Evaluation of specific gravity and electrical conductivity for determining nutrient concentrations in suspensions of poultry manure

With increasing concern for the pollution potential of farm wastes, there is a corresponding need for rapid and robust methods of analysis for animal manures. In order to study the rapid testing methods based on the relationship between nutrient concentrations and physicochemical properties, diverse samples (n=105) were used in this study. The results indicated strong linear relations between specific gravity (SG) and total phosphorous (TP), total nitrogen (TN), volatile solids (VS), copper (Cu), iron (Fe), zinc (Zn), and magnesium (Mg) concentrations (R2=0.80, 0.90, 0.91, 0.68, 0.71, 0.66, 0.77, respectively). Relationships between electrical conductivity (EC) and Sodium (Na), ammonium nitrogen (AN), and total potassium (TK) were significant with R2 values of 0.62, 0.85 and 0.68. Therefore, the hydrometer and conductivity meter can estimate rapidly nutrient concentrations of layer manure.