N soil test to save dollars
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
Soil and climatic conditions have varied greatly so far this growing season. Rainfall and soil temperatures have been variable. Over the last few days with high temperatures and plenty of moisture, crops have grown tremendously. Soil microorganisms have also become much more active in converting organic nitrogen into plant available ammonium and nitrate N. Where cover crops, compost or even crop residues have been incorporated into the soil, considerable nitrogen may become available. Nitrogen provided by one of these sources or even soil organic matter is nitrogen that does not need to be provided by purchased nitrogen.
Soil sampling is the only way to know for sure how much plant available nitrogen is becoming available in the soil. Collect 15 to 20 soil cores to a depth of 12 inches from the area of interest not to exceed 20 acres. Dry the sample as quickly as possible before sending the sample to the soil test lab. Also, keep the samples cool as possible. If the soil will be delivered directly to the soil test lab, then drying is not necessary. At a value of 40 to 50 cents or more for each pound of nitrogen, finding out that the soil already contains 30, 40, 50 or more pounds per acre can have a significant financial impact.