10/31/2020

Extension Notes: Fall Nutrient Applications have Advantages - by Rebecca Konopka Carter County Extension Office

Now is a good time for grain producers to get a jumpstart on next growing season. Applying some nutrients to your ground now is one way for you to do that. 

Fall fertilizer applications have many advantages. They allow you to get a job done that can delay planting if it is put off until spring. The weather tends to be drier during the fall in Kentucky, which means your soil is less likely to get compacted when you make an application. Since most fertilizer purchases occur during the spring, you may get a discount from your fertilizer dealer, if you purchase nutrients during the fall. 

The first thing you need to do is soil test your fields, so you only apply the nutrients your fields need. This saves you time as well as money. You can work with your local extension office to submit soil samples for testing at one of the University of Kentucky’s regional soil testing labs. 

Once you get your soil test results, you can begin to fertilize according to UK recommendations. Potash and phosphorus are the two nutrients that are ideal for fall fertilizer applications in Kentucky. Both react strongly enough with the soil that they remain in the ground and their value is not lost through leaching during Kentucky’s wet winters. Recommended rates of phosphorus and potash should be applied before planting small grains in the fall. If you are a double-crop producer, you will want to include your soybean nutrient needs for potash and phosphorus in the fall wheat nutrient application. 

The University of Kentucky encourages corn and full-season soybean producers to wait until the springtime to apply nitrogen and animal manures. Both run a high risk of leaching from the soil with Kentucky’s typically wet winters. Additionally, nitrogen losses can occur from denitrification and immobilization during the winter. Animal manures are most effective when there is a crop already growing in the field.

If you have planted wheat this fall, only apply enough nitrogen to get the crop off to a good start and encourage tillering, which should not be greater than 40 pounds of nitrogen per acre in the fall. If your wheat crop follows soybeans, tobacco or highly fertilized corn, you may not need a fall application of nitrogen as the wheat should have all the nitrogen it needs to grow. If it is determined that the wheat needs additional nitrogen, remember that most of the common phosphorus fertilizer sources in Kentucky (DAP 18-46-0 and MAP 11-52-0) also contain nitrogen that the wheat can use.

For more information, contact the Carter County office of the University of Kentucky Cooperative Extension Service. Educational programs of the Cooperative Extension Service serve all people regardless of economic or social status and will not discriminate on the basis of race, color, ethnic origin, national origin, creed, religion, political belief, sex, sexual orientation, gender identity, gender expressions, pregnancy, marital status, genetic information, age, veteran status, or physical or mental disability.