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Pasture improvements for your spring to-do list

Jim Gerrish Published on 29 January 2015
dragging the pasture

With spring right around the corner, you may be thinking about what needs to be done to bring your pasture vigor and productivity up a notch or two.

Fertilizing, dragging pastures, brush control or overseeding legumes may be on your list. Maybe that fence project you’ve been putting off has moved up the priority list. What about those stock water projects?

With everything else that comes at you in the spring, how do you go about deciding which of these tasks you should tackle and which are going back to the back burner again?

Do you base it on what is most likely to actually make you money or is whatever you most enjoy doing more important to you? Or do you just do what everyone else in the neighborhood does because that’s what we’ve always done here?

Believe it or not, some practices have quite a bit higher likelihood of paying off than do some other common spring activities. Let’s start with dragging pastures as an example.

The expected benefit is breaking up and scattering manure piles so they break down more quickly and nutrients are released back into the soil for the new season’s growth. In some parts of the country, it is also believed to reduce the presence of both internal and external parasites.

Even though farmers and ranchers have been dragging pastures for generations, there is very little evidence to support any economic benefit from the practice.

Manure piles are actually decomposed from the bottom up, and maintaining tight soil contact with the pile accelerates the breakdown. Scattered fragments of manure are slow to degrade due to lack of soil contact.

So why do cattlemen keep dragging those pastures? It does make the pasture look prettier, and we can see that we’ve done something as all those big, black piles of manure that accumulated over the winter months vanish behind the harrow. Was it a profitable use of our time? Probably not.

In the eastern half of the U.S., broadcasting legume seed during late winter and using the natural freeze-thaw cycle of the soil to incorporate the seed is a common practice. It works quite well for most clover species and lespedeza. In some areas, birdsfoot trefoil and alfalfa can also be seeded this way.

Almost every study that has ever been done looking at the economics of frost-seeding clovers indicates this has a consistently good payback in real economic terms.

Interseeding legumes Interseeding legumes has a couple of benefits that can translate to big dollars. A good stand of legumes can add more than 100 pounds per acre of nitrogen (N) to the soil each year through N-fixation.

At today’s fertilizer prices, that can be worth anywhere from $60 to more than $100 per-acre cost savings compared to adding commercial N-fertilizer.

Legumes also provide a nutritional boost to livestock, resulting in heavier weaning weights and higher rates of gain on stockers compared to N-fertilized grass pastures.

The nutritional response is amplified if the base pasture is endophyte-infected tall fescue, as the added legumes also serve to dilute fescue toxicity. Adding another 50 pounds or more to each weaned calf by reducing the effects of fescue toxicity gives a quick return on money invested in legume frost-seeding.

Sometimes broadcasting legumes into predominately grass pastures is done at the same time as dragging pastures in an effort to help cover the seed.

There are a few research trials that have shown the broadcast-and-harrow approach does provide more consistent results than simply broadcasting seed on a pasture. This benefit is generally seen when seed is scattered after soil temperature has warmed up and is no longer freezing at night.

Spring fertilization is a common practice on many farms. There is still something almost magical about watching the grass turn green and start growing in response to applying a good shot of N fertilizer. If you can see it happening right in front of your eyes, it has to be profitable, doesn’t it? Not necessarily so.

An assessment of grazing records comparing fertilized and non-fertilized smooth bromegrass pastures at USDA-ARS Meat Animal Research Center found no more stock days were being harvested from their fertilized pastures than from the non-fertilized pasture.

How can that be when the fertilized pastures were clearly more productive? Sometimes, over the course of the grazing season we simply fail to capitalize on the added production even though it’s right there in front of us. In that case, all we’ve done is added more cost to the pasture without gaining a benefit.

There are other times when the value of the animal product is not great enough to pay for the cost of the N investment. With the record-high cattle prices of 2014, the economics of N fertilization may have looked a little better, but for most of the last 20 to 30 years, N-fertilization has not been a paying proposition for most cow-calf producers.

What about fertilizing with other nutrients such as lime or phosphorous or micronutrients? That response is very site-dependent and also comes back to the relative value of animal product and cost of fertilization.

Most legumes require higher levels of P, K and several micronutrients than do grasses. If you want to replace commercial N fertilizer with legumes as your primary N source, you will likely need to beef up some other aspects of your fertility program.

One positive aspect of applying nutrients other than N to the soil is most of these other minerals tend to stick around the pasture longer than N does.

Because of the potential for N to be lost from the soil as gas or leached out of the root zone as nitrates, a pound of N applied on your farm this spring is unlikely to still be working on your farm by the end of the growing season. A molecule of phosphorus applied this spring will still be recycling through your pasture several years from now.

Building additional subdivision fences to help with grazing management is one of the most overlooked pasture improvement strategies but generally has a very high rate of return on investment.

Because subdividing pastures allows you to better control the length of time any pasture is exposed to livestock grazing, all of the other pasture improvements mentioned above can be more effectively implemented.

Legume interseeding is consistently more successful when appropriate grazing pressure can be applied to the existing grass stand to ensure establishment and persistence. Concentrated cattle hoof action can be used to help incorporate seed.

Greater benefit is derived from N fertilizer applications because time-controlled grazing results in increased seasonal utilization rate or harvest efficiency. Grazing at higher stock density results in more uniform manure distribution, so less purchased fertilizer input is needed annually.

Sometimes we may also need to add more stock water availability to get grazing distribution where we want it to be. Developing stock water generally costs more per acre than building subdivision fences, so careful planning is needed to keep the project within a budget level appropriate for your scale and type of operation.

These are some of the practices that come to mind when we start talking about pasture improvement projects, but some have a much higher payback potential than others.

Sitting in a tractor dragging a harrow around your pastures may provide plenty of time for meditation, but the same time invested in fence construction or pulling a no-till drill while interseeding legumes would probably be a much better use of your time and efforts.  FG

PHOTOS
PHOTO 1: Even though farmers and ranchers have been dragging pastures for generations, there is very little evidence to support any economic benefit from the practice. Photo by Dawn Gerrish.

PHOTO 2:Interseeding legumes can translate to big dollars in the form of soil nitrogen credits and increased nutritional grazing value. Photo by Jim Gerrish.
 
Jim Gerrish
  • Jim Gerrish
  • American GrazingLands Services LLC

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