Study On Decomposition,Water Holding And Soil Permeability Of Common Garden Plant Litter

With the increase of urban impervious underlying surface,surface runoff can not be reduced in time,which is easy to cause urban waterlogging.Landscape plants and soil are important elements of landscape planning and design,which play an important role in reducing surface runoff.This paper studies the decomposition characteristics,water holding characteristics,water loss characteristics of 21 kinds of plant litter in campus and the impact of litter on soil permeability It provides basic data and theoretical reference for improving the natural ecological process of rainwater utilization of urban green space and strengthening the health of urban green space water ecosystem:(1)In the whole litter decomposition,the overall residual rate of litter decreased with the increase of time,especially in the first three months of decomposition.At the same time,the mixture of litter and the increase of its species and quantity will promote the decomposition of litter.Olson model was used to predict the decomposition rate and turnover period.The decomposition rate of litter was 0.245-1.601,1.87a-12.24a when the decomposition rate was 95%.The time of single litter is longer than mixed litter.(2)In the water holding experiment,the average value of the maximum water holding rate of 21 kinds of single litter is between 148.66%and 338.23%,while the mixed litter is between 210.79%and 294.25%.In the experiment of water loss,the average water loss rate of single litter is 170.18-308.39%,while that of mixed litter is 187.85-270.11%.Through the analysis of the difference between the maximum water holding and water loss rate,the mixed litter has better conservation performance than the single litter.The relationship between the maximum water holding rate and the water loss rate is logarithmic,which indicates that the maximum water holding rate of most plants is high,while the water loss rate is also high;the relationship between the litter water loss rate and the water loss time is logarithmic,and the relationship between the water loss rate and the water loss time is power function.(3)5.The initial permeability and stability rate of vegetation type soil are between 0.46-2.50mm/min and 0.3lmm/min-1.57mm/min,and are basically stable within 40-120min.The order of the whole infiltration rate was:arbor>shrub>shrub>grass>arbor>grass.The initial infiltration rate and stable infiltration rate of soil have a significant negative correlation with soil bulk density,and the initial infiltration rate of soil non capillary porosity has a significant positive correlation with external factors that also have a certain impact on the permeability.The purpose of improving the permeability can be achieved by enriching the vegetation structure and increasing the types and quantity of vegetation.On the basis of litter decomposition and water holding effect,it is concluded that Loropetaluw chinense var.rubrum、Cinnamomum czmphora+Photinia serrulata Lind1、Ginkgobiloba、Photinia serrulata Lind1、ynodon、山 Michelia maudiae、Koelreuteria paniculata、Liquidambar formosana+Firmiana platanifolia、Castanea mollissima、Camptotheca acuminata、Chimonanthus、Ophiopogon japonicus、Paulownia 12 tree species have strong decomposition ability,while Pseudolarix amabilis、Liquidambar formosana+Firmiana platanifolia+Celtis sinensis、Paulownia、Loropetalum chinense var.rubrum)、Michelia maudiae.Firmiana platanifolia+Cinnamomum czmphora、Liquidambar formosana+Osmanthus fragrans、Cinamomum czmphora+Photinia serrulata Lindl、Castanea mollissima、Liquidambar formosana+Cinnamomum czmphora、Ginkgo biloba、Firmiana platanifolia+Osmanthus fragrans、Liquidambar fomosana+Firmiana platanifolia+Osmanthus、fragrans+Cinnamomum czmphora、Camptotheca acuminata,the one with strong comprehensive ability is Cynodon、Chimonanthus、Paulownia、Ophiopogon japonicus、etasequoia glyptostroboides、Celtis sinensis、Pseudolarix amabi1is、Liquidambar formosana +Firmiana platanifolia+、Liquidambar formosana +Celtis sinensis、Liquidambar formosana+Firmiana platanifolia,Liquidambar formosana+Celtis sinensis.(4)According to the analysis of litter decomposition and water holding effect,the allocation strategy of urban green space is put forward:according to the different needs of green space and according to the ability of plant litter,the allocation is staggered.