By Jeffrey S Graybill
The Agronomy Guide states that late summer (mid-August to early September) forage seedings in Pennsylvania are generally the most successful. Cool evenings and early fall rains provide an ideal environment for grasses. In addition to establishing new grass and legume fields during this time we should be looking at and evaluating established pastures and hayfields.
Over-seeding vs. Total Renovation:
One popular practice is no-till renovation of existing fields and pastures. A well-maintained no-till drill can attain the proper depth and seeding rates for all common forage grasses and legumes. Renovation can be as simple as over-seeding overgrazed areas and areas where broadleaves have invaded, to total renovation in which a glyphosate treatment is often used to kill all existing species followed by reseeding with desired species. Some advantages of no-till establishment and renovation are erosion control, time/labor savings, and ease of establishment.
Fertility management is a key factor whether you are preparing an existing field for winter or renovating a field. Soil testing, applying lime, Nitrogen, Phosphorus and Potash as indicated on that soil test will increase growth, recovery rates and winter hardiness. One ton of dry grass hay contains approximately 40 lbs. Nitrogen., 13 lbs. Phosphorus and 60 lbs. Potash. Fall is an excellent time to replace these nutrients. Manures also make an excellent fertility source and can be applied as a top dress before or after no-till seeding. Liming to reduce soil acidity also increases nutrient availability, which increases the competitiveness of desired species and is an excellent source of Calcium and Magnesium. In long term hay and pasture fields watch for surface acidity by taking a shallow (2”) soil test in addition to the standard 8” sample.
Select a species adapted to your soil types and management practices. Also, consider your end use, intended markets, desired yield, and quality. Improved varieties will make a difference in situations where disease has been a problem and high productivity is sought. Consider planting mixed species where you have variable soils. Most seed companies have pre-mixes for specific situations and conditions.
Clipping pastures before over-seeding or total renovation will help with weed control and allow increased light penetration aiding in the germination and growth of the new seedlings. Clipping and removing excess fodder in conjunction with fertilizing will help thicken up existing stands and speed establishment of new seedings. Chemical control of existing weeds prior to over-seeding can be tricky, as products such as 2,4-D and Dicamba, which control broadleaves, have a 30-day planting delay after application. They are however two of the most used products in grass hayfields and pastures prior to over-seeding.
Glyphosate is generally the product of choice when doing a total renovation. Glyphosate is non-selective, highly effective, and you can reseed immediately after application.
Now is the time to evaluate the condition of your pastures and hayfields and decide upon a plan of action to keep them producing the desired quantities of high-quality forages.Source : psu.edu