Autumn reseeding advice
Reseeding considerations: Many silage and grazing swards now contain high levels of weed grasses. These grasses are not only lower yielding than perennial rye-grass, but they also produce lower quality silage and grazing grass. Reseeding old pasture with the best perennial varieties available will increase silage energy content by 2.0 MJ ME/kg dry matter, allowing a substantial saving in meal feeding.
· Identify fields for reseeding. Base your decision on ryegrass content rather than the age of the sward. Ryegrasses are easy to distinguish from less productive grass like bents and meadow grasses. Once they drop to less than half the sward content you need to think about reseeding.
· Complete autumn reseeding during August or early September. This allows the old sward to be kept in the grazing or silage-making system right up to July or early August, if required. Warm soils mean better, more rapid establishment, providing there is sufficient moisture.
· Effective destruction of the old sward including established perennial weeds is critical to success. A full rate glyphosate spray is essential.
· Cultivations should produce a fine and firm seedbed to preserve as much soil moisture as possible. It is important to get the soil phosphorus (P), potassium (K) and pH status right. It is well worth having the soil tested and correcting any imbalances. Also check the ground for compaction and poaching and subsoil any suspect or damp areas to improve drainage. Otherwise, you will just encourage weed grasses, rather than the productive ryegrasses you have sown.
· Use only varieties from the Northern Ireland Department of Agriculture and Rural Development (DARD) recommended lists. The latest list is available in your local DARD office. For silage swards the choice of variety will be largely influenced by cutting date. For grazing swards, choose mainly intermediate and late heading varieties which will give a dense growing sward.
Grazing conditions have been challenging for a large part of the season in many areas of the Province. Heavy rain in early July did not help ground conditions or grass utilisation on many farms I visited in July. What lessons can we learn from these adverse grazing conditions?
· Grass is still the cheapest feed available for milk production, therefore make every effort to use it efficiently. However, where there is heavy localised rain, continuing to graze can have negative knock-on effects for herd management.
· You must assess your own situation and base decisions for daily herd management on:
· ground conditions
· cow condition
· grazing infrastructure
· forage stocks
· milk price
· Decisions based on the above parameters will ensure the herd is managed to the best of your ability.
Do you have enough forage? Is a third cut possible?
- Good growth in June and July has helped bulk up forage stocks. However, if second cut is in the silo, and you have good re-growth, consider another cut.
- Utilising slurry for third cut will help empty slurry tanks for the winter ahead. Make every effort to empty slurry stores.
- If 22,500 litres of cow slurry per hectare (2,000 gallons per acre) are applied by spread plate the nutrients available for grass growth are13.5 kg N: 27 kg P: 72 kg K.
- If the slurry is applied using trailing shoe 10 kg more nitrogen is available from the 22,500 litres. This is due to more efficient use of the nitrogen in the slurry.
By Conail Keown of the College of Agriculture, Food and Rural Enterprise. He can be contacted via email: [email protected]