تاثير پلي اكريل آميد بر فرسايش و رواناب خاك هاي شور- سديمي

The Effect of Polyacrylamide on Erosion and Runoff in Saline-Sodic Soils

This study was conducted for evalulating the effect of Polyacrylamide (PAM) application on runoff and erosion control. Four soils of the same texture (clayey) and different saline-sodic properties were selected. Soil samples were placed in 25x25 cm trays and saturated twice through capilarity rise. After the second saturation stage, when soil moisture reached about 12% by weight, Polyacrylamide (PAM) solution was added to the soil surfaces at rates equivalent to 10, 20 and 30 Kgha^-1. The trays were placed on a rain simulator frame of 20% slope and then rain intensity of 30 mmh^-1 was applied to soil sample surfaces for a duration of 5 minutes, using the rainfall simulator. This procedure was repeated with a rainfall of 40 mmh^-1 intensity. It was observed that all the PAM treated samples were significantly different from control, regarding runoff and soil loss. Soil loss in solis (SAR= 87 (meql^-1)05 and (EC = 18 dSm-l) with 0 kg/ha of PAM application as well as in soils (30< SAR< 95 (meql^-1)05 and EC=10-13 dSm^-1) with 30 Kg/ha of PAM application (both subjected to 30 mm/hr rain intensity) was observed to be the least. Loss in all soils with 30 Kg/ha of PAM application (subjected to 40 mm/hr rain intensity) was also observed to be the least. As far as runoff is concerned it was observed to be minimum for soils subjected to 30 mmh^-1 and 40 mmh^-1when treated with 20 and 30 Kgha^-1 of PAM respectively.