This summer, MFA will surpass 260,000 acres in its Nutri-Track program. Because Nutri-Track is typically based on a four-year sampling cycle, and given the pace of sign-ups, we hope to reach more than a million acres with the Nutri-Track sampling program in the next couple years. As you might guess, the majority of these acres are in corn, soybean and sometimes wheat rotation. However, one of the fastest growing segments of intensive soil sampling is pasture and hay ground.
There are good reasons for this surge in interest for site-specific fertility management on forages. Among them are higher cattle prices; increased scrutiny of fertilizer application and its environmental impact; and increased availability of variable-rate application equipment.
There is plenty to gain from precision nutrient management on hay and pasture land. Regardless of whether you grow corn or fescue, plants need balanced amounts of essential nutrients for optimum performance. Whether it’s brome or soybeans planted in a field, nutrients won’t be as readily available unless the pH is at proper levels. And for more intensively managed forage crops like alfalfa, money saved from variable-rate lime applications prior to seeding will offset the cost of grid sampling just as it will prior to row crops. Soil tests need to be taken in a manner that allows you to check nutrient levels, the soil pH, and the variability in the field. Whether your crop of choice is grain or grass, the basics of soil fertility stay the same.
Nutrient and pH variability change with many field-level factors, man-made and otherwise. In row crops, nutrients returned to the soil in the form of stover are usually spread through the combine uniformly and lands not far from where they were removed. In pastures, a major factor in nutrient variability comes from livestock. The nutrients cattle return to the soil via manure will be returned in places where cattle spend the most time. Those areas could be near feed bunks, ponds or waterers, mineral feeders or shade trees. A steer or heifer puts little thought into dispersing nutrients evenly, but with grid sampling, you can figure out the scope and severity of this disproportionate dispersal of nutrients.
Once you have accounted for the existing nutrients available to pasture and forage crops, variable-rate application of nutrients allows you to avoid over-fertilizing areas that cattle have already fertilized. Just as importantly, you can add the right amount of nutrients to optimize forage yield throughout the pasture.
Hay fields may not have cattle redistributing nutrients, but they come with challenges of their own. First, if you compare nutrient removal of 1 ton of cool-season grass hay compared to 67 cow-days on pasture, you will see that the only real equivalence is the amount of nitrogen required. For hay, phosphorous removal is doubled and potassium removal is tripled.
Moving harvested hay from hay fields to feed in a pasture is another form of nutrient redistribution you need to think about. The math gets complicated. Grid sampling helps you track these nutrients and fertilize accordingly.
Nutri-Track and variable-rate fertility are all about accuracy and efficiency. The program helps you put inputs where they are needed and pull back where they are not. These practices will not only save input costs on lime and more evenly distribute nutrients, but they can lead to increased productivity—you can increase stocking rates or grow more hay from the same acres. That’s one low-cost investment that can bring big returns on your beef operation.