From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335

Fall 1999, No. 3


It’s the end of another play. Our team has scored a few times, but Mother Nature has thrown us a few things we weren’t prepared for – drought in some areas, flooding in others. Even on fields where we gained a lot of yards toward our production goal, yields within the field were variable. Where rainfall was scarce, the low ground did better. Where rainfall was excessive, the higher ground yielded more. It doesn’t take a rocket scientist to recognize the extent of our yield variability this year. As Joe Berry has said, taking a field average, whether yield, nutrient, or some other measurement, assumes that the average value is everywhere in a field when, in fact, it may be nowhere. As with any good strategy, we need to see variability not as something that defeats us, but as something we can use to our advantage. How can we do this with our fertilization? Let’s get in a huddle and think about our next play.

Are you going to play again? This is the first question that we must answer before we go any further. Low crop and livestock prices have been serious hits that have been or will be hard to overcome. They have left many of us with injuries that we will have to play around. If we are going to plant a crop next year, then we have answered our question with a resounding “Yes!” If we have decided to stay in the game, then we need to come ready to play. That means preparation, planning, and a mindset that allows us to play with injuries.

To make the next play count, we need a well-planned strategy. It’s time to think about the plays we have made and see which ones worked and which ones didn’t. One of the fundamentals of the game is that higher yields remove more nutrients from the soil than lower yields. In areas where yields were better than expected, nutrient removal may have been higher than anticipated. This means that soil supplies of phosphorus and potassium could have dipped down to levels that are too low for the next crop. Areas testing medium or below in phosphorus or potassium need to be replenished. If these insufficient levels go undetected, we could end up unknowingly reducing next year’s yields. That could be a game-losing mistake. We need those yields to cover the costs of farming and to put food on the table. In places where yields were below our expectations, fewer nutrients may have been taken off the field than we thought. That means that there may be higher levels of nutrients than we anticipated and next year’s crop may be adequately fed without further phosphorus or potassium inputs. These could be places where we can cut costs without cutting yields.

Soil testing is like good coaching. Many of us are on the fourth down with just a few yards to go. We need a strategy that will give us a good chance of moving the ball to the desired yard marker. Soil testing is like an experienced coach who has been watching the opposition. It can tell us where our run for higher yields is likely to be stopped and where it may find a hole in the defense. By fertilizing lower testing areas, we have a chance of gaining some much needed yards toward higher production levels. For some of us, it may be just what we need to reach first down. For others, it may allow us to make a great run. Without soil testing, we may end up punting rather than reaching first down or running for a touchdown.

Let’s spend as much time as we can in the huddle. Our nutrient program is critical for our success. Do we know all that we should? Can potentially costly mistakes be avoided by better knowledge and planning? There is much more information available than we typically use to manage our nutrients. Soil testing is a good start, but we need to know how to interpret the tests that we take. Factors such as tillage, nutrient stratification, management history, and previous yields are some of the factors that determine which play we’re going to use. Let’s make sure we have a good, scientifically-based plan. Properly interpreted soil tests and appropriate fertilization are well-proven strategies for gaining much needed yards towards the goal of higher production and profitability.


For more information, contact Dr. T. Scott Murrell, Northcentral Director, PPI, 14030 Norway Street, NW, Andover, MN 55304. Phone: (612) 755-3444. E-mail:
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