Effects Of Microbial Fertilizer On Soil Nitrogen And Phosphorus Leaching And Soil Enzyme Activity And Microorganism

Biochar-based microbial fertilizer is a new type of organic fertilizer that has potential value in reducing the loss of nitrogen and phosphorus nutrients and improving the quality of acidic tea orchard soils.To investigate mechanisms of BMF on nitrogen and phosphorus leaching in acidic tea orchard soils,the pot experiment with two fertilizer types(Microbial Fertilizer and Biochar based Microbial Fertilizer)and four fertilizer proportion(20%,40%,60%,80%)was conducted,along with conventional chemical fertilizer as control(CK).The effect of different fertilization modes on the loss of nitrogen and phosphorus,the response mechanism of physical and chemical,biochemical and microbial function indexes of soil were also studied in research program.The evaluation of the effect of BMF fertilizer on tea orchard soil from the perspectives of water,soil and microorganisms were carried out and,the main points are as follows:(1)In terms of nitrogen,the two kinds of microbial fertilizer could reduce the risk of nitrogen leaching,but the reduction was affected by the proportion rate.In this experiment,both of MF-80%and BMF-60%had a better reduction of ammonia nitrogen,nitrite and total nitrogen in leachate.In the aspect of phosphorus,the two kinds of microbial fertilizer could reduce the leaching of total phosphorus and significantly reduce the total phosphorus concentration in the first leaching process after fertilization.Compared to MF fertilizer,however,BMF fertilizer had not significant influence on total phosphorus.(2)Soil enzyme activity and microbial biomass were the key factors controlling the material cycling in tea orchard soil.The two kinds of microbial fertilizer could inhibit the activity of soil urease,which reduce the rate of urea nitrogen transformation and the leaching loss of nitrate nitrogen.At the same time,they enhanced the activity of soil β-glucosidase and acid phosphatase,the availability of soil-insoluble phosphorus,and the conversion of other material cycles.They could also increase the soil pH,improve the degree of acidification of tea orchard soil.Under the same proportion rate,BMF fertilizer had stronger soil enzyme activities,microbial biomass and soil nitrogen and phosphorus than MF fertilizer.(3)The two kinds of microbial fertilizer had different influences on the bacterial community in tea orchard soils.The MF fertilizer treatment increased the abundance of the bacterial community but had no significant effect on the bacterial community composition.The three treatments(BMF-40%,BMF-60%and BMF-80%)of BMF fertilizer had a significant influence on the composition and abundance of soil bacterial community in tea orchard soils.The soil environmental factors are closely related to the microbial community and influence each other.The soil indexes affecting the bacterial community in the tea plantation mainly include ammonium nitrogen content,total nitrogen content and pH value.(4)Compared with the other treatment of MF and BMF groups,BMF-60%could better control nitrogen leaching,increase soil ammonium nitrogen content,total nitrogen content and pH value,then change the structure of the original microbial community in the acidic tea orchard soils.These advantageous bacteria groups could also participate in the transformation and utilization of dead animal and plant residues and insoluble organic compounds to improve soil quality,enrich nutrient content and adversity resistance,which is beneficial to the sustainable development of tea orchard soils.