Abstract

Agricultural waste represents a significant untapped resource for nutrient recovery in circular economy systems. This comprehensive study examines phosphorus (P) and potassium (K) recovery potential from crop residues, livestock manure, and processing by-products through innovative extraction technologies across multiple agroecological zones. Anaerobic digestion coupled with struvite precipitation achieved 85% P recovery efficiency from dairy manure, while thermal pyrolysis of rice husks yielded biochar with 12% K content suitable for direct soil application. Advanced composting processes demonstrated sustainable nutrient cycling with minimal environmental impact, recovering 78% of available P and 82% of K from mixed agricultural residues. Economic analysis reveals cost-effective implementation at farm scales exceeding 500 hectares, with payback periods of 3.2 years for integrated systems. The integration of precision agriculture monitoring systems optimizes nutrient application timing and reduces synthetic fertilizer dependency by 40% while maintaining crop yields. Emerging technologies including membrane filtration, ion exchange resins, and electrochemical recovery show promising results for producing concentrated nutrient solutions with recovery efficiencies exceeding 90%. Environmental benefits include 35% reduction in water eutrophication potential and 28% decrease in greenhouse gas emissions compared to conventional waste management. Policy frameworks supporting circular nutrient management could enhance agricultural sustainability and contribute to global food security goals. This research provides critical insights for sustainable intensification while addressing phosphorus scarcity and potassium availability challenges in modern agriculture.