Improve Forage Production Through Reseeding this Spring

1st April 2022

Coming into the spring you may be thinking of reseeding. High quality reseeds can carry more stock, increase animal performance, regrow faster, use nitrogen fertiliser more efficiently and grow more grass throughout the year. Old permanent pasture is up to 25% less responsive to nutrients including nitrogen, than a perennial ryegrass dominated sward, which is extremely important with the current price of chemical nitrogen.

Reseeding in the spring as soil temperatures and hours of sunshine increase will help the grass/clover establish well. The reseed can then be grazed multiple times over the summer months allowing the sward to tiller producing a dense sward.

The first step is to identify swards for reseeding, you should reseed poorer preforming fields and those with low levels of desirable species such as perennial ryegrass. When the sward contains less than 60% productive species action is required to increase production. If there is 60% or less productive species in the sward overseeding is a good option to increase the production of the sward. However, if the sward contains less than 50% productive species a full reseed is best to increase productivity and efficiency. Perennial ryegrass is the main productive species we look for in swards it can be identified by the red colour at the stem base alongside having folded leaves emerging from the leaf sheath.

Before sowing grass seed, it is important to ensure the field conditions are optimum for sward establishment. This includes looking at soil fertility and correcting any drainage or compaction issues. Soil fertility can be determined from recent soil analysis. The soil pH should be a minimum of 6.3 for grass establishment and 6.5 for clover swards with P&K indexes of 2 or 3. If a soil has a phosphorus index 2, it will require 40 units of phosphorus and an index of 2- for potassium it will require 48 units of potassium, 48 units of nitrogen would also be required, however if the new sward contains clover this nitrogen is not needed.

For a full reseed the sward should be sprayed off using glyphosate and cultivated 7-10 days later with a plough or disc harrow, any lime needed should then be applied and a fine firm seed bed prepared. The fertiliser should then be spread, followed by the grass seed, and finally the field should be rolled to ensure good seed soil contact. As the reseed establishes, check for weeds, and apply suitable herbicide as required, a biostimulant at this stage will encourage rooting and reduce any herbicide shock to the grass. The first grazing of the new sward can take place as soon as the new plants do not pull out of the ground, ideally with young stock or sheep. A new spring reseed will grow more grass in the year of establishment than the old sward it replaced disproving the fear of removing land from production.  

Fane Valley stock a range of quality grass seed mixtures for grazing, silage production or other specialist requirements. To find out more about reseeding call into your local store, contact your Fane Valley representative or call the Agronomy & Forage office on 028 9261 0485.