Description

Practice asbtract

Jim White and his family farm in Clonlahy, Co Tipperary. Jim runs a dairy herd with just over 200 cows in a spring calving system. Jim began incorporating white clover in his grazing swards through over-sowing and reseeding in the last number of years. White clover can increase the tonnes dry matter grown (+1 t DM/ha), increase animal performance (+20-40 kg milk solids/cow) as it is a higher quality feed, and it can reduce the need for chemical nitrogen (-30-50 kg N/ha). The benefits of white clover tend to occur from May onwards as sward white clover content increases. Specifically increased herbage quality compared to grass-only swards in the summer months, increased dry matter intake in summer and autumn, higher milk production, nitrogen fixation from the atmosphere making it available for plant growth and reducing the requirement for nitrogen application in the summer.

Over-sowing is a simple and low cost method of introducing white clover into swards. Success is very much dependent on soil fertility, weather conditions at sowing, soil moisture, post-sowing grazing management and competition from the existing sward. Suitable paddocks for over- sowing are those with good soil fertility, high perennial ryegrass content and low weed content. Jim selects his paddocks to oversow by ensuring the soil fertility has a pH greater than 6.5 and P and K index over 3. Paddocks are oversown, by Jims farm machinery contractor in April on a freshly grazed sward using an earth seeder. After the seed is set Jim then ensures the pre-grazing yield of the swards remains under 1000 kg DM/ha (grazed approximately every 10 days) for the rest of the summer grazing season. This has allowed Jim to successfully establish clover for the following grazing season in an established sward, the use of clover has allowed Jim to reduce N input by between
30-40kg N/ha. However not all of the farm has fully established clover content and this is an ongoing objective.

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