Phosphorus deficiency and declining organic matter limit crop productivity in Northern Kazakhstan’s chernozem soils. This study evaluates whether the combined application of phosphorus fertilizer and an ash-carbon amendment from industrial by-products can improve soil fertility and barley yield. In a three-year field experiment (2018–2020), four P rates (1/10, 1/5, 1/2, and the full recommended dose, Prec) were tested with 100 kg ha⁻¹ of ash–carbon product (“Agrobionov”). Across growth stages, we measured cellulolytic microbial activity, water-stable soil aggregates (%WSA), and grain yield. Relative to the control, P + ash–carbon increased microbial activity by up to 57.6% and %WSA by up to 76%. The highest yield (1.32 t ha⁻¹) occurred with Agrobionov + ½ Prec, a 51.7% increase over the control. These results indicate that pairing moderate P rates with an ash–carbon amendment enhances soil biological and physical properties and improves yield in P-deficient chernozems, supporting the sustainable use of industrial by-products as cost-effective soil amendments. Future work should assess long-term effects on C sequestration, nutrient cycling, and economic feasibility.

Degradation, reduction of soil fertility, and accumulation of industrial waste is both global and national environmental problem. The purpose of the study is to evaluate the effectiveness and environmental safety of the use of fertilizers made from ash and slag on ordinary chernozem for common flax (Linum usitatissimum) crops. The laboratory experiments were conducted in the environmental protection laboratory. The field experiments were conducted at the experimental field of Kokshetau University named after Sh. Ualikhanov in the period from 2018-2020. The content of heavy metals was determined by inversion voltammetry. It was found that the fertilizer made from ash and slag contributed to the improvement of edaphic factors. On average, over 3 years, the content of agronomically valuable aggregates increased to 65.9-73.2% (56.7% in the control variant) and the water resistance of soil aggregates increased by 7-29% compared to the control variant. The ecotoxicological assessment showed that the application of fertilizers in doses of 100-500 kg/ha on ordinary chernozem did not significantly affect the content of heavy metals in the soil compared to the control variant and also did not exceed the maximum permissible and approximately permissible concentrations. On fertilized variants, the increase in the yield of common flax grain averaged 0.09-0.34 t/ha, depending on the dose of application. The greatest increase in yield was obtained in the variant "background +300 kg/ha of fertilizer", which was 51.5% higher than in the control variant. In fertilized variants, a net income of $341.2 was received, which exceeded the control variant by $125/ha; thus the profitability was 257%. Studies have shown that the introduction of fertilizer from ash and slag into the soil in doses of 100-500 kg/ha is environmentally safe.

Modern agriculture in Kazakhstan is carried out by an extensive method and accompanied by a noticeable decrease in soil fertility, in particular the biological and agrochemical properties as the main reason of insufficient fertilizer applications. The objectives of the research were to study the Agrobionov doses effect applied during soil preparation on microflora species composition, microbiological activity, availability of plant nutrients in soil, and barley grain yield. The preparation substances are produced from industrial wastes - coal ash, slag and carbon black. The experiments were carried out in the Northern Kazakhstan on the experimental field of Ualikhanov Kokshetau State University. The soil is represented by ordinary chernozem, carbonate, medium-power, lowhumus, heavy-loam. The cellulose-decomposing activity of soil bacteria was determined by the application of flax cloth. Microflora was studied on solid nutrient media, the productivity of barley grain by the continuous method. It has been established that preparation substances promote an increase in the total number of microorganisms, including nitrogen consuming microorganisms, oligonitrophils, phosphorus mobilizing, cellulose-decomposing, fungi, nitrogen nutrition improvement of soil, the increase of grain yield. The preparation substances improve biological properties, nutritional regime of soil, raises barley productivity, and also has ecological significance in terms of production waste utilization.

The article presents the results of a study on the growth, development, response to mineral nutrition and yield stability of 16 varieties of spring barley on chernozem soils of Northern Kazakhstan, cultivated under three backgrounds of mineral nutrition—without fertilizers, half of the calculated dose (N₃₀P₃₅) and the full calculated dose (N₆₀P₇₀) of fertilizers. The reserves of productive moisture, the content of nitrate nitrogen, mobile phosphorus, exchangeable potassium, pH of the water extract in the soil, phenological development of plants, plant density, elements of crop structure, yield, ecological plasticity to mineral nutrition and stability of yield of barley varieties were studied. It was found that the use of mineral fertilizers increased the average grain yield by 0.29–0.46 t/ha (24.0–38.0%) compared to the unfertilized background. The varieties Kudesnik (+0.77 t/ha; +98.7%), Prairie (+0.80 t/ha; +63.0%) and Arna (+0.64 t/ha; +66.0%) showed the greatest response to fertilizers; the maximum yield was achieved by the varieties KWS Salome (2.30 t/ha) and Vakula (2.28 t/ha) with the full calculated dose of fertilizers. Correlation analysis showed that, against an unfertilized background, yield was most closely related to the 1000-grain weight (r = 0.75), the number of plants before harvesting (r = 0.63), and the number of productive stems (r = 0.53), indicating the leading role of these traits in yield formation. The values of the ecological plasticity coefficient (bi) varied from 0.6 to 1.7, and the yield stability index (Hom) varied from 3.4 to 6.9, which reflects significant differences in the adaptive response of varieties to changes in the level of mineral nutrition. According to the type of adaptability, the following varieties were selected for extensive technology: Velikan, Slavny, Divny, Abalak, Kerzhak, for resource-saving: Astana 2000, Arna, Tselinny-60, Grace, Eifel and intensive technology: KWS Salome, Vakula, Prairie, Paustiana, Ara, Kudesnik, recommended for the corresponding cultivation technologies.