Effects of applications of synthetic polymer and humic acid on resistance to dispersion and mechanical forces

In this study, the effects of the addition of polyvinyl alcohol (PVA), polyacrylamide (PAM), and humic acid (HA) to soils in sandy loam, loam, and clay texture classes on their resistance to dispersion and mechanical forces were examined. The study was performed under greenhouse conditions using surface soil samples and 1.5 kg pots. Furthermore, the study was planned as an incubation experiment and the application of PVA, PAM, and HA at 500, 100, and 500 ppm doses for each soil texture class, respectively. During the incubation times (1 (0), 2 (15), 3 (30) 30, and 4 (45) days), the irrigation process was repeated as half of the available moisture in the soil was depleted. Ultimately, the applications of PVA, PAM, and HA on soils in sandy loam, loam, and clay textures increased the liquid limit/ pF'2 moisture ratio (LL/pF'2) values in them by 6.30%, 5.99%, and 7.30%, respectively, (reducing the tendency to dispersion) compared to the control. Furthermore, the applications increased the plastic limit/pF’2 moisture ratio (PL/pF’2) values (resistance to mechanical forces) by 22.31%, 16.50%, and 9.27%, respectively. Incubation time 1 was more effective in reducing dispersion and increasing resistance to mechanical forces, and the effects decreased over time. PVA was the most effective conditioner for all three soil groups.