A note on the estimation of nutrient value of cattle slurry using easily determined physical and chemical parameters

The composition of cattle slurries can vary greatly due to factors such as farm management,meteorology, animal diet and housing system. Thus, when spread on land, the precise fertiliser value is usually unknown. In this study, 41 samples of cattle slurry from farms in Co. Wexford, were analysed for electrical conductivity (EC), pH, and for concentrations of dry matter (DM), total Kjeldahl N, total P and total K. Correlations between physico-chemical properties (pH, EC, DM) and nutrient concentration showed that DM and EC could be used to estimate nutrient concentration. Generally, DM was the best estimator of N (R2 0.75) and P (R2 0.82), while EC was the best estimator of K (R2 0.73). EC was also highly correlated with N concentration (R2 0.67). The proportion of variation accounted did not substantially increase when multiple regression was used.