广州城市公园绿地土壤肥力及酶活性特征

采集广州市中心城区部分公园绿地表层土壤（0-20 cm）,研究了土壤pH、有机质、粘粒、氮、磷、钾含量等肥力特性和脲酶、蔗糖酶、磷酸酶活性。结果表明,广州公园绿地土壤以酸性（pH 4.5-5.5）和中性（pH 6.5-7.5）占的比例高,部分土壤呈碱性,土壤pH值较自然土壤有增高的趋势;土壤有机质含量以中等水平为主,土壤全氮、碱解氮以中等到低水平为主。土壤全磷和有效磷以中等以上水平为主,土壤全钾、速效钾以中等以上水平为主,土壤脲酶、蔗糖酶和磷酸酶活性平均分别为0.36 m g NH3-N/g,12.29 m g葡萄糖/g和2.14 m g酚/g。不同公园绿地土壤肥力特性和土壤酶活性呈现出一定的差异性。土壤脲酶、蔗糖酶和磷酸酶活性之间相关性均达到极显著水平（p〈0.01）;土壤蔗糖酶、脲酶和磷酸酶活性与土壤有机质等肥力性状之间呈显著或极显著的相关性,可以作为评价广州公园绿地土壤肥力的指标。

Soil Fertility Characteristics and Enzyme Activity for Urban Parks in Guangzhou City

Surface soil samples(0~20 cm) of several urban parks were collected at central district in Guangzhou city,and soil pH,organic matter,clay,N,P,K content,urease,sucrase and phophatase activities were studied.The results indicated that the soil pH value was dominated by acid(pH4.5~5.5) and neutrality(pH6.5~7.5),and had increase tendency as compared with natural soils;soil organic matter was dominated by medium level;soil total N and alkali-hydrolyzable N were medium to low level;soil total P,available P,total K and available K were medium or over medium level.The average values of soil urease,sucrase and phophatase activities were 0.36 mg NH_3-N/g,12.29 mg glucose/g and 2.14 mg phenol/g respectively.The soil fertility properties and enzyme activities had significant difference among urban parks.There existed marked correlation among soil urease,sucrase and phophatase activities(p<0.01).Soil urease,sucrase,phophatase activities and soil fertility properties such as soil organic matter etc.had significant correlation,and their activities can be taken as one of index for assessing soil fertility of Guangzhou urban parks.