It’s a common complaint in the haymaking business. “That field used to make 40 rolls per acre and now I do good to get 25!” Or “that field used to make the best hay and now it’s just a bunch of weeds.” The numbers and details may change, of course, but you get the point. Many of our hayfields just aren’t what they used to be.
I liken it to the difference between a symptom and disease in my kiddos. When one of the girls gets a fever and we take her to the doctor, the diagnosis is never “fever” since that is only a symptom. The diagnosis is the disease itself, i.e. ear infection, strep throat, flu, etc.
In hayfields, and pastures too for that matter, weeds and lower production are symptoms of a larger disease. For pastures, the disease might be overgrazing, soil compaction, or poor drainage. In hayfields, there are 2 big diseases I have noticed.
Disease 1 is poor fertility. Taking a hay crop off a field removes a lot of nutrients. For example, a 3.5 ton yield of tall fescue removes 135 lbs of N, 65 lbs of P, and 185 of K. If those nutrients aren’t replaced, production will eventually suffer. A grain farmer wouldn’t expect 200 bushel/acre of corn without fertilizing, and grass farmers can’t expect high yields without fertilizing either.
Having said that, I am well aware of current fertilizer prices and how they have skyrocketed. With a limited budget, I’d start with a $15 soil test from the UT lab which on a 20 acre hay field test every 3 years will cost you $0.25/acre. Following those results will ensure you aren’t applying more fertilizer than the crop will use.
I’d then spend money on lime if the soil test calls for it. A low pH ties up nutrients, making them unavailable to the plant. Lime raises the pH, making the fertilizer you apply more efficient. Keep in mind that many of the products you see marketed online to apply on fields with low pH don’t actually raise the pH. I’d recommend sticking with lime.
Be careful about cutting back too much on P & K. Many producers do a good job of applying N on hayfields since we can see the quick top growth it gives, but P & K affect the roots and overall plant health. Neglecting them can have big consequences down the road. Many of the broomsedge hayfields we test are low in these nutrients.
Disease 2 is disc mowers. We love using them and they have significant advantages over sickle bar mowers for sure, but one big problem is cutting height. A disc mower can cut lower than some lawn mowers and this repeated “scalping” of hayfields is a big reason fescue is dying out. Newly established fescue should never be cut lower than 4”, and established fescue shouldn’t be cut lower than 3”, although 4” would be preferred.
Repeated cutting of cool season grasses at a low height will deplete energy reserves and limit root growth. Cutting higher not only helps this issue but also leaves more green tissue for photosynthesis which allows the grass to grow back faster. It also helps the nutritional quality of the hay as you are cutting less of the stem and not adding as much dirt and debris.
I think curing these 2 diseases would go a long way towards improving the yields on our hay fields. Keep them in mind as you enter the haymaking season, and please reach out to our office at 615-735-2900 if you have questions or need help with soil testing.
