Absolutely NOT. That is equivalent to reducing feed purchases by cutting back on feeding grain, regardless of how they are milking. It is distressing to see farms fertilizing by best guess, and then shorting their profitability some where else because “enough” money was spent on fertilizer. If you cannot get your whole farm sampled, concentrate on corn fields and fields that are going to be seeded. These have the earliest fertilizer additions. Hay fields can be sampled after first cutting and the top dressing applied after second cutting.
The biggest regulator of the return on your fertilizer investment is to raise the pH to 6.2 for corn or 7.0 for legumes. This is where expensive fertilizer is most available and the plant growth can make the most use of it. As the pH drops, fertilizer efficiency drops 30 – 50% in producing crop yield.
Correct pH soil is a BASIC MANAGEMENT PRINCIPLE for any manager who has any desire to run a profitable farm. A few years back I worked with a top managed farm that started a complete farm soil testing program. He discovered to his surprise, he had alfalfa fields that were at a pH too low to ever grow corn well! Ironically, he was putting too much fertilizer on high testing manured corn fields, to the point of hurting plant growth by tying up minor elements. What he saved on fertilizer more than paid for the needed Time IN ONE YEAR! Since then, several more farms have gone on to whole farm soil testing and have had the same results: decreased fertilizer bills and an increased need for corrective liming, and less expensive forage cost for the yield achieved. As the price of fertilizer continues to go up, the investment in this critical part of your crop production demands the highest return on each dollar invested. Unfortunately as more farms are finding the benefit of comprehensive soil testing and recommendations, we were learning that they were severely handicapped in forage profit for several years for having low pH. Fields of 5.4 – 5.8 are common, especially on rented ground. They tried to save on fertilizer by no liming. At these pH levels, as the chart below shows, you are throwing away a third of your fertilizer impact. Even at pH 6.0, nearly 20% (one bag in five) is lost due to the acid soil’s effect on availability. In this era of high prices, correcting the pH FIRST and then adding what fertilizer the checkbook will allow you, is the way to maximize the return in your crop.
~ Excerpted from Thomas Kilcer’s “Crop Soil news, Nov. 2019