Dynamic Effect of the Dissolution Time of PAM on Soil Saturated Hydraulic Conductivity
Two soils (clay loam and sandy loam) and three addition levels of PAM (0, 22.5, 45 kg/hm2) were used to measure the dynamic changes of soil saturated hydraulic conductivity(KS) under constant water flow (10.25 mm/h), the content and stability of soil aggregates and thus to investigate the mechanisms for the effect of the dissolution time of PAM on KS. Results showed thatKS decreased as the dissolving time of PAM increased, and finally researched a stable state. When the dissolving time of PAM was shorter, theKS of the PAM treatment was higher than that of control. The sandy loam soil with PAM of 45 kg/hm2 had the highest grow rate ofKS, and theKS was increased by 26.87% compared with control. TheKs did not change with the amount of PAM added. PAM stabilized the aggregate structure of the soils, increased the amount of water-stable aggregate, and thus improved theKS. The amount of the water-stable aggregate of > 0.25mm for the treatment with 45 kg/hm2 of PAM added was 8.91% more than the control in sandy loam soil, while that for clay loam soil increased by 32.54%. When the dissolving time of PAM was long enough, theKS of PAM treatment was significant lower than control, and the largest reduction was observed in the treatment with 45 kg/hm2 of PAM in clay loam soil, and theKS was decreased by 10.86% compared with control. However, theKs did not change with the amount of PAM added significantly. For the related mechanisms, PAM increased contents and stability of soil aggregates and thus improvedKS. On the other hand, after PAM dissolving in water, the solution became glutinous. PAM also adsorbed soil particles and blocked soil pore and thus decreased theKS. We found that PAM improved the structure of sandy loam soil better than that of clay loam soil. The study will provide a theoretical basis for improving soil transparent performance with PAM.
国家科技期刊平台
NSTL
万方数据
维普
