Effect of organic fertilization with NPK on organic matter and maize yield in degraded soils

Abstract

The incorporation of organic materials of animal or plant origin into soils has been shown to improve their physical, chemical, and biological conditions. The availability of cachaza (CA), a residue from the sugar industry, represents an average of 5% of the total sugarcane milled in the process. The use of this product as a fertilizer reduces pollution in accumulation zones and simultaneously improves soil fertility. In this study, cachaza combined with inorganic N, P, and K fertilizers was applied to two soils in the state of Yaracuy: alkaline and acidic. Its influence on soil organic matter and corn yield was evaluated, and optimal and economical combined doses were established. Field experiments were conducted using a Rotatable Central Compound Response Surface Design (RCSD), starting with central doses of 160 N kg ha⁻¹, 120 P₂O₅ kg ha⁻¹, 80 K₂O kg ha⁻¹, and 2000 CA kg ha⁻¹. The results obtained indicated that organic matter content increased in both soils with the applications of N and CA, without exceeding deficiency levels. Crop yield also increased with the application of bagasse, with a better response in the alkaline soil. The optimal and economical doses were found to be around 3000 kg/ha of CA, 200 kg/ha of N, 200 kg/ha of P₂O₅, and 90 kg/ha of K₂O.