Where paddocks have been reseeded this autumn, getting a good reseed establishment is essential to the success of the job.
Where a good reseed establishment is not achieved, undesirable plant species can take hold in the reseeded paddock which of course will have a negative impact on the paddock productivity.
Earlier this month, the College of Agriculture Food and Rural Enterprise (CAFRE) beef and sheep adviser Jonny Brown reminded farmers that reseeding is “a cost-effective investment”.
He said: “When carried out successfully, it will increase the amount of grass grown in a new sward compared to an old ley with the potential to reduce reliance on concentrates within an enterprise.”
He outlined a number of key points farmers should keep in mind to ensure a good reseed establishment rate.
Fields for reseeding should be selected on how they have performed over the growing season. Fields which have under-performed or fields that have been badly damaged by livestock or machinery should be a priority.
Once a field has been selected, it is important to consider some of the following points to ensure the reseed is a success:
- Are there any drainage issues to correct?
- Is there a compaction problem needing attention?
- Soil fertility status?
He said that addressing problems associated with waterlogging in a field “is key to the establishment of the new ley” and added that it is best to carry out all remedial work prior to cultivations beginning.
Where compaction issues in land need attention, he said: “The correct way to determine the level of compaction present is by digging a number of test pits throughout the field to determine the depth the compaction problem exists.
“Compaction within the top six to eight inches of the soil profile will be alleviated by ploughing, if it extends deeper in the soil profile then subsoiling may be a more effective option.”
Where soil fertility is an issue, he advised NI farmers to refer to Soil Nutrient Health Scheme (SNHS) soil analysis results if available and complete the CAFRE SNHS training to fully understand what the soil fertility status is”.
“If no recent results are available, then carrying out soil sampling is recommended. This should only be carried out if no artificial fertiliser or slurry has been applied in the previous three months.”
He added that farmers should pay particular attention to soil pH and added that soil at pH 5 is 10 times more acidic than that of pH 6.
“The optimum pH for grass clover swards is 6-6.5 for mineral soils.”
Where farmers are applying lime, he said: “Lime is best applied after ploughing but before secondary cultivations for a reseed.
“Application before ploughing causes lime to be buried excessively deeply in the soil leaving the surface of the soil acid. This can affect the uptake of nutrients such as phosphorus which is essential for root development.
“Desiccating the existing sward with the correct product at the correct rate must be carried out carefully to remove competition for the new seeds against old grass and weeds.”
He added that the earlier the new grass is sown the better and that “like all new seeds, grass and clover are sensitive to soil temperature, so establishing the new growth prior to soil temperatures dropping is critical”.
The best cultivation method should be considered “on a field-by-field basis” and “where drainage work has been carried out, the ground has been poached or damaged by machinery then ploughing may be essential but various methods of minimum tillage/direct drilling could be an option if conditions are suitable”, according to the CAFRE advisor.
Selecting a grass seed mixture
The CAFRE advisor said that selecting a grass seed mixture “should be carried on an individual farm basis”.
“If the field is for silage, look for varieties with traits for high D-value and dry matter yield. Remember that heading dates approximately ten days after your planned cutting date are required to ensure you achieve maximum silage quality.
“A close range of less than seven days between the heading dates of the varieties within the mixture will allow for better management of your sward,” he explained.
Commenting on seed variety’s, he said that diploid varieties “are predominately for increased ground cover while tetraploids have a tall growth pattern and can be more open on wetter soils”.
“The management of your sward post sowing will determine the inclusion of clover. Clover safe post emergence sprays will be required or alternatively clover can be stitched in six weeks after spraying,” he added.
