can save cash, but
PUT off by the cost of a total reseed? Increasing numbers of producers are renovating old pastures instead. But success depends on establishing why an old sward is deteriorating, before taking action, says Oliver Seeds Francis Dunne.
"When times are hard, re-seeding costs of £100/acre can put people off. Renovation using overseeding techniques can be an alternative, but planning is often lacking. When it fails, producers frequently blame seed quality, but soil structure and nutrition could be the underlying problem."
More grass yield potential is locked up by poor soil structure than by any other factor, said Mr Dunne. "The roots of a plant can be compared to an animals mouth – both take in nutrients. Compacted soil structure is the equivalent to having your jaw wired.
"Improving soil structure can increase grass yield by 25%. Depending on the depth of compaction, this can be done using harrow combs, spike aerators, tined aerators or sub-soilers."
Conducting a soil analysis before reseeding is also important, said Mr Dunne. "The surface layer, key to renovation techniques, is often the most acidified, particularly where high rates of fertiliser have been used. Nutrient deficits and pH should be corrected prior to sowing."
Finally, weeds and pests should be considered, suggested Mr Dunne. "Competitive perennial weed species can seriously limit the success of most sown species. Couch, black grass, black bent and high populations of broad-leaved weeds, such as creeping buttercup, must be destroyed before overseeding.
Avoiding pest damage can be tricky, he said. "You are establishing seedlings in an environment already populated by the species most likely to attack them. Slugs, frit fly, sitona weevils and leather jackets attack at different times of year. Conventional producers can consider chemical control, but for organic producers, it is best to avoid risky times of year, which usually means reseeding in spring or early summer." *
Correct soil structure.
Tackle weeds and pests.
• Correct soil structure.
• Analyse soil.
• Tackle weeds and pests.