Optimizing Mineral Fertilizer Use in Maize Cultivation: A Study on Biodigestate and N, P and K Fertilizers Integration

Abstract

Reducing mineral fertilizer use while maintaining crop productivity is crucial for sustainable agriculture. Field studies in 2022 and 2023 examined the effects of biodigestate application (0, 2,500, and 5,000 L ha⁻¹) alone and in combination with N, P, and K fertilizers on soil properties and maize performance. The experiments followed a factorial design with two years, three biodigestate rates, and nine NPK combinations (N1P1K1, N1P1K2, N1P2K1, N1P2K2, N2P1K1, N2P1K2, N2P2K1, N2P2K2, and a control N0P0K0). The nutrient rates were as follows: N1 = 60 kg N ha⁻¹, N2 = 120 kg N ha⁻¹, P1 = 30 kg P₂O₅ ha⁻¹, P2 = 60 kg P₂O₅ ha⁻¹, K1 = 30 kg K ha⁻¹, and K2 = 60 kg K ha⁻¹, arranged in a randomized complete block design with three replications. Results showed that biodigestate application improved soil fertility and maize growth compared to the control. The year 2022 had better soil chemical properties and higher yields than 2023. In 2023, applying 2,500 and 5,000 L ha⁻¹ of biodigestate increased grain yield by 13.43% and 20.92%, respectively, relative to the control, highlighting its residual effect. Integrating biodigestate with NPK fertilizers enhanced yields more than their individual applications, ensuring a balanced nutrient supply. The highest yield was achieved with 5,000 L ha⁻¹ biodigestate combined with N1P1K1. Biodigestate is an effective soil amendment that can improve maize productivity in poor soils while reducing dependency on mineral fertilizers. Its integration with NPK fertilizers offers a viable strategy for sustainable maize production.