贵州主要耕作土壤的脲酶活性研究

首次较系统、全面地测定了贵州省主要耕作土壤的脲酶活性，分别探讨了水稻土和旱作土脲酶活性与土壤主要理化性状之间的关系。结果表明：耕作土壤脲酶活性因土壤利用状况、土壤类型和土壤肥力水平不同而有明显的差异，供试水稻土、旱作土和菜园土的平均脲酶活性分别为１５５、２７７和７０３ｍｇＮＨ４－Ｎ／１００ｇ土·２４ｈ；不同类型水稻土和旱作土具有不同的脲酶活性水平，这主要受成土条件、成土过程和土壤属性的影响；水稻土和旱作土的脲酶活性均随土壤肥力水平的提高而增强，说明脲酶活性强弱是表征土壤肥力高低的重要指标之一。回归分析表明，土壤脲酶活性主要受土壤有机质、氮、磷、钾等因素的影响，其中土壤基础铵量对耕作土壤脲酶活性的影响最大。水稻土脲酶活性还受土壤通透性的制约．而旱作土的则主要受土壤养分状况的影响。

Study on Urease Activity of Main Cultivated Soil in Guizhou

Urease activity of main cultivated soil in Guizhou was determinated systematically and extensively. The relationship between urease activity of paddy soils andupland-cultivated soils and main soil physico-chemical properties was studied. The results showed that urease activity of cultivated soils were very different in soil utilizationregime, soil types and properties. The average urease activity of paddy soils, uplandcultivated soils and vegetable garden soils were 155, 277 and 703 mg NH4-N/100g soil.24h, respectively. There were great differences in urease activity among different typesof paddy soils and upland-cultivated soils. This result was affected mainly by soil forming condition, soil-forming process and soil properties. Urease activity levels of paddysoil and upland-cultivated soil increased with the increase of soil fertility level. It wasone of the main indexes of cultivated soil fertility level. The regression analysis resultsshowed that urease activity was affected mainly by regimes of nitrogen and phosphorus,content of organic matter and available potassium, etc. But basic ammonium quantityinfluenced urease activity more pre-eminently than other soil properties.