Long-term application of FYM and fertilizer N improve soil fertility and enzyme activity in 51st wheat cycle under pearl millet-wheat

Our study from an ongoing research experiment initiated in Rabi 1967 at the Research Farm of CCS Haryana Agricultural University, Haryana, India, reports that during the 51st wheat cycle in pearl millet-wheat sequence, adding FYM in both seasons significantly impacted various soil parameters at different wheat growth stages compared to the rabi season. The application of 15 t of FYM ha^-1 resulted in a considerable increase in dissolved organic carbon content (9.1-11.2%), available P (9.7-12.1%), and available S (12.6-17.1%), DHA levels by 7.3-22.0%, urease activity (10.1 and 17.0%), β-Glucosidase activity (6.2-8.4%), and APA activity (5.2-10.6%), compared to 10 t FYM ha^-1. Application of N₁₂₀ exhibited a considerable improvement in DHA (11.0-23.2%), β-Glucosidase (9.4-19.2%), urease (13.3-28.3%), and APA (3.3-6.2%) activity compared to control (N₀). At stage 3, the box plot revealed that 50% of the available N, P, and S values varied from 223.1 to 287.9 kg ha^-1, 53.0 to 98.2 kg ha^-1, and 50.0 to 97.6 kg ha^-1, respectively. Principal component analysis, with PC1 explaining 94.7% and PC2 explaining 3.15% of the overall variability, and SOC had a polynomial relationship with soil characteristics (R² = 0.89 to 0.99). Applying FYM₁₅ × N₁₂₀ treatment during both seasons proved beneficial in sustaining the health of sandy loam soil in North-West India.