• By Adam Probst, Extension Agent

Agriculture & Natural Resources: Yield goals could cost you this year

Source: Dr. Chad Lee; UK Grain Crops Specialist While we are thawing out and getting soil tests done this spring, I wanted to remind you of a few basic principles that we use in developing our soil test recommendations. The following from Dr. Chad Lee does a good job of discussing the “why” our recommendations are what they are.

Recently, I worked with a small group of farmers who were interested in trimming costs, but not their yield. They provided their soil test values, historical yields, crop history, and intended production practices for this year. Those producers reported that they were applying $124 per acre more for fertilizer than what was recommended by the University of Kentucky. Even if we factored in enough fertilizer for the following soybean crop, they were spending about $100 per acre more. They were using yield goals to make their fertilizer decisions. Producers enjoy farming based on yield goals. Yield goals are positive thinking. They are a challenge to the producer to try to reach higher yields. Annual budgets have yield goals. Loans require an estimate of income which requires a projected yield. Yield goals are easy to market and easy to understand. Yield goals also could cost you a lot of money.

The University of Kentucky publishes AGR-1 Lime and Nutrient Recommendations every two years. These recommendations are based on decades of research on soil test values, fertilizer rates, and yields in Kentucky. The rates in AGR-1 are based off of these research results.

Many yield goal strategies include fertilizer rates to meet the expected crop removal rate. Often, those crop removal rates are much higher than the agronomic response of fertilizer reported in AGR-1.

The farmers in that small group were applying more phosphorus, potassium and zinc than what AGR-1 recommends based on soil test values. While these rates were high, the phosphorus, potassium and zinc were not high enough to be an environmental risk. The additional phosphorus, potassium and zinc should increase soil test values and a portion of each should be available for subsequent crops.

As long as these fields are managed by the same growers in subsequent years, they can recoup part of their investment on the additional fertilizer. With even tighter margins this year, the only real loss these producers face is the additional expense on fertilizer that likely will not increase yields a single bushel.

While a yield goal method tends to recommend more fertilizer on fields that soil test in the moderate to high range, the yield goal method could suggest less fertilizer on fields that soil test low or very low. In these low-testing fields, AGR-1 is attempting to increase soil test values in addition to providing enough nutrients for the crops. So, a yield goal method likely over-fertilizes fields that soil test high and possibly under-fertilizes on fields that soil test low. Again, yield goals are fun to talk about and are easy to understand. They may not be the most economical approach in a year like this. If we cannot convince you to step away from the yield goal approach for this year, then we will suggest an adjustment to your yield goal. For 2018, consider using an Olympic average as your yield goal instead of the maximum. If you follow AGR-1 for fertilizer and we get a good season, then you have a great chance of beating your Olympic average. For more information or to obtain a copy of AGR-1, contact the Woodford County Cooperative Extension Service at 873-4601.

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