Agronomists point to the importance of soil testing. Low crop prices amplify those reasons. You can’t afford to have your crops fall short of their yield potential because of lack of nutrients. And you can’t afford to apply more fertilizer than your crops require. Plus, overapplication simply is poor stewardship. A soil analysis will help you develop a prescription fertility program. Penn State Extension provides soil sampling guidelines. And most local Extension offices offer soil sampling kits.
Another spring soil sampling window — although it won’t benefit this year’s crop — opens after the crop is in the ground. Results arrive and allow plenty of time to plan your fall fertilizer program. This allows you to have that plan in place and lock in fertilizer prices during the summer when those prices typically bottom out. You’ll be ready to apply your fertilizer in the fall as soon as the combine leaves the field.
Whether you pull soil samples during the fall or spring, most experts recommend you pick one and try to stick to that schedule. This will help you manage seasonal fluctuations. Potassium, phosphorus and pH tend to change during the growing season. Consider potassium: As the crop grows and matures, uptake lowers the amount available in the soil. Once the grain is harvested, the K in the residue washes back into the soil. The timing of your post-harvest soil sampling can skew the analysis. University of Kentucky Extension offers a publication to help you understand these seasonal fluctuations.
No matter when you pull soil samples, the important point is that you do it. Unless you soil-sample, you’re just guessing. And that’s costing you money.