Sustainable Nutrient Management and Agricultural Productivity in Chernozem Soils of the Kostanay Region, Kazakhstan

Abstract

Chernozem soils, known for their high organic matter and fertility, are crucial for agricultural productivity in northern Kazakhstan's Kostanay region. This study evaluated the physical, chemical, and biological properties of these soils to assess their suitability for crop production and propose sustainable management practices. Soil samples were collected from 0-20 cm depths across various locations to represent the region's main nutrient profile. Physical analyses included texture determination, while chemical analyses measured pH, electrical conductivity (EC), organic matter, and nutrient levels (N, P, K, Ca, Mg, Fe, Cu, Zn, and Mn) using standard methods. Biological assessments focused on microbial biomass carbon (Cmic), basal soil respiration (BSR), dehydrogenase and catalase activities, as well as Cmic: Corg and metabolic quotient (qCO₂) ratios. Results indicated high organic matter content (mean 4.49%), sufficient total nitrogen (>0.25%), and high levels of potassium and calcium. However, phosphorus levels were low (<8 mg kg⁻¹), marking it as a key limiting nutrient. Biological analysis revealed robust microbial activity, with high catalase activity supporting aerobic processes, but low Cmic: Corg and qCO₂ values suggested limited microbial biomass, potentially slowing organic matter decomposition. This trait, while preserving organic matter, may restrict nutrient mineralization, impacting crop nutrient availability. Based on these findings, we recommend prioritizing phosphorus and potassium fertilization integrated with organic matter management to balance nutrient levels and enhance crop productivity. The application of liquid or solid organic or organomineral fertilizers is suggested to maintain soil organic matter and promote sustainable practices. Additionally, foliar applications of manganese and iron, along with nitrogen supplementation, are recommended to address micronutrient deficiencies and support plant growth. Overall, sustainable management of Chernozem soils in Kostanay requires balanced nutrient management, organic matter preservation, and targeted micronutrient interventions to ensure long-term fertility and productivity. © 2025 Federation of Eurasian Soil Science Societies.