Valorization of Farmyard Manure Compost as a Sustainable Amendment for Rehabilitating Degraded Non-Cracking Soils

Degraded non-cracking soils (locally known as Naga’a) are widespread in semi-arid regions of Sudan and are characterized by severe compaction, low organic matter, poor water retention, and limited crop productivity. Sustainable rehabilitation strategies for these soils remain underexplored. This study evaluated the potential of farmyard manure compost (FYM) as a soil amendment to improve physicochemical properties, soil water retention, and sorghum (Sorghum bicolor L.) performance in degraded Naga’a soil. Aerobic composting of FYM was conducted for two months under controlled moisture and C/N ratio conditions, producing a mature compost with enhanced organic carbon, nitrogen, and water-holding capacity. A pot experiment was conducted using five rates (0, 5, 10, 15, and 20 t ha−1) of the produced compost alongside a mineral NPK treatment, assigned in a randomized complete block design. Compost application significantly (p ≤ 0.05) increased soil organic carbon, total nitrogen, total phosphorus, saturation percentage, and water-holding capacity compared with the control and NPK treatments. The highest compost rate (20 t ha−1) improved soil water-holding capacity by approximately 20% and organic carbon by over 90% relative to the control. Sorghum dry matter production and plant nutrient uptake (N, P, K, and Ca) increased significantly with compost rate, while total seasonal irrigation water requirements declined. Water productivity improved progressively with compost addition, reaching a maximum increase of 60.5% at 20 t ha−1 compared to the control. Overall, FYM proved effective in restoring soil functional properties, enhancing water-use efficiency, and improving sorghum growth. The results highlight the valorization of FYM as a sustainable, low-cost strategy for rehabilitating degraded non-cracking soils in arid and semi-arid environments.