| Bare soil in urban green space increases year by year in China.The existence of bare soil not only generates a large number of soil dust,but also makes the soil quality become worse.And a large number of garden waste is produced every year,it is very difficult to deal with it.In this study,the garden waste(dry branch)was made into mulching mats,and then the basic properties and other water holding properties of mulching mats were studied and used to choosing the best proportion of adhesive Mulching mats and some other mulching materials which are widely used in cities were covered on bare soil to investigate their effects on soil physical-chemistry properties,weed inhibition and soil dust reduction.So it could provide a theoretical basis for the recycling of garden waste and scientific management of urban green space.Specific results showed that(1)The bare soil area of the urban green space within the 4th Ring of Beijing was large,the bare soil area in the non-growing season accounted for 36.70%,20.70%and 88.87%of the lawn land,shrub land and tree pits respectively,and the bare soil area accounted for 9.11%,5.61%and 77.21%in the growing season respectively.The total area of bare soil in non-growing season was 10551.82 m2,accounting for 8.98%of the total area.The total area of bare soil in the growing season was 2840.25 m2,accounting for 1.91%of the total area.The soil quality under different inorganic mulching materials in urban green space of Beijing gradually decreased with the depth increasing.Water permeable brick,cobblestone and tree pit nets had no strong effects on soil physical-chemistry properties,even sometimes some of those could make soil physical-chemistry properties become worse(2)The ecotoxicity test showed that waterborne polyurethane(WP)and urea formaldehyde resin could be chosen as the adhesive to manufacture mulching mats that made of garden waste.Analysis on the basic properties,water retention effect,water permeability and water holding capacity of mulching mats,30%adhesive proportion was the best to manufacture mulching mats(WP)which made by small particle size's garden waste,and 35%was the best for another.For the mulching mats that made by urea formaldehyde resin,30%and 35%adhesive proportion for the garden waste of small particle size and the large particle size were selected respectively.The mulching mats made by small particle size's and large particle size's garden waste were more suitable to cover bare soil in arid regions and humid regions respectively.(3)The compression performance of mulching mats that made of garden waste were far more than the maximum pressure of pedestrians,which was enough to prevent the pedestrians from stepping on.The mulching mats could not be ignited by cigarettes,and it would not bring the hidden danger to the urban green space in the process of use.With the increasing of urea formaldehyde resin size,the release of formaldehyde from the mulching mats was also increasing,but it was still lower than that from the natural state of forests,so it could be used to cover bare soil.(4)The mulching mats made by two kinds of adhesives had significant effect on improving soil moisture and soil temperature changes,and were better than wood chip mulching and cobblestone mulching.They also had significant effect on improving soil organic matter and available nutrients,and were similar to wood chip mulching effect.The soil pH could be reduced by covering the mulching mats that made by waterborne polyurethane,the mulching mats that made by urea formaldehyde resin and wood chips had no significant effect on improving the soil pH.The mulching mats made by two kinds of adhesives could greatly reduce the aboveground biomass of weeds and significantly reduce the coverage of weeds,and also had higher weed inhibition rates.Their inhibition effect was better than wood chips and cobblestones.For covering bare soil and thereby reducing dust pollution,mulching mats had the best effect and were better than garden waste,pine barks and cobblestones. |
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