广州南沙区4种典型城市林业土壤质量调查研究

Soil nutrient analysis and fertility of urban forestry in Nansha District,Guangzhou

为掌握广州南沙区城市林业土壤养分及肥力整体状况,提高广州南沙区城市林业土壤管养水平,以广州南沙区4种典型城市林业土壤(森林公园、湿地公园、生态景观林带、河涌防护林)为研究对象,测定土壤pH值、电导率、容重、渗透率、非毛管孔隙度、有机质、水解氮、有效磷、速效钾等9项理化指标,通过土壤理化性质分析、土壤综合肥力分析,对广州南沙区城市林业土壤养分及肥力进行评价。结果表明,森林公园pH为6.4、湿地公园pH为6.8、生态景观林带pH为7.1、河涌防护林pH为7.3,广州南沙区林业土壤pH在中性(pH 7.0)上下波动。土壤EC值除森林公园较低外,其余生境类型处于正常范围,土壤有机质含量为14.81—33.02 g·kg^(-1)整体水平较好,其中一半区域土壤水解氮含量为41.97—58.95 mg·kg^(-1)、土壤速效钾含量为48.29—52.61 mg·kg^(-1)处于中下水平,土壤有效磷含量为5.8—36.75mg·kg^(-1)整体水平较充足。南沙区林业土壤整体综合肥力较贫瘠,其中森林公园、湿地公园、生态景观林带土壤综合肥力指数(0.90—0.99)略高于贫瘠标准(<0.9%),只有河涌防护林土壤综合肥力指数为1.18达到一般标准(0.9%—1.8%)。土壤有机质含量对土壤水解氮含量影响较大,土壤有机质含量对土壤有效磷含量影响小于对土壤速效钾含量的影响。土壤整体容重偏低,从总体看,容重及土壤速效养分是南沙区城市林业土壤综合肥力的突出性限制因子,说明容重和土壤速效养分与南沙区土壤综合肥力关系紧密。该研究可为广州南沙区城市林业土壤养护、修复提供依据。

In order to explore the overall status of urban forest soil nutrient and fertility and to improve the soil management level of urban forestry in Nansha District of Guangzhou,4 typical urban forest soils(forest park,wetland park,ecological landscape forest belt,river shelter forest in Nansha district of guangzhou)were studied in this paper.Soil pH,conductivity,bulk density,permeability,non capillary porosity,organic matter,hydrolyzed nitrogen,available phosphorus,available potassium,the 9 physical and chemical indexes were measured.Through the analysis of physical and chemical properties of soil and soil comprehensive fertility,the soil nutrients and fertility of urban forestry in Nansha area were evaluated.The experiment results show that the pH value of forest park was 6.4,that of wetland park was 6.8,that of ecological landscape forest belt was 7.1,that of river shelter shelter forest was 7.3,and that of forestry soil in Nansha District of Guangzhou fluctuated in a neutral pH value(pH 7.0).The soil EC value was in the normal range except for the forest park,soil organic matter is 14.81-33.02 g·kg^(-1),hydrolyzed nitrogen in half of the soil was 41.97-58.95 mg·kg^(-1),available potassium in the soil was 48.29-52.61 mg·kg^(-1),and the available phosphorus content overall level is sufficient was 5.8-36.75 mg·kg^(-1).The comprehensive fertility of urban forestry soil in Nansha District of Guangzhou is relatively poor,forest park,wetland park,ecological landscape forest soil comprehensive fertility(0.90-0.99)slightly higher than the barren standard(<0.9%),only the soil comprehensive fertility of river shelter forest reached the general standard(0.9%-1.8%).Soil organic matter content has great influence on soil hydrolyzed nitrogen content.Soil organic matter content has less effect on soil available P content than on soil available K content.The overall bulk density of soil is low.On the whole,bulk density and soil available nutrients are prominent limiting factors for the comprehensive fertility of urban forest soil in Nansha area.The results show that bulk density and soil available nutrients are closely related to soil comprehensive fertility in Nansha area.This study can provide a basis for the conservation and restoration of urban forestry soil in Nansha District,Guangzhou.