Invest in a Tissue Test
Leaving no yield in the field is always an important goal, but it’s especially important when commodity prices are as strong as they are. It literally pays to harvest more tonnage! In-season testing will verify whether your growing plants’ nutritional needs are all met, which helps your alfalfa and corn silage crops reach their full potential.
It’s more challenging to determine actual alfalfa and corn silage yield and correlate yield to plant nutrient removal than it is to do so for corn or soybeans. A more accurate way to determine soil and plant needs for alfalfa is in-season soil sampling combined with plant tissue sampling.
The chart below provides examples of tissue sampling methods. You will find a link to full descriptions here: www.dairylandlabs.com/agronomy-services/plant-tissues. I like to add this layer of fidelity on at least a few acres as it gives me a sense that I have done my best. The lab results you get will indicate if a nutrient is still lacking and the amount to supplement. NOTE: It’s helpful to provide a soil sample (at least 10 cores) from area of tissue sample.
For Best Results
Modern alfalfa plant genetics have a lot of capacity to yield, but plant nutrition is key to achieving those top yields. Potash, phosphorus, boron and sulfur are key nutrients. The top yield-driving nutrient is potassium. Split-applying potassium to alfalfa tends to provide the best results.
Alfalfa will remove 50 to 55 pounds of potassium per dry matter (DM) ton, so a total of 300 pounds may be removed per acre in one season. A split application of 150 pounds of potash per acre will help avoid any leaching potential. NOTE: Alfalfa consumes more potash than it needs, a condition called luxury consumption. If you apply more than 200 pounds of potash per acre in one application, there is a high potential for luxury consumption. The plant can only use a certain amount for yield, but an alfalfa plant will continue to consume as much potash as it can. Potash will increase plant tissue concentrations. As a result, it can cause negative animal health issues when the forage is fed.
To maintain maximum animal health, as well as plant health, it’s important to study both data from your field and from your alfalfa plants. Mosaic® fertilizer has a great nutrient removal chart, which correlates expected yield with critical nutrient removal rates.
Maintaining peak nutrition keeps alfalfa plants healthier, so they live longer. More live plants when you plan to rotate to corn can provide up to 100 pounds of nitrogen credit or even greater. It pays to keep alfalfa happy!