Preparation And Screening Of Biochar Based Phosphorus Fertilizer And Its Effects On Soil Properties And Crop Growth

In agricultural production,improper disposal of livestock and poultry manure and irrational application of phosphorus fertilizer are the important factors that cause the increasingly serious non-point source pollution of agriculture in China.The utilization of livestock and poultry manure and development of new green fertilizer are of great practical significance in alleviating the pollution of non-point agricultural source and protecting urban and rural ecological environment.In this paper,cow manure biochar and traditional phosphate fertilizer(triple super phosphate)were used as raw materials,and biochar-based phosphate fertilizer 1 and biochar-based phosphate fertilizer 2 were prepared by chemical and physical methods.The effects of the two kinds of biochar-based phosphate fertilizer on different phosphorus levels of soil(phaeozem and red soil)were studied through Leaching in Soil Columns and soil culture experiment,and a better biocharbased phosphate fertilizer was screened out.Pot experiments were conducted to verify its value and potential in improving yield and quality of crop and soil quality.The main research results are as follows:(1)In phaeozem,the cumulative leaching amount of total phosphorus in the leaching solution treated with biochar-based phosphorus fertilizer 1 and biochar-based phosphorus fertilizer 2decreased by 73.52% and 37.01% compared to traditional phosphorus fertilizer,respectively;In red soil,compared to traditional phosphorus fertilizer,it has decreased by 14.20% and 8.62%,respectively.Applying biochar-based phosphorus fertilizer to black and red soil can reduce the loss of phosphorus in the soil and reduce the risk of phosphorus loss in the soil.Compared to red soil,biochar-based phosphorus fertilizer has a stronger ability to reduce the risk of phosphorus loss in phaeozem,and biochar-based phosphorus fertilizer 1 has a stronger ability to reduce the risk of phosphorus loss in both soils than biochar-based phosphorus fertilizer 2.(2)In the early stage of soil cultivation(0-28 days),the effective phosphorus content of traditional phosphorus fertilizer,biochar-based phosphorus fertilizer 1,and biochar-based phosphorus fertilizer 2 treatments showed a decreasing trend in phaeozem and red soil,decreased by 42.73%,16.80%,and 29.93% in phaeozem,and decreased by 78.31%,24.64%,and 57.53%in red soil,respectively;In the middle and later stages of cultivation(28-70 days),the effective phosphorus content of traditional phosphorus fertilizer,biochar-based phosphorus fertilizer 1,and biochar-based phosphorus fertilizer 2 treatments tended to stabilize in both soils.Among them,the average effective phosphorus content of biochar-based phosphorus fertilizer 1 and biocharbased phosphorus fertilizer 2 treatments in phaeozem was 9.47% and 9.81% higher than that of traditional phosphorus fertilizer,and in red soil,it was 129.23% and 57.53% higher than that of traditional phosphorus fertilizer,respectively.Compared to traditional phosphorus fertilizers,applying biochar-based phosphorus fertilizer to black and red soil can slow down the release rate of phosphorus in the soil and improve the effective utilization rate of phosphorus in the soil.Among them,biochar-based phosphorus fertilizer has a more significant effect on improving the effective utilization rate of phosphorus in red soil,and biochar-based phosphorus fertilizer 1 has a stronger effect on improving the effective utilization rate of phosphorus in both soils than biochar-based phosphorus fertilizer 2.(3)In phaeozem,compared with traditional phosphorus fertilizer,cherry radish treated with biochar-based phosphorus fertilizer 1 increased aboveground and root yields by 8.51% and 7.77%,respectively.Vitamin C and soluble sugar content increased by 28.71% and 16.97%,respectively,while nitrate content decreased by 6.16%.In red soil,compared with traditional phosphorus fertilizer,cherry radish treated with biochar-based phosphorus fertilizer 1 increased aboveground and root yields by 3.17% and 17.31%,respectively.The content of vitamin C and soluble sugar increased by 1.69% and 13.25%,respectively,and the nitrate content decreased by 8.79%.Applying biochar-based phosphorus fertilizer to black and red soil can improve the yield and quality of cherry radish.(4)Compared with traditional phosphorus fertilizer,the phaeozem and red soil treated with biochar-based phosphorus fertilizer 1 showed a decrease of 7.82% and 7.91% in soil bulk density,an increase of 12.55% and 10.85% in total soil porosity,an increase of 13.81% and 18.64% in average weight diameter of water stable aggregates,and an increase of 29.08% and 22.12% in average geometric diameter,respectively.Compared with traditional phosphorus fertilizer,the p H value of phaeozem and red soil treated with biochar-based phosphorus fertilizer 1 increased by0.32 and 0.26 units,respectively,the electrical conductivity increased by 2.56% and 14.81%,and the organic matter content increased by 3.89% and 35.77%,respectively.Compared with traditional phosphorus fertilizer,the two types of soil treated with biochar-based phosphorus fertilizer 1 also showed an increase in soil nutrient nitrogen,phosphorus,and potassium content,while the availability of heavy metals Pb and Cd in the soil decreased.Applying biochar-based phosphorus fertilizer to black and red soil can improve the physical and chemical properties of the soil.The above results indicate that compared to traditional phosphorus fertilizers,biochar-based phosphorus fertilizers prepared from cow manure and traditional phosphorus fertilizers can reduce the leaching loss of phosphorus in black and red soil,and reduce the risk of agricultural non-point source pollution caused by soil phosphorus loss;Moreover,biochar-based phosphorus fertilizer can slow down the release rate of phosphorus in both soils and improve the effective utilization rate of phosphorus in black and red soils.The biochar-based phosphorus fertilizer 1 prepared by chemical method(co pyrolysis)has a better effect on reducing the risk of phosphorus loss and improving the effective phosphorus utilization rate in both soils.Applying it to two types of soil can increase the yield and quality of cherry radish,while improving soil physicochemical properties.Cow manure biomass based phosphorus fertilizer has certain application potential and value in different soils,which can provide theoretical basis for the resource utilization of cow manure and the prevention and control of agricultural non-point source pollution.