The effect of humic acid in composition with polyacrylamide copolymers on wind and water soil erosion

Abstract

Abstract The present study, for the first time, the optical, electrokinetic, and mechanical properties of humic acid (HA) extracted from brown coal of the Shubarkul deposit (Kazakhstan) were investigated in combination with anionic and cationic polyacrylamide copolymers. These polymers were employed as novel, environmentally friendly, and sustainably available binders (stabilizers) aimed at mitigating soil erosion caused by wind and irrigation, while also enhancing soil structural stability. This pioneering research explores the potential of regionally sourced HA in the development of HA– copolymer polyacrylamide systems for soil protection applications. The lowest mechanical strength (Pm = 22.5 kg/cm²) was observed in the sample treated with humic acid (HA). The highest value was demonstrated by the anionic copolymer polyacrylamide, which facilitates the formation of various chemical elements and physical bonds with soil particles. The compositions of HA with P(AAm-co-AA) and P(AAm-co-DADMAC) at HA concentrations of 0.01 wt% and 0.03 wt% increased the plastic strength by 1.5 and 2 times compared to using only P(AAm-co-AA). Experimental results demonstrate effective suppression of simulated wind and water erosion in soils treated with 0.4 wt% P(AAm-co-AA) and humic acid at concentrations of 0.02 wt% and 0.05 wt%. In addition, the application of these natural binders for promoting plant growth was investigated as a novel approach. The studied compositions showed a positive effect on radish growth a plant highly sensitive to aggressive environments and toxic compounds thereby confirming the environmental compatibility and potential applicability of the materials in the agricultural industry.