Synergistic Effects of Integrated Organic and Mineral Fertilization on Soil Nutrient Dynamics and Cotton Productivity in Irrigated Meadow-Alluvial Soils of Arid Uzbekistan

A field experiment was conducted in 2019–2021 in the Shavat district of the Khorezm region, Uzbekistan, to determine how mineral fertilizers combined with farmyard manure affect nutrient availability and cotton productivity in old-irrigated meadow-alluvial soils. Five fertilizer treatments were tested under furrow irrigation in a randomized complete block design with three replications. Soil nutrient status, nutrient accumulation in cotton organs, growth parameters, and seed cotton yield were evaluated. The treatment N200P150K100 + 25 t ha-1 manure gave the strongest agronomic response. In this treatment, the 0–30 cm soil layer contained higher nitrate nitrogen, available phosphorus, and exchangeable potassium during the main growth stages, and cotton plants accumulated more N, P, and K in leaves, stems, and bolls. The highest mean yield was 34.8 c ha-1, which exceeded the unfertilized control by 86.1%. A further increase in mineral fertilizer rate did not improve yield. Under the studied conditions, the balanced mineral–organic regime was more effective than the highest mineral fertilizer input.