Effect of Polyvinyl Acetate Polymer on Stability of Dry Aggregates

Wind and water erosion are among the main causes of damage to the soil and environment. In previous studies, a great emphasis has been placed on the role of aggregates stability in erosion control and prevention of particles movement and displacement. For this purpose, the use of polymeric materials to control wind erosion has been considered, but the amount and duration of their effects on aggregate stability in different soils must be determined. This study aimed to investigate the impact of a Polyvinyl Acetate-based polymeric emulsion on dry aggregate stability, time-variation of dry Mean Weight Diameter (MWD), and optimum amount of polymer in different soils. To do this, three different soils were selected with light, medium, and heavy texture and soil characteristics such as determination of initial water content, particle size analysis, hydrometer tests and Atterberg Limits were determined. Later, 12 treatments were applied using four levels of 0, 25, 40, and 50 g/m2 of polymeric material with concentrations of 0, 25, 40 and 25 gr/lit and with three different soils. Then, in one day, one month, three, and six months intervals after preparation, the MWD of treatments were measured in three replications. Statistical analysis showed that, in many time intervals, application of polymeric material had significantly increased the MWD compared to water treated (control) samples, and both the amount of polymeric material and the volume of added emulsion affected aggregate stability. Compared to the water treated samples, the effect of all polymeric treatments on dry aggregate stability of sandy soil were considerable even after 6 months. MWD values of all polymeric treatments of the silty loam soil were higher than the control samples till 3 months but, after six months, only the MWD of polymeric treatment of 50 gr/m2 was still greater than the control. Also, in polymeric silty caly loam soil, only the MWD of the 50 gr/m2 treatment was still greater than the control samples after six months. Finally, polymeric treatment with 25 gr/m2 application was chosen as effective treatment because of having the lowest applied polymeric material and lowest polymeric emulsion volume.