聚丙烯酰胺施用对碱土和非碱土水力传导度的影响

聚丙烯酰胺（PAM）可增加土壤结构的稳定性，但它对土壤水力传导能力的影响尚不清楚。通过室内土柱淋洗试验，研究了PAM施用量和施用方式对不同碱度土壤饱和水力传导度的影响。PAM施用量为0、1／5000、1／2000和1／1000（PAM与于土重之比），施用方式为混合施用和表面覆盖施用，土壤为碱土和非碱土两种。试验结果显示，在未施用PAM的条件下，非碱土水力传导度大于碱土。PAM混合施用显著地减小了土壤的稳定水力传导度，但它对碱土的影响程度大于对非碱土的影响。PAM覆盖施用降低了非碱土的稳定水力传导度；但碱土的稳定水力传导度随PAM施用量的增加先减小后增大。为了维持良好的土壤水力传导性能，应尽可能地减小PAM的施用量，或在非碱土地上采用混合施用而在碱土地上采用地表覆盖的施用方式。

EFFECTS OF POLYACRYLAMIDE APPLICATION ON HYDRAULIC CONDUCTIVITY OF SODIC AND NONSODIC SOILS

Polyacrylamide(PAM) can enhance soil structural stability,however its influence on soil hydraulic conductivity is not very clear.Effects of PAM application rate and method on saturated hydraulic conductivity were studied in laboratory through a soil column leaching experiment.PAM was mixed with the soils (sodic and nonsodic soils),respectiviely,or spread over surface of the soils at a rate of 0,1/5 000,1/2 000,and 1/1 000(PAM/dry soil in weight).The experimental results indicate that hydraulic conductivity of nonsodic soil was greater than that of sodic soil when no PAM was applied.PAM application through mixing obviously decreased steady hydraulic conductivity of the two soils,but its effect on sodic soil was greater than on nonsodic soil.PAM application through spreading decreased hydraulic conductivity of nonsodic soil.Steady hydraulic conductivity of sodic soil decreased with the increase in PAM application rate when the rate was low,but it increased when the rate was getting high.In order to maintain a great soil hydraulic conductivity,PAM application rate should be kept as lower as possible,or PAM is applied through mixing in nonsodic soil or through spreading on surface of sodic soil.