Influence of diatomite on physicochemical characteristics of saline chestnut solonetz soils of Northern Kazakhstan

Abstract

Background and Aim. Soil salinization is a major limiting factor for agriculture, causing changes in soil microbiota composition, and exacerbating land desertification and biodiversity loss, especially under climate change. This experiment aimed to study the physicochemical properties of diatomite as an additive (ameliorant) in initially saline soils to improve their chemical properties and fertility.

Materials and Methods. The objects of the study were samples of loamy solonetzic chestnut soils (upper horizons 0-20 cm and 20-30 cm) from the Nura district, Karaganda region, and diatomite from the Zhalpak deposit, West Kazakhstan region, used as an ameliorant. The main research meth-ods included physico-chemical, chemical and biological analyses. The studies were carried out in threefold replication.

Results. The experiment revealed a positive effect of natural diatomite additives on the properties of solonetz soils. Due to the adsorptive properties of diatomite, there was a sorption of easily soluble salts throughout the studied depth, particularly toxic chlorine ions. A decrease in Na⁺ in the soil absorption complex (SAC) was observed, resulting in the improvement of the structure of the initially dense soil. The experiment showed maximum improvement in the structure of initially very dense and hard soil when the maximum dose of diatomite 12% was applied. Thus, we suggest that improvement of soil structure under the influence of diatomite is associated with changes in the composition of exchangeable cations in the SAC.

Conclusion. The observed reduction in easily soluble salts (ESS) and the improvement of soil structure in the presence of diatomite suggest that this mineral can be used to bring saline lands back into crop rotation. The reduction of Na⁺ in the ESS indicates that diatomite can effectively improve the fertile properties of solonetz.