Low-molecular-weight Organic Acids As a Phosphorus Fertilizer Alternative for Vegetable Production in Calcareous Soil Regions

The purpose of this study was to investigate low-molecular-weight organic acids and their ability to solubilize native phosphate (P) from calcareous soil regions as a possible alternative for commercial P fertilizer.  As a highly dependent P-nutrient crop, Solanum melongena (eggplant) was employed in a pot study and field grown using two distinct soil types native to the Central Texas region.  S. melongena was grown in two distinct soil orders: Using mollisols and vertisols, each soil pot was treated with two molar concentrations for each acid using oxalic (0.1 mM, 100 mM) or citric acid (0.1 mM, 100 mM).  The control received the recommended triple superphosphate [Ca(H₂PO₄)₂] for eggplant production.  Equal parts of urea [CO(NH₂)₂] fertilizer was applied to all pots.  After crop maturity, fruit was harvested in weekly intervals for five weeks and measured to determine quantity and quality, based on weight and USDA standards.  P solubilization from each pot was measured using a spectrophotometer (mg/L).  A factorial MANOVA further determined statistical significance between organic acid application, P solubility and fruit biomass production, p> 0.05.