Copper and pH Effects on Soil Nitrogen Mineralization after Compost Application

Abstract

The study looked to evaluate the effects of two levels of copper in a sandy clay loam soil (of the order Aridisol), and of five levels of pH, on the velocity of nitrogen mineralization after incorpo- rating compost. The experiment underwent 10 treatments: five pH levels, and two copper levels (251 mg kg¯‘ and 345 mg kg¯‘) with five replications. Planter pots were set as the experi- mental unit, and were maintained in a greenhouse for 108 days at a temperature of 25 °C. They were watered to maintain field capacity. The nitrate (NO3¯) and ammonium (NH ) contents were measured five times at 0, 27, 54, 81, and 108 days after compost application. Analysis of variance of data and Tukey test (p≤0.05), showed that the factors copper concentration and time affected ammonium and nitrate concentrations. It can be concluded that time is the factor of greatest importance in the process of organic-N mineralization in soils with medium to moderately high total levels of copper. Time factor weakly interact with the soil copper content, and is independent of the pH in a range from moderately acid to moderately alkaline.