Pastures tend to segregate nutrients
I remember helping sort cattle when I was growing up, and it always seemed to me the nature of a cow was to do the exact opposite of what I was trying to get it to do. I think that is why I ended up focusing on equipment and plant nutrition in my studies at college. These things might not pay attention to me either but at least I didn’t feel like I was being deliberately disobeyed.
As precision agronomy manager for MFA, I see maps from a lot of pastures that have been grid sampled through our Nutri-Track program. I think grazing animals have the same mentality as those cattle I tried to sort when they “fertilize” a field; it’s anywhere but where you want it. Of all the fields I look at, without a doubt, pastures consistently have the most variable fertility. Near shade, water, or feeding areas nutrient levels are usually high—right off the charts. Meanwhile, areas have the best potential at forage production tend to be deficient in basic soil nutrients. For this reason, I think pasture ground may have the highest opportunity for return on investment for precision nutrient application.
There are several strategies we can use to help minimize uneven redistribution of nutrients in pastures. If you are not already, I would recommend implementing a rotational grazing program that will force your livestock to move more often and better distribute manure. During the winter, rotate supplemental feeding areas as often as possible. Both of these practices will lead to a more even grazing and “fertilizing” pattern. They also move livestock to parts of the pasture they wouldn’t otherwise visit and should help reduce plant damage from heavy traffic. It is also a good idea to drag your pastures annually to break up and distribute manure.
While these practices will help mitigate the problem of uneven nutrient distribution, we have an invaluable tool in the Nutri-Track program to help us manage pasture fertility effectively. By taking samples every 2.5 acres, we can identify the distribution of nutrients and fertilize accordingly.
As is the case with other fields in the Nutri-Track program, the first thing we want to do is correct the soil pH. The pH of the soil plays a critical role in availability of nutrients and overall performance of the forage crop. This is doubly true if your pasture has legumes or you are planning to seed legumes. In fact, the MU Extension guide G4651 “Renovating Grass Sods With Legumes” states that legumes should not be seeded into fields with a pH value that is less than 6. As a bonus, it has been shown time after time that the cost of the program is paid for through the savings in lime application versus a flat-rate program.
All too often, phosphorus and potassium fertility are an overlooked component of maintaining quality pastures. Nitrogen is important and does increase grass yield, but if phosphorous and potassium are ignored too long, you will see diminishing returns from nitrogen applications. If the soil is low in these nutrients, your pasture will never reach full yield potential regardless of how much nitrogen is applied.
Balanced fertility is also an important part of stand persistence. Healthy plants are better able to with stand traffic and tough conditions, whether due to a drought or a severe winter. Maintaining a healthy stand of forage also means less room for weed pressure which may help reduce chemical costs.
In more recent times I have seen many cattleman sort and move their cattle with apparent ease. I think it’s because they know their cows and what they want, that they are able to move them so effortlessly. Similarly, we can use the Nutri-Track program to identify and understand our herd’s nutrient placement strategy and rebalance the fertility throughout our pastures. The payoff for proper soil pH and nutrient levels is a healthy pasture. They’re good to look at, but more importantly, you’ll be providing higher quality and quantities of forage for your herd.
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