Nutrient budgeting and soil fertility status in intensive rice-wheat cropping zones

Abstract:

Farmers in the Indo-Gangetic Plains face a practical dilemma every season: apply more fertiliser and risk profit erosion, or hold back and risk yield decline from nutrient mining. This research constructed nutrient budgets for nitrogen, phosphorus, and potassium across 60 rice-wheat fields in two districts of eastern Uttar Pradesh—Ayodhya and Ambedkar Nagar—during 2021–22 and 2022–23. Input-output analysis showed a mean N surplus of 34.7 kg ha⁻¹ yr⁻¹ but a K deficit of −41.3 kg ha⁻¹ yr⁻¹, indicating that farmers over-apply nitrogen while neglecting potassium. Phosphorus was near-balanced (+6.8 kg ha⁻¹ yr⁻¹). Available soil K declined by 18.4 mg kg⁻¹ over two years in plots with persistent K deficits. Apparent N recovery was only 38.2%, suggesting large losses via volatilisation and leaching. These findings call for rebalancing fertiliser use—reducing N by 15–20% while adding 40–50 kg K₂O ha⁻¹—to arrest potassium depletion without sacrificing yield.