Nutrient Balance and Soil Condition: Effects on Dairy Grassland Productivity

Global demand for livestock products is increasing and encourages farmers to expand and intensify their grassland systems by increasing stocking rates and extending the grazing season. In this post milk quota era the European dairy industry, which is the dominant farming system in a number of northern European countries, has responded by increasing milk production on farms and the volume of milk processed. However, while intensification may enhance production volume and economic growth, in the longer term it could also severely impact soils and environment if not managed carefully. Grass production between and within farms can vary widely depending on a number of soil, climate and management related factors.

Irish dairy farming is mainly based on increasing the conversion of grass into animal milk and genetically selected animals to provide higher milk production from grazed grass as the main feed input. Dairy farms have expanded rapidly over the last number of years and extra grass must be grown and utilised to avoid increases in supplementary feed use. However, on farms negative nutrient balances due, in part, to lower than optimum fertiliser use, has led to declining grassland soil fertility over the last decade, and the production potential of grassland soils in Ireland is being slowly eroded. Therefore, grassland farmers face significant challenges in maintaining productive, economically viable and sustainable farming businesses into the future. ‘One soil does not fit all’ and the development of fertiliser application strategies requires appropriate field-by-field or paddock scale information on soil fertility, soil type and grass sward productivity levels. This information is critical for increasing fertiliser use efficiency, maximising the potential of soil resources and minimising the potential losses of nutrients to the environment. To achieve these aims, increased knowledge of soil type differences, corresponding to nutrient behaviour across farms, will be required by the various actors working in the agri-industry.

D.P. Wall, Teagasc, Crops Environment and Land Use Programme, Johnstown Castle, Co. Wexford, Ireland.

O. Fenton, Teagasc, Crops Environment and Land Use Programme, Johnstown Castle, Co. Wexford, Ireland.

E. Clagnan, Teagasc, Crops Environment and Land Use Programme, Johnstown Castle, Co. Wexford, Ireland.

P. Tuohy, Teagasc, Animal and Grassland Innovation Programme, Moorepark, Fermoy, Co. Cork, Ireland.

P.N.C. Murphy, Teagasc, Crops Environment and Land Use Programme, Johnstown Castle, Co. Wexford, Ireland.

C. Buckley, Agricultural Economics and Farm Surveys Department, Teagasc, Athenry, Co. Galway, Ireland.

G. Bondi, Teagasc, Crops Environment and Land Use Programme, Johnstown Castle, Co. Wexford, Ireland.

28 pages, 10 figures, 4 tables, 68 references.