No doubt most graziers know that I am a strong proponent of legumes in my pasture stands. Maybe that comes from many years of watching my legumes produce high-quality forage back during my conventional years of dairy farming.
My very first grazing of the dairy herd in 1992 was on alfalfa-orchardgrass mixtures that had been harvested for hay or haylage in my confinement dairy. All of my new pasture establishments since that time have included legumes. Early on, alfalfa was a large part of my mix, and I did several experiments with the early grazing varieties of alfalfa along with my orchardgrass or bromegrass.
My observations showed that the seedling alfalfa plants struggled to survive beyond the seeding year, either because of autotoxicity or lack of seedling vigor. In contrast, clover grew quickly and flourished, quickly becoming the dominant forage in the mix. Seed prices rapidly designated red clover as the most cost-effective legume to add to the pasture mix.
Our goal is to add seed every three years. Years ago we spin-seeded, and I have no problem with doing it that way. But we now have a Tye “Pasture Pleaser” drill that we bought used from the county, and feel we get better seed-soil contact. Our goal is a 60% “visual” legume stand, which means that when we look at a stand, we see slightly more legumes than grass.
I have used Brookside Laboratories agronomy consultants since 1984, and early in my grazing experience they recommended up to 150 units of nitrogen in three applications during the grazing season to improve the grass production. My nitrogen source has always been ammonium sulfate due to a sulfur shortage on this farm.
I’ve always been one to use check strips, and we soon realized that a slightly greener color was all I realized from the added N. Production didn’t seem to be any higher. I will admit that I didn’t do as much pasture yield evaluation then as I do now, but visual observations by myself and forage specialists didn’t detect much difference. In 1994 we decided to do a test, and split each of 30 small paddocks into three test strips. One strip received 150 units N in two applications, one got 75 units in two applications, and the other received none. After three years of this trial, the only difference observed was fewer legumes in the areas that received 150 units of N.
The test convinced both my consultant and I that nitrogen is a poor investment when legumes were at least 50% of the visual stand. All of these experiments were on sandy loam soils. But what about other soil types?
We also have 40 acres of muck soils. In 1993 we seeded them to reed canarygrass and a combination of alsike clover and birdsfoot trefoil. The canarygrass and birdsfoot were slow to establish, so the alsike dominated. For the first two years we were very content with that mix. But alsike is a true biennial, and within two years it had nearly disappeared. I have made several attempts to reestablish alsike in these paddocks, with no success. Since muck soils are high in organic matter, it is possible for plants to utilize a large amount of natural N. At the same time, our experiments have shown commercial nitrogen to provide some benefits on these soils. In fact, in two years when we were quite droughty the canarygrass, fertilized with plenty of nitrogen, was our drought insurance.
We also have about 60 acres of muck on our newly rented farm. Those areas were seeded to canarygrass and kura clover in 2002, but a the July 4 flood destroyed it last year, so we can only hope that this mix will work. The balance of the newly leased farm is seeded with high levels of legumes. We had a chance to see what some of the new ladino clovers could do as a major portion of these former corn fields, and after one season of good grazing we are quite impressed.
So here is what I’ve learned about legumes in managed grazing. I feel legumes provide better-quality forage than most grasses that will reliably grow under adverse conditions. This may be one reason why I can successfully feed relatively little grain (6 lbs./day) to milk cows on pasture. Legumes are easier to maintain on lighter soils, and they are more important to have in these paddocks in times of dry weather when grasses won’t grow as well. Clovers are tougher to grow on wetter soils with high organic matter, and the greater levels of natural nitrogen in these soils reduce the need for N fixed by legumes. Grasses will respond better to commercial N on these soils.
These are the observations from my farm, and yours may be somewhat different. Why do many people have trouble maintaining legumes in their paddocks? The reasons probably vary. But I believe that anytime you push grasses to the top limit of fertility, you crowd out the legumes.
I feel it is worthwhile to try to maintain legume populations where possible. With nitrogen prices based on petroleum costs, I expect ammonium sulfate to be over $150/ton this season. That means 100 units would cost about $37/acre. Meanwhile 8 lbs. of red clover at $2/lb., and 2 lbs. of ladino at $3/lb., costs $24 an acre. This seed is capable of providing a 60% legume stand in a pasture of bromegrass, orchardgrass or tall fescue. Add the cost of a no-till drill, and your first-year cost is about the same as 100 units of N. The value comes in the second and third year, when no additional seed is needed.
The $37/acre for commercial N or clover seed would buy only half a ton of hay. Based on our experience, I don’t believe yields in our sandy upland soils would increase by that much if we bought the N. However, I do think that we are adding more than half a ton of forage production with the clover. And it is high-quality forage.
And clovers offer us an opportunity to simplify a possible transition to certified-organic milk production. Since only our 40 acres of muck soil has had fertilizer recently, we should be able to certify the balance of the farm once we pass the three-year application dates on the rented farm around June. Then my only concern will center on whether the organic processor we’re talking with will accept seasonal milk production. I’d really hate to give that up.