Interpolyelectrolyte complexes as effective structure‐forming agents for Chernozem soil

Abstract

AbstractChernozems 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.