Interpolyelectrolyte complexes as effective structure‐forming agents for Chernozem soil

Abstract

Chernozems or mollisols/black soils are 'reference soils' with a high content of organic matter, which ensures a high level of crop yield. In the article, we describe the structural characteristics of a typical medium‐thick Chernozem taken from Kursk region and their improvement via treatment by a 1 wt% aqueous solution/suspension of interpolyelectrolyte complex (IPEC), a product of electrostatic interaction between anionic potassium humates and cationic poly(diallyldimethylammonium chloride). The native Chernozem and polymer‐treated chernozem were characterized by laser diffraction, dry and wet sieving methods, transmission electron microscopy, soil washoff in a hydraulic erosion tray, gravimetry, visual control, and vegetation miniaturization in Petri dishes with the following main conclusions: (a) Deposition of a positively charged IPEC over the Chernozem sample led to an increase in a total amount of agronomically valuable 0.25–1 mm aggregates up to 28% in comparison with a 3% content of aggregates in the native Chernozem. (b) An average diameter of the air‐dry aggregates, treated by a cationic IPEC, was of 5.5 mm (cf. with 2.5 mm for the untreated). (c) An average diameter of the IPEC‐treated water‐resistant aggregates was of 2.1 mm (cf. with 0.5 for the untreated). (d) The Chernozem pretreated by the cationic IPEC showed a minimum removal of soil during several cycles of rewatering/drying. (e) All IPEC formulations, stimulated the growth of plants. The results are of interest for preparing low‐toxic polymer formulations capable of effective stabilizing fertile Chernozem soils.

Interpolyelectrolyte complexes based on hydrolyzed polyacrylonitrile for anti‐erosion stabilization of soils and ground

“…The mechanism of the stabilizing action of polymers is actively discussed in the literature 21 , 27 , 36–39 . On the surface of soil particles, there are regions (sites) with different affinities, which are involved in the binding of individual polymers and polycomplexes.…”

“…The mechanism of the stabilizing action of polymers is actively discussed in the literature. 21,27,[36][37][38][39] On the surface of soil particles, there are regions (sites) with different affinities, which are involved in the binding of individual polymers and polycomplexes. Cationic polymers are electrostatically adsorbed on the negatively charged sites; anionic polymers are bound to the cationic sites via polyvalent metal ion bridges.…”

“…Recently, the use of non‐stoichiometric IPECs (NIPECs) for soil stabilization has been described 24–27 . NIPECs can carry a total positive or negative charge depending on which PE, cationic or anionic, is in abundance 18,19 .…”

“…Recently, the use of non-stoichiometric IPECs (NIPECs) for soil stabilization has been described. [24][25][26][27] NIPECs can carry a total positive or negative charge depending on which PE, cationic or anionic, is in abundance. 18,19 Both 'cationic' NIPECs with an excess of a cationic polymer and 'anionic' NIPECs with an excess of an anionic polymer are soluble in water, so they can be applied evenly to the soil.…”

Sixth International Conference of the CIS IHSS on humic innovative technologies "Humic substances and ecoadaptive technologies" (HIT-2021)

“…Interpolyelectrolyte complexes (IPECs), the products of interaction between two oppositely charged polyelectrolytes (PEs), have been suggested for soil structure stabilization. An ability of IPECs to improve soil hydrophysical properties, prevent soil erosion and act as soil conditioners have been studied in our previous works [1]. The efficacy of IPECs was dependent both on chemical composition of IPEC and soil properties.…”