Synergistic Structuring and Stabilization of Arid Agro-Soils via a Binary Metacid–Chitosan Interpolymer Complex

This study investigates the effectiveness of using an interpolymer complex based on a synthetic polycation—Metacid (polyhexamethylene guanidine hydrochloride) and a natural biopolymer—chitosan for anti-erosion soil structuring in the Maktaaral district of the Turkestan region. Using the conical plastometry method, the critical concentration of structure formation in the soil suspension was determined to be 67.5%; for subsequent studies, the solid phase content was taken to be 70%. Rheological studies have revealed a pronounced synergistic effect of the combined use of Metacid and chitosan. If the initial soil–water system is characterized by low elastic moduli (E1, E2 ~ 104 Pa), then the introduction of the “Metacid–chitosan” interpolymer complex leads to a sharp strengthening of the structure: The values of E1 and E2 increase to 3.26·106–7.49·106 Pa and 1.04·106–1.46·106 Pa, respectively. The mechanical stability limit increases by more than twofold, reaching 2000–2500 Pa. Analysis of the ζ-potential and electrical conductivity showed that the Metacid ensures a high positive charge of the complex (+21.76 … 28.69 mV), and chitosan acts as a spatial matrix. Experiments in a wind tunnel have confirmed that the “Metacid–chitosan” formulation, at an optimal concentration of 0.4%, provides effective protection of soil aggregates against wind erosion. The results obtained open up new prospects for using ecologically balanced interpolymer complexes to stabilize arable lands.