Regular successful reseeding is an essential part of livestock farming to maintain support for high levels of milk and meat production. But to maximise the long-term performance of new grassland, reseeding must be carried out correctly.
“Reseeding represents a significant financial investment, and you gain the most benefit from it when the reseeding process is well managed,” explains Germinal Ireland’s technical sales manager, Diarmuid Murphy.
“Now is a good time to review your approach. Compare it against our 10-point action plan and think about improvements you could make to your current reseeding strategy.”
1. Soil test for successful reseeding
Before you start, test your soils to identify any soil nutrient deficiencies, focusing on pH, P and K levels. To boost future grassland performance, create a targeted input plan to address deficiencies highlighted by these tests.
Take soil samples which best represent the true make-up of a field, avoiding areas where large numbers of livestock congregate, such as next to hedges.
2. Kill off the old sward
After soil testing, prepare to reseed with a ‘clean slate’. Create the maximum amount of room for new, higher performance grass varieties in the sward by taking out inefficient old pasture and weeds.
Spray with glyphosate to kill off the old sward, using the prescribed amounts of product and water. Using the correct proportions moves the glyphosate from the tips of the plant, deep down into the root, ensuring a good kill.
3. Prepare the seedbed
Give old, dead grass plenty of time to decompose properly after spraying, before beginning cultivation to maximise seed to soil contact and provide the best chance for successful germination. Focus on creating a fine, firm and fertile seedbed.
Select the cultivation method to best suit your soil type and crop rotation. Ploughing is a popular choice as it can level-up ground, improve drainage and create a finer seed bed. But minimum cultivation methods are better suited where ground has stone or rock near the soil surface.
4. Select the best grass varieties
The grass varieties you choose need to suit your farm type and best meet your requirements. Ask yourself how the reseeded field will be used. Some perennial ryegrass varieties are better suited for grazing, others for silage.
Select varieties from the DAFM recommended list and 2021 Pasture Profit Index. These are proven under Irish conditions and give you access to the very latest genetics. The difference in performance between the highest and lowest ranked varieties is substantial.
5. Sowing grass seed
To optimise germination rates and ensure successful reseeding, aim to sow grass seed at a depth no greater than 10-15mm at a rate of 14kg/ac. Farms in derogation must include 1kg/ac coated clover (0.6kg/ac uncoated clover seed).
6. Roll well after sowing
Rolling is an important piece of the reseeding ‘puzzle’, as consolidating the seedbed gives good soil to seed contact. This allows seed to absorb water from the soil and prevents moisture loss during periods of hot weather.
7. Apply fertiliser pre-emergence
Once rolling has been carried out, refer back to your soil test results and input plan. Apply lime and fertiliser to achieve an optimum P and K index of 3 and pH level of 6.2 – 6.5.
A general rule of thumb is to spread three bags of 10:10:20 (nitrogen: phosphate: potassium) fertiliser and 2t lime/ac for new grassland.
8. Spray post-emergence
Problem weeds germinate as a result of soil disturbance during reseeding. Even at low populations, they compete for light, water and space, so easily impact grassland productivity.
Dealing with them is much cheaper and quicker when they are young, so spray five to six weeks after sowing. Where clover is included in a grass mix, use a clover-friendly spray or be prepared to stitch in clover at a later date.
(NB. Since October 2020, it has no longer been possible to buy clover-safe herbicides and any already on-farm, must be used by October 2021.)
9. Monitor for pest attack
Juvenile grass swards are particularly susceptible to pest attacks. These can cause significant levels of damage and diminish long-term performance.
Monitor pest damage and take immediate remedial action if required. Leatherjackets, slugs and frit fly are the most common culprits.
10. Graze new reseeds
Once a new ley has established, graze it lightly to encourage thickening and tillering. Check if the grass is ready to graze by pulling at a handful of grass leaves. If the plant and roots pull up, it is too early, but if only the leaves tear, the grass is ready to graze. Graze young reseeds regularly at low covers.
For more information on quality reseeding, or to shop Germinal grass mixtures, click here.