Oversowing white clover in grasslands for improved dairy production

Jim White manages a dairy herd of over 200 cows on his family farm in Clonlaha, County Tipperary, using a spring calving system. He has successfully integrated white clover into his grazing swards through over-sowing, improving dry matter yield by around one tonne per hectare and boosting milk solids by 20–40 kg per cow. The practice enhances herbage quality in summer and autumn, increases dry matter intake, and reduces nitrogen fertilizer use by 30–50 kg N/ha through atmospheric nitrogen fixation. Over-sowing is carried out in April after a recent graze, using an earthseed, with paddocks selected for high perennial ryegrass content, low weed pressure, and good soil fertility. Soil pH is maintained above 6.5, and P and K indices are kept above 3. To support establishment, pre-grazing sward mass is kept below 1,000 kg DM/ha by grazing every 10 days. This strategy has enabled consistent clover establishment and reduced nitrogen inputs by 30–40 kg N/ha, with full farm-wide adoption still in progress.