Assessment of the Effect of Glycine, Oxalic Acid and Nitrogen-Phosphorus-Potassium (NPK) Fertilizer as Nutrient Supplement Using Phosphate and Oxalic Acid as Indices

--------------------------------------------------------------------------------------------------------------------------------------------Abstract This study evaluated the release profiles of phosphate and oxalic acid in soils treated with oxalic acid a low molecular weight organic acid and glycine an amino acid compared with NPK fertilizer monitored over a period of 21 days. The soil treated with oxalic acid and glycine released higher phosphate and oxalic acid than that treated with NPK fertilizer. The soil treated with oxalic acid released higher phosphate than that which was treated with glycine while higher oxalic acid was observed in the soil treated with glycine rather than for that treated with oxalic acid. Significant effects were observed between the treatment and the length of time for phosphate release (P<0.05) while for the release of oxalic acid, there was no significant effect between the treatment (P>0.05) but with increase in length of time (P<0.05). This demonstrates the efficient ability of oxalic acid and glycine as substitutes for phosphate fertilizers.