Accumulation Of Soluble Salt And Oil In The Process Of Sludge Composting On Soil Physical And Chemical Properties And Growth Of Tall Fescue

The land use of urban sludge compost is one of the important methods for the disposal of municipal sludge.However,after soil sludge composting is applied multiple times,there will be soil compaction and deterioration of plant growth.In order to investigate the causes of soil degradation,the soluble salts and oils accumulated in the soil during the sludge compost land use were taken as the research object,and the soluble salts and oils in the municipal sludge compost were used to study the physical and chemical properties of the soil and the plants.Growth and other aspects of the impact.In this paper,by potting experiments,different amounts of soluble salts and oils were added to the potted soil to simulate the accumulation of soluble salts and oil in different top dressing times,and to study the changes in soil bulk density under different salt or oil concentrations,water content,porosity,saturated water capacity,electrical conductivity,pH,organic matter,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus,available potassium,total number of bacteria,etc.Soil physical,chemical,and biological indicators,and potted grass height,biomass indicators and the effects of soluble salts and oils in urban sludge compost on soil physical and chemical properties and plant growth.The study found that in the 17th week of the experiment,when soil salt content increased from 0.6%to 1.2%,the bulk density increased by 5.2%,the porosity decreased by 3.78%,the compaction increased by 31.2%,and the effective nitrogen and available phosphorus respectively decreased by 24.8%and 15.1%,the total number of bacteria decreased by 58.5%,and the biomass decreased by 23.2%.This shows that the soluble salts in municipal sludge compost will lead to soil compaction,threaten the survival of soil microorganisms,inhibit the organic mineralization of soil,reduce the content of available nitrogen,available phosphorus and available potassium,and reduce the available nutrient content required for plant growth,and affect plant growth.With the increase of oil content,soil bulk density,porosity,pH,electrical conductivity,compactness and other indicators did not change significantly,indicating that the oil in the municipal sludge compost had no significant effect on soil physical properties.However,the soil organic matter mineralization rate decreased with the increase of oil content.The content of soil available nitrogen,available phosphorus and available potassium and the total number of bacteria increased first and then decreased with the increase of oil content.In the 17th week of the experiment,the refueling The amount increased from 0.0 g to 3.0 g,the soil available nitrogen and available phosphorus content decreased by 22.4%and 26.2%respectively,and the biomass of tall fescue decreased by 12.6%.This shows that a small amount of sludge composting oil does not affect soil microbial activity and plant growth,and that top dressings with more than three accumulated oils will inhibit the growth of soil microorganisms and plants,and plant height and biomass increase first with oil content,then decreasing.This trend also verifies the previous conclusion.