Study On Application Of Garden Waste Compost In Soil Improvement Of Greenhouse Vegetable

Garden waste refers to the branches,fallen leaves and other plant residues generated when garden plants are naturally withered or pruned by gardeners.It has become the second largest city solid waste in China and often causes environmental pollution due to its incineration and disposal.On the other hand,the greenhouse cultivation of horticultural crops is developing rapidly in China.However,in the continuous greenhouse cultivation,irrational fertilization methods such as partial application of chemical fertilizer often lead to problems such as insufficient soil organic matter,deterioration of soil physical structure and soil acidification.Whether the garden waste can be used to improve the physical and chemical properties of greenhouse soil after composting and fermentation is still lacking.In this study beech tree and phoenix tree branches and leaves,and goldenrain tree branches and leaves were used for garden waste,through the different types of forms after fermentation finished compost,in greenhouses in long-term continuous cropping soil of watermelon and strawberry and watermelon crop rotation soil as the research object,a pot experiment was carried out to evaluate the effect of different types of garden waste compost and different application amount on soil properties,aims at to solve the problem of environmental pressure of garden waste,at the same time to improve the quality of greenhouse soil to provide a certain scientific basis.The main results and conclusions of this paper are as follows:（1）The soil bulk density decreased from 1.22 g/cm³to 1.03 g/cm³with the increase of garden waste composting from 10%to 40%.The total porosity increased from 52.70%to 59.60%,and the field water capacity increased from35.75%to 47.34%,physical properties were improved.The total porosity of beech branches was 80.07%,which was significantly higher than that of leaves of goldenrain tree,beech leaves,phoenix branches and phoenix leaves.The effects of the same garden waste compost on the physical properties of different soils were also different.The bulk density of soil in rotation was less than that in continuous cropping,while the total porosity was higher than that of continuous cropping soil.（2）The soil EC value increased from 335.42μs/cm to 528.40μs/cm with the increase of garden waste compost from 10%to 40%.Organic carbon content increased from 14.15 g/kg to 25.41 g/kg.The chloride ion content decreased from 228.47 mg/kg to 157.30 mg/kg,and the soil chemical properties were improved.The total nitrogen content of soil mixed with phoenix branches and leaf compost was higher than that of beech branches and leaf compost.The contents of alkali-hydrolyzed nitrogen and total potassium were lower than the latter.After composting,the average pH value of continuous cropping soil was increased from 5.18 to 5.70,which effectively alleviated and inhibited the trend of soil acidification.（3）With the increase of compost application amount,soil enzyme activity and aboveground biomass of vegetables also increased.The activities of urease and alkaline phosphatase in the four gradient treatments were also increased from 10%to 40%,which were 76.99%～202.36%and 15.17%～52.95%higher than those in the control treatment without compost,respectively.The soil urease activity of the leaf compost from phoenix.From the above ground biomass index of vegetables,the four application gradients were 38.87%～204.69%higher than the control.When the compost application amount was30%,the maximum biomass was 284.04 g/m².Among the four different types of compost of branches and leaves of beech and phoenix,the leaf of phoenix compost had the highest biomass.（4）The analysis of the main physical and chemical indexes affecting the aboveground biomass of vegetable crops in the process of garden waste composting showed that the total porosity,field water capacity,nutrient content and NO₃^-content were significantly positively correlated with the biomass（P<0.01）.EC value was significantly positively correlated with biomass（P<0.05）.There was significant negative correlation between bulk density and biomass（P<0.01）.Na⁺,Cl^-and SO₄^2-contents were significantly negatively correlated with biomass（P<0.05）.