不同地表覆盖物对城市表层土壤物理性质的影响

Effects of different surface mulches on the physical properties of surface soil

研究不同地表覆盖物对土壤物理性质的影响,为减少城市绿地裸露面积、减少水土流失、建设海绵城市提供理论依据。共选择5种覆盖物(水性聚氨酯有机覆盖垫、酚醛树脂有机覆盖垫、园林绿化废弃物、树皮、鹅卵石)和对照进行桶装实验,研究其温度、水分、孔性等土壤物理性质的变化。结果表明:1)树皮覆盖可以在1月提升土壤温度,在7月降低土壤温度,园林绿化废弃物覆盖温差最小,水性聚氨酯有机覆盖垫7月日温差最小; 2)水性聚氨酯有机覆盖垫在春夏秋季土壤含水量显著高于其它处理,冬季差异不显著; 3)鹅卵石覆盖可显著增加土壤密度,其他处理之间密度差异不显著。综合指标表明水性聚氨酯有机覆盖垫和树皮覆盖对于土壤物理性质有较优的影响,可作为裸土覆盖的首选材料。

[ Background ] With the development of urbanization, human disturbance in the urban soil is more serious than the agricultural soil, thus it is easy to cause a series of adverse consequences such as soil physical property decline, soil erosion and haze weather. In order to improve this phenomenon, using mulch is an ideal way in urban surface soil management.[ Methods ] Five mulches with materials of waterborne polyurethane organic, phenolic resin organic, garden greening waste, bark, and pebble were selected and compared for a one-year barrel-packing experiment. Barrel-packing experiment referred to this: Soil was loaded into the bottom of the plastic barrel and covered with different mulches on the surface, which was repeated for 3 times to investigate the effects of different mulches on soil temperature, moisture, porosity and other physical properties. In this experiment, soil temperature, soil moisture and soil density were measured by curved soil thermometer. The data were processed by SigmaPlot Microsoft Office Excel 2007 and SPSS 21.0.[ Results ] 1) According to the influence of temperature of soil caused by different surface mulch in January and July, the soil temperature increased by garden greening waste and bark mulching in the 0-10 cm soil layer in January;the soil temperatures in the 10-20 cm soil layer under different mulching were lower than the control group, but the difference was small. In July, the soil temperature under the pebble mulch was too high, and the water-borne polyurethane organic mulch caused the soil temperature changing slowly. 2) Different mulches all increased soil moisture content. In the 0-10 cm soil layer, the soil moisture content under the waterborne polyurethane organic mulch pad was superior to other mulches, especially in spring, summer and autumn, which was significantly higher than that without mulching treatment. In the 10-20 cm soil layer, except that the soil moisture content under the coverage of garden greening waste was relatively poor in summer, the other treatments had better water retention effect compared with no coverage. 3) Pebble mulch significantly increased soil density in any soil layer, but there was no significant difference in soil density between other mulches except pebbles.[ Conclusions ] The comprehensive indexes showed that the organic mulch of waterborne polyurethane and the bark mulch had a better effect on the physical properties of soil. The bark mulch increased the soil temperature in January and decreased the soil temperature in July;meanwhile waterborne polyurethane organic mulch pad had minimum daily temperature difference in July. At the same time, both of them increased soil moisture content and caused no effect on soil density, thus they can be the first choice for mulching bare soil in the future.