武汉市典型绿地植被类型对表层土壤入渗和持水性能的影响

Characterization of Surface Soil Water Infiltration and Retention Capacity in Urban Green Space of Wuhan City

合理的绿地植被建设和管理是提高城市蓄水能力和减少城市内涝的重要途径。该文以武汉市城区8种代表性绿地植被的表层土壤为研究对象,通过测定土壤理化性质和水力学特征参数,量化了不同类型绿地植被对表层土壤水分入渗和保持性能的影响,并揭示了土壤理化性质对其影响的机制。结果表明:不同植被类型表层土壤水分入渗性能和持水能力差异显著,天然香樟林、玉兰园、桂花园和牡丹园具有较好的入渗性能,表现为较高的饱和导水率(179.70~441.69 cm/d),其次是人工草坪(31.53~126.60 cm/d),而樱花园、梅花园和桃李园的入渗性能最差(22.40~57.99 cm/d)。天然香樟林土壤持水能力最强,表现为最高的田间持水量(0.315~0.336 cm^3/cm^3)和最大有效含水量(0.170~0.177 cm^3/cm^3),其次是玉兰园、桂花园、牡丹园、梅花园和桃李园,持水量、有效含水量分别为:0.241~0.289 cm^3/cm^3,0.144~0.182 cm^3/cm^3,而樱花园和草坪的持水能力最弱(0.209~0.254 cm^3/cm^3,0.139~0.165 cm^3/cm^3)。土壤饱和导水率与总孔隙度、非毛管孔隙度呈显著正相关关系,与容重呈显著负相关关系。而容重、总孔隙度、砂粒和粘粒含量是影响土壤水分特征的主要因素。可以通过乔灌木林下种植草本植物、减少人为践踏,以及适时翻耕等方式提高绿地土壤的入渗与保水能力,进而提高其降雨存蓄功能,减少城市内涝。

Reasonable green space vegetation construction and management is an effective way to increase urban water storage capacity and reduce urban waterlog.Eight urban green space locations characterized by different vegetation types in the Wuhan city were selected to collect the surface soil samples.The effects of green space vegetation types on water infiltration rate and water retention capacity of surface soils were quantified by measuring the soil physiochemical properties and hydraulic parameters.Furthermore,the relationships between the physiochemical properties and hydraulic parameters were analyzed.The results showed that significant differences of soil water infiltration rate and retention capacity were observed among the eight urban green space locations.The highest infiltration rate was observed in the natural camphor forest,magnolia garden,osmanthusfragrans garden,and peony garden(179.70-441.69 cm/d),characterized by the highest saturated hydraulic conductivity(Ks),followed by the artificial grassland(31.53-126.60 cm/d),and the lowest in sakura garden,plum garden,and peaches mixed plums garden(22.40-57.99 cm/d).The highest soil water retention capacity was observed in the natural camphor forest,characterized by the highest field water capacity(0.315-0.336 cm^3/cm^3)and the maximum effective water content(0.170-0.177 cm^3/cm^3),followed by themagnolia garden,osmanthusfragrans garden,peony garden,plum garden and peaches mixed plums garden(0.241-0.289 cm^3/cm^3,0.144-0.182 cm^3/cm^3),and the lowest in the sakura garden and artificial grassland(0.209-0.254 cm^3/cm^3,0.139-0.165 cm^3/cm^3).Significantly positive correlations were observed between Ks and soil total porosity/non-capillary porosity,and a significantly negative correlation between Ks and soil bulk density.The soil water retention capacity was mainly affected by the bulk density,total porosity,sand content,and clay content.The practices of planting herbaceous under the wood plants,reduce trampling,and addition soil tillage could be applied for the urban green space construction,which could improve the effects of rainfall conservation and reduce urban waterlog by enhancing the water infiltration rate and water retention capacity of surface soil.