Effects Of Pig Manure Application On Soil Physical And Chemical Properties And Microflora Composition

Based on the combination model of planting and feeding,this study studied the effect of applying pig manure on the physical and chemical properties of planting plot.The changes of physical structure,nutrient content and microbial composition of apple planting and corn-wheat rotation land with different application years and different soil depths were analyzed repeatedly,then the basic parameters for better reclaiming of manure where provided.Experiment 1:This experiment studied the effect of pig manure on the composition,physical and chemical properties of soil in apple planting plots.The apple planting plots with11 and 5 years of continuous application of pig manure water were selected as the experimental group,and the apple planting plots to which the fertilizer was applied were used as the control group.Soil samples from surface layer(0-20cm),middle layer(20-40cm)and deep layer(40-60cm)were collected to determine their physical properties,nutrient content and microbial composition.At the same time,apple samples from corresponding plots were taken to determine the apple quality indicators.The results showed that the soil bulk density and specific gravity of the apple manure water plot decreased,the porosity increased significantly(P<0.05),the soil pH decreased significantly(P<0.05),and the soil organic matter level increased significantly(P<0.05).The application of pig manure water significantly increased the contents of soil total nutrients;total nitrogen,total phosphorus and available nutrient alkali nitrogen,nitrate nitrogen,available phosphorus and available potassium.The total nitrogen content of soil for 11 and 5 years of continuous application of pig manure was increased from 15.4%~91.6% and 49.4%~125%respectively compared with the fertilizer application group.The total phosphorus also increased from 46.4%~148.6% and30.4%~166.2%;the soil alkaline nitrogen and available phosphorus increased slightly,nitrate nitrogen and available kalium has a large increase,the maximum increase of nitrate nitrogen is 300.4%,and the effective potassium in soil for 11 and 5 years of continuous application of pig manure increased by 118.6%~141.7% and 163.4%~258.5% respectively.The applicationof pig manure water significantly increased the content of Cu and Zn in apple soil(P<0.05).Compared with the fertilizer application group,the soil surface Cu content in pig manure water increased by 82.4% and 94.5%,respectively,in 11 and 5 years.The Zn content was increased by 116.5% and 145.5%,respectively.The application of pig manure water in apple plot changed the soil microbial population structure and abundance,and the abundance of Chloroflexi and Firmicutes bacteria in the soil where pig manure was applied was greatly increased,while the Actinobacteria and Acidobacteria bacteria Abundance declined to varying degrees.The application of pig manure water significantly increased the hardness and soluble solid content of apple,decreased the acidity of apple(P<0.05),and improved the quality of apple.Experiment 2: This experiment was carried out to determine the effect of application of pig manure on soil composition,physical and chemical properties of corn planting plots.The corn planting plots with continuous application of pig manure for 7 years were selected as the experimental group,and the corn planting plots with fertilizer application were used as the control group.Soil samples of surface layer(0-20cm),middle layer(20-40cm)and deep layer(40-60cm)were collected to determine their physical properties,nutrient content and microbial composition.At the same time,corn samples of each plot was taken to determine the corn quality index.The results showed that soil pH of continuous application of pig manure for 7 years was only significantly lower in the soil layer than in the fertilizer group by0.17,and the organic carbon content was increased by 56.9%~91.0%.The physical properties of the soil did not change significantly.The total nitrogen and total phosphorus in the soil with continuous application of pig manure for 7 years were significantly higher in the deep layer than in the fertilizer group.The content of available nutrients in the soil,such as alkali nitrogen,nitrate nitrogen,available phosphorus and available potassium,was significantly increased.The content of Cu in soil with continuous application of pig manure for 7 years increased by 39.7%~91.6%.Zn only increased significantly by 62.4% in the soil surface.The abundance of sphingosine bacteria was significantly improved,which greatly improves the soil's ability to utilize organic matter especially aromatic hydrocarbons which promotes nutrient cycling in the soil.Zn increased significantly in corn kernels and straw,increasing by20.5% and 32.0%,respectively.The Cu content in the straw increased by 40% however,nosignificant change was observed in the corn kernels.In summary,compared with the application of chemical fertilizers,long-term application of pig manure water in apple and “corn-wheat” rotation plots improved soil structure,increased soil organic matter,macronutrients,available nutrients,and increased soil microbes.The abundance and diversity of the crops have a certain improvement in crop quality,however,the long-term application of pig manure water caused an increase in the content of Cu and Zn in the soil,which may cause the accumulation of heavy metals in the soil and crops.