypothesized that changes in soil properties could alter microbial community structure and abundance soil enzyme activity of PSMs. In this study, tree experiments was designed to inspect changes in soil physicochemical parameters and microbial ecology in the presence and absence of biochar.A continuous cropping of corn plots experiment was set up for the no fertilizer, NK fertilizers and NPK fertilizers which were amended with corn stoverbiochar (Chinese patent: 2007 10086505) or not. A 9 weeks microcosm incubation experiment was set up for the red, brown and saline soils which were amended with rice husk biochar(400℃,0.5h) at amendment rates of 0,10,20 and 40t/hm2. A bacterial culture experiment was set up for examing the influence of biochar on the cell growth and the potassium-solubilising activity of Bacillus mucilaginosus AS 1153.The experimental results show that phosphate fertilizer could significantly increase the soil Olsen-P. Potassium fertilizer could significantly increase the soil available potassium. Corn stoverbiochar could significantly increase the phosphorus and potassium content in corn stalk and grain, soil pH, moisture, soil Olsen-P, available potassium, microbial biomass carbon, microbial biomass phosphorus and the phosphatase activities. In addition, Biochar and different fertilizer treatments could significantly impact the soil microbial diversity and community structure. Rice husk biochar could significantly adjust the pH of the three studied soils by 0.1-0.2 pH units, and increased the moisture of the three soils by 0.3-1.4% compared with the controls. The addition of biochar significantly enhance the soil Olsen-P, available potassium, microbial biomass carbon, microbial biomass phosphorus and the phosphatase activities. Generally, the soils under 20 t/hm2 biochar amendment rate demonstrating the greatest variation. Bacterial communities were investigated in all three soils using the Illumina MiSeq pyrosequencing to make tentative taxonomic assignments that showed statistically significant change over time. The consequence of the heat map with the PCA analyses suggested that the biochar shaped the bacterial community structure of the three soils to a same trend, but not for a long time. The impact of biochar on bacterial community structure of red soil is the most significant. The biochar increased the percentage of Thiobacillus in all three studied soils, Pseudomonas in the red and saline soils and Flavobacterium in the red soil, which were reported phosphate solubilizing bacteria (PSB) genera. Despite its short-term effect, it might suggested that biochar had positive effect on PSB. The bacterial culture experiment which was set up to examine the influence of biochar on the cell growth of Bacillus mucilaginosusAS 1153 show that the impact on cell growth is related to the biochar-derived feedstocks. Both intrinsic features and exterior component fraction can promote the cell growth of B. mucilaginosus AS 1153. The experimental results suggested that the biochar containing B. mucilaginosus could be used as a potential biofertilizer to sustain crop production.In conclusion, Biochar could significantly impact the properties of red soil, brown soil and saline soil, such as pH and moisture retention. It shaped the bacterial community structure of the three soils to a same trend, but not for a long time. Despite its short-term effect, it might suggested that biochar had positive effect on PSB in order to promote the availability of soil phosphorus and potassium, and phosphorus and potassium absorption of maize.