Synergistic Effects of Biochar and Farmyard Manure on Soil Health, Economic Returns, and Climate Change Mitigation in Cotton Production

Abstract

Soil health plays a pivotal role in ensuring sustainable agriculture, particularly in the face of climate change challenges. This field study evaluated the combined application of biochar and farmyard manure (FYM) on soil properties, cotton growth, yield, and economic return. The combined application of biochar and FYM (each at 2.5 t ha?¹) resulted in significant improvements compared to the control and sole amendments. Soil temperature was reduced (28.1 °C) relative to the control (29.5 °C), while soil pH remained unchanged. Total soil carbon and soil organic matter increased to 8.63%, 0.75%, respectively, under the combined treatment. Availability of essential nutrients like nitrogen (0.030%), phosphorus (9.10 mg kg?¹), potassium (115.30 mg kg?¹), copper (0.22 mg kg?¹), and zinc (0.70 mg kg?¹), was significantly enhanced compared with the control. Improved soil conditions resulted into superior crop performance, with higher plant height (176 cm), bolls per plant (48), and seed-cotton yield (3223 kg ha?¹). Moreover, the integrated biochar + FYM reduced irrigation requirement to eight irrigations, lowering total irrigation water use (6093 m³ ha?¹) and increasing crop water productivity to 0.52 kg m?³. Economic analysis revealed the highest net return (PKR 463,160 ha?¹) and benefit–cost ratio (3.39) under the biochar + FYM treatment. Overall, integrated application of biochar and FYM proved effective in enhancing soil health, water productivity, cotton yield, and profitability, highlighting its potential as a climate-smart and regenerative soil management strategy.