绿肥种植对石灰土脲酶活性与土壤肥力的影响

目的]探讨绿肥对石灰土的增肥效应。方法]取桂林毛村常年种植过紫云英绿肥的冬闲田和自然抛荒农田中的石灰土,测定石灰土的脲酶活性和土壤肥力。结果]绿肥种植大大提高了石灰土N、P、K的有效态、全氮含量及脲酶活性,但对全磷、全钾的增加不明显。石灰土脲酶活性与石灰土氮磷钾全量、碱解氮、速效钾呈显著相关。石灰土脲酶活性呈垂直分布规律,从耕作层到犁底层下降明显,从犁底层到底土层下降缓慢。石灰土肥力在垂直方向上呈明显的递减规律。石灰土速效钾对脲酶活性的直接作用有较强的负效应,但其间接作用使其与脲酶活性在表观上显示正相关关系。结论]脲酶活性是表征石灰土肥力水平的重要指标。

Effect of Planting Green Manure on Urease Activity and Soil Fertility of Lime Soil

Objective] The study was to explore the improvement effect to soil fertility of planting green manure on soil fertility in lime soil.Method] The lime soil from the winter fallow field in which Chinese vetch green manure was once planted and the natural barren field in Guilin Village were taken to determine urease activity and soil fertility of the lime soil.Result] Planting green manure greatly increased the available state of N,P,K,total N contentand urease activity in lime soil,but it had no obvious increase on the content of total P and total K.The urease activity of lime soil had significant correlation with total content of N,P,K and alkaline hydrolytic N and available K in lime soil.The urease activity of lime soil showed a vertical distribution law,and it was obviously decreased from plough layer to plowpan,while it was slowly decreased from plowpan to bottom layer.The soil fertility of lime soil showed a obvious decline law in vertical direction.The direct effect of available K on urease activity of lime soil was a strong negative effect,but its indirect effect made it show positive correlation with urease activity in appearance.Conclusion] Urease activity was a important index which reflected the fertility level of lime soil.