• The composition of dirty water on dairy farms in Ireland

      Martinez-Suller, L.; Provolo, G.; Carton, Owen T.; Brennan, Denis D.; Kirwan, Laura; Richards, Karl G. (Teagasc, 2010)
      Considerable quantities of dirty water, composed of milking parlour wash-water, milk spillages, runoff from cattle yard areas and, possibly, effluent from silage and manure, are produced on dairy farms. In Ireland, dirty water from dairy farm facilities is normally managed by spreading on, or irrigation to, land. It has considerable potential to cause water pollution due to its high pH, 5-day biochemical oxygen demand and its N and P concentrations. The objective of the present study was to contribute to better management of dirty water on dairy farms by providing estimates of its composition using rapid methods that can be easily used on farms. During the experiment, 34 samples were collected from the facilities on the dairy farm at Teagasc, Johnstown Castle (Wexford), between 27 January and 1 May, 2006. Dry matter and specific gravity provided the best indicator of biochemical oxygen demand, total nitrogen and phosphorous, and micro and macro nutrients. The nutrient concentration of dirty water can be determined rapidly using either dry matter concentration or specific gravity, enabling farmers to include this information in the nutrient management plan for their farm.
    • A note on the estimation of nutrient value of cattle slurry using easily determined physical and chemical parameters

      Martinez-Suller, L.; Provolo, G.; Brennan, Denis D.; Howlin, T.; Carton, Owen T.; Lalor, Stanley T. J.; Richards, Karl G. (Teagasc, 2010)
      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.