Reclamation Efficiency of an Organomineral Compost-Ameliorant for Cotton Cultivation on Degraded Irrigated Soils in Southern Kazakhstan

The aim of this study is to evaluate the reclamation efficiency of an organomineral compost-ameliorant for the restoration of degraded irrigated soils and its effects on cotton productivity under the conditions of southern Kazakhstan. Based on field studies, the effects of applying the compost-ameliorant at rates of 5 and 10 t/ha on soil cation composition, the availability of plant nutrients, and cotton yield were assessed. The application of the compost-ameliorant improved the composition of the soil cation exchange complex: the proportion of exchangeable calcium increased from 64.5% in the control to 69.9% and 71.7%, while exchangeable sodium decreased from 0.5% to 0.4% and 0.2% at application rates of 5 and 10 t/ha, respectively. At the same time, the availability of nitrogen and potassium in the soil increased. The mean seed-cotton yield increased from 3.06 t/ha in the control to 4.36 t/ha with the application of 5 t/ha and 4.44 t/ha with 10 t/ha, with the highest yield obtained at the 10 t/ha rate, providing an increase of 1.38 t/ha.