有机肥质量分数对土壤导水率稳定性的影响

Effects of the organic matter content on the stability of the soil hydraulic conductivity

饱和导水率是水循环和土壤侵蚀模型中的重要参数,也是土壤结构改善的重要指标。通过室内土柱模拟实验研究有机肥添加量对风沙土和塿土导水率的影响。土壤添加有机肥的比例设置为0%、5%、10%、15%、20%、25%、30%7个水平,土壤密度设3个水平,各处理5个重复。结果表明:1)土壤饱和导水率随有机肥质量分数的增加呈降低趋势,风沙土的饱和导水率随有机肥质量分数的增加呈直线下降趋势,而塿土饱和导水率的降低趋势随有机肥质量分数的增加减缓;2)有机肥质量分数的增加对土壤密度的降低作用可以抵消有机肥增加导致的饱和导水率的降低;3)低土壤密度下土壤导水率随时间变化不稳定,土壤密度增大后随时间变化稳定。随着有机肥质量分数的增加,土壤导水率的测定过程趋于稳定,但是测定时间延长。

Soil saturated hydraulic conductivity （Ks） is an important hydraulic parameter of water cycle and soil erosion model,and it is also an important indicator of the improvement of soil structure.The objective of our study is to investigate the effects of organic fertilizers on Ks for sandy soil and Lou soil.The content of organic fertilizers in the soil was set as 0％,5％,10％,15％,20％,25％ and 30％.Three levels were designed for soil density （depending on trial of packing）.Each treatment had five replicates.Soil columns with constant head of water were used to determine Ks.The results showed that 1） Ks decreased with the increase of organic fertilizer content.The effects of organic fertilizer content on Ks of sandy soil and Lou soil were different.Ks of sandy soil declined linearly with the increase of organic fertilizer content,while Ks of Lou soil decreased slowly as the organic fertilizer content increased.2） Soil density would decrease when adding organic fertilizers to soil,but Ks would not significantly decline with the increase of organic fertilizer content for both soils under the lower soil density condition.3） Due to the addition of organic fertilizers,the procedure of K determination was stable,but the time spent for determination became longer.Under the lower soil density condition,the change of K over time was not stable.When soil density increased,the change of K over time would become stable for all levels of organic fertilizer content.