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Building pasture nutrient needs on your farm

William T. Halleran for Progressive Forage Published on 28 February 2017
Building your soil for future production is of greater value over the long haul

Soil makes up the essence of your farm. You are investing your time and money – you own it, you rent it, you operate it – so how do you best manage it for returned profit?

Whether it is crop production such as corn, beans, wheat or livestock production – cattle, hogs or sheep – everyone knows if you don’t feed it a “well-balanced diet,” it will not yield, produce or gain.

Unfortunately, most farm pastures (which should be thought of as crops) are often neglected – some more than others. That’s not to say all producers are neglecting their forage needs, but the question remains, “Are you doing your best to maintain soil fertility while maximizing potential for outputs and/or profitability?”

After all, the more grass produced, the more cattle you can run on the same number of acres over a longer period of time.

But fertilizer is not cheap. I get it … but neither is feed. Building your soil for future production is of greater value over the long haul than many think. If you are soil testing, you are at least thinking about this. Even if you are only renting a neighbor’s farm, fertility will help you in the future.

And by the way, if you are fertilizing for plant growth, don’t forget that weeds are plants too, and they use the high-dollar fertility as well. Do not lose valuable fertility to weeds; eliminate them.

Not all farms are the same, and no two farms are alike when it comes to soil type and its ability to produce, so what do you really know about your soil conditions, and what do you look for in a test? Some farm ground is so far gone it will never pay to fertilize it and that is a decision you, the producer, must make. However, many acres of marginal ground are being neglected to the point that they too will become too expensive to correct.

Continuing to rape the ground year after year and not replacing nutrients or building it back will cost you more money in the long run than you think.

When I look at a soil test, I look at the following items:

pH (Calcium) – This controls the flow of nutrients available in the soil to the plant. Soil fertility is soil chemistry. But don’t panic – this is not rocket science. If the “valve” is only half open, then it is restricting the nutrient flow, and plants don’t feed as well as they could, thus lowering production and profitability. By meeting the needs of the plant’s pH range (opening the flow valve, if you please), you will get the best bang for the buck on nutrient flow currently available in your soil.

Remember, it takes time for the lime to get into the soil, so it’s important to apply lime at least three to six months before you can expect to see results. If fertilizer finances are limited, lime first. Do not skip this, as it will affect how the rest of the fertilizers work when you apply them as well. Lime is the gatekeeper. Calculate your needs based on the suggested limestone in the effective neutralizing material (ENM) rating.

If you are around a half ton or less per acre, it may not be cost effective to add lime, but extra lime will not go to waste – I promise you. If you take soil tests every three to four years and apply lime only once in that time period, a little extra will not hurt.

In the Ozark region, soil pH should be in the ranges listed in Table 1.

Ozark region, soil pH should be within these ranges

Phosphorus – Although different crops require different amounts of fertility based on plant type and yield goals, I am looking for a balanced soil – one ready to go to work as soon as you apply and build fertility for the future. This seems to be the mineral most often short in most of the soil tests I review.

It will limit production even though you pour on the nitrogen. (And, by the way, the more nitrogen you put on the soil the lower your pH will go over time.)

I am looking for the phosphorus number to be around 40 to 45 pounds per acre. This may seem like overkill, but it’s better to have a little extra available than not enough on those lean years when fertilizer dollars are limited.

If broomsedge seems to be increasing in your hay fields, look here. If you continue to mow, rake and bale hay, as well as remove it from your fields without fertility, you are depleting or mining your minerals at an alarming rate.

Potassium – This, like phosphorus, will limit production if a shortage occurs in the soil. Again, different crops require different amounts of fertility based on plant type and yield goals. Here, I am looking for a potassium (K) number around 200 to 250 pounds per acre. Remember, not all plants are alike, and these are guidelines for you to look for so you can get a feel for where you are now and how you would like to proceed.

Magnesium – Even though magnesium is considered a secondary nutrient, it is still important you meet all nutrient needs for the crop. Keeping this in the medium range on your soil test is a bonus. There are different ways to apply secondary nutrients and micronutrients, but one of the most common ways used for magnesium is with dolomitic limestone; it just comes with the lime from the quarry.

When using University of Missouri Extension soil testing service, you will receive our recommendation for your cropping system not only for this year, but for the next eight years. Yes, this is an eight-year, buildup program based on your requested yield goals.

This level of fertility needs to be applied every year until you retest and get a new recommendation based on your progress. Our goal is to balance your soil for future use as well as meet the production yield goals you have now and in the future.

Remember, if you refuse to feed the soil right, do not expect soil fertility to grow at an acceptable rate that will meet your needs in the future.

Another factor, soon to play a major part in soil fertility, is soil quality. Research in soil compaction, absorption, permeability and nutrient flow are all being researched. These too affect how the nutrients flow in your soil.

Remember, the true definition of soil is “a living, naturally occurring dynamic system at the interface of air and rock. It forms in response to forces of climate and living organisms that act on parent materials in a specific landscape over a period of time.”

We are the keepers of the land. We are responsible for the future generation. How are we going to leave it for them?  end mark

PHOTO: Building your soil for future production is of greater value over the long haul than many think. If you are soil testing, you are at least thinking about this. Photo by Mike Dixon.

William T. Halleran is an agronomy specialist with University of Missouri. Email William T. Halleran