As we approach mid – September, Autumn reseeding is well underway. To reseed is an effective way to increase productivity on farms. High quality seeds can carry more stock, regrow faster, and helps improve silage. It can also increase live weight gain and uses nitrogen fertiliser more efficiently.
Farmers can also undertake this practice in Spring, but regardless of the time of year, it can be a costly procedure. According to Teagasc, swards with a low proportion of perennial ryegrass are costing Irish farmers in excess of €300/ha/year. However, reseeding can pay for itself within two years as the cost of reseeding is approximately €600/ha.
When reseeding, timing is critical. The success of the new sward depends on weather conditions. Farmers need to take weather into consideration. If weather breaks during the preparation process, a week or two can be lost so we recommend planning in advance and leave some extra time for delays.
The method of reseeding also impacts the success of the establishment of the swards. Key -considerations are the soil fertility and developing a firm seedbed. Soil testing may be beneficial to determine the best course of action.
Ploughing is the most common method. It creates good soil/seed contact and buries thrash and pests. It can help level and uneven paddock or correct drainage issues. Discing and one pass is another method. We advise farmers to give the paddock two to three runs with a disc going in different directions. Then go in with the one-pass or a power-harrow machine. This helps to break up the old sod; and to turn up enough soil to create a suitable seed bed. The last method is direct drill. This works best on paddocks that were tightly grazed or cut for silage. This method makes a slit in the ground in which the seed is placed and then covers it back over with the machine.
Post sowing management is equally as important as the sowing itself. Weeds must be kept at a minimum and the best way to do this is to encourage the new grass to tiller as much as possible. Tillers are stems produced by grass plants and these lead to overall establishment success. A successful sward is considered to have 10,000 tillers/m2.
The main areas that will increase tiller numbers are Nitrogen and grazing. Nitrogen should always be applied at seeding along with P & K. It is recommended to test soil as the results will impact the amount for each reseed. How to know when you can graze, pull the grass and if the roots don’t pull then the sward will have strengthened enough. Short grazing intervals are best, young light cattle or sheep will encourage tillering while also reducing surface damage in the field.
Post Emergence Sprays
Post emergence sprays are crucial to post sowing management. After you reseed weeds can appear, these need to be monitored. The best time to use a spray is 3 – 6 weeks after reseeding. Depending on the ground and type of soil, farmers should be aware that they may be limited in the type of post emergence spray that can be used. For grassland, farmers can choose a from a range of sprays but if you have grassland with clover the sprays you can use are limited as you don’t want to kill the clover. Once again, farmers who have grassland with clover that was previously tillage are also limited in the sprays they can use. Farmers is Derogation should be aware they have to put clover into the grass seed.
Reseeding followed by proper management with targeted fertiliser, spray and grazing will allow the sward to thicken and thrive leading to a well-established and successful reseed.
Farmers can contact their local Farm Relief Services office should they need help on the farm. Visit https://frsfarmreliefservices.ie/ for more information.