钾肥类型与施用量对土壤持水特性的影响

采用压力膜法测定了单施磷酸二氢钾、单施草木灰和两者配施等3种钾肥类型在不同压力下的土壤质量含水率,拟合了它们在不同氧化钾含量的土壤持水曲线。结果表明,3种钾肥类型均降低了土壤的持水性,单施草木灰对土壤的持水力降低幅度最大,但采用两者配施对土壤持水力无显著影响,且施用量的多寡对土壤质量含水量的影响不显著。分析认为,钾肥类型应以草木灰与无机肥配施为好,施用量采用中肥水平即有效钾含量在100mg/kg左右,不仅避免连续大量施用无机肥对土壤结构的破坏,而且减小施用草木灰对土壤持水力的影响。

Effect of potassium fertilizer application on soil water retention capacity

The mass soil water content was measured using pressure membrane method under three forms of potassium fertilizer,potassium dihydrogen phosphate,plant ash and mixed application of them with potassium oxide content of 50mg/kg,100mg/kg and 200mg/kg,respectively,and fitting the soil water retention curve.The results showed that plant ash significantly reduced soil water retention capacity,mixed application of potassium dihydrogen phosphate and plant ash had no significantly effect on soil water content.Combined application of chemical potassium fertilizer and plant ash not only can relieve contradiction between potassium fertilizer supply and requirement,but can regulate soil capacity of preserving water and fertilizer.