If you were not able to soil sample fields for nutrients last fall following harvest; it’s not too late to sample fields this spring, especially if you have some you are unsure of their nutrient status. It is important to know what your next crop needs and apply fertilizers accordingly. In 2020 there were less problems of nitrogen deficient corn fields compared to 2019 when there were a number of fields in southeast Nebraska that showed signs of nitrogen deficiencies, with potential for other nutrient deficiencies or imbalances. If you are planting corn on corn, conducting a soil test is very important, especially if it yielded lower than anticipated and/or turned yellow in late summer. Definitely consider soil sampling and testing fields for nutrients, such as phosphorus, potassium, sulfur as well as nitrogen. The erratic weather conditions we experienced the past couple of years resulted in extreme growing conditions in some areas of southeast Nebraska. As we plan for 2021 it is important to use fertilizer wisely and being efficient as possible with the fertilizer that is applied. With the erratic weather patterns and some torrential rains we sometimes have received, there is potential for nutrients to be lost through erosion, leaching or denitrification. Depending upon soybean yields in 2020, you may be able to apply a significant nitrogen credit (at least 40 lbs. of N) for 2021 corn following soybeans. Nutrient deficiencies in soil can also have a significant impact on yields of both corn and soybeans. If you soil sample, you may be able to save on your fertilizer bill for this year. Soil pH can have a real impact on nutrient availability and consequently reduce yields, particularly soybeans. Liming could help improve the availability of nutrients in your fields and help improve yields. This is why soil sampling is important. If you have fields that have not been limed for several years, it may be a good time to sample these fields.
Under irrigation where yields are usually less variable than dryland crops, there is heavy removal of nutrients in the grain that may need to be replaced for this year’s crops. Ideally soil sampling in the fall or winter is better, but there is still time for soil sampling and applying limestone and fertilizer this spring. The UNL publication EC117 “Fertilizer Suggestions for Corn” provides excellent advice for sound fertilizer management and gives you the tools to make sound decisions on fertilizer needs for corn. This publication can be accessed on the web at: http://agronomy.unl.edu/faculty/ferguson/ec117.pdf.
University of Nebraska-Lincoln Extension also has a nitrogen calculator available on the web you can use to calculate nitrogen needs for your corn crop. If you go to this link: http://cropwatch.unl.edu/soils and then click on Corn Nitrogen Recommendations Calculator, you will be able to access this tool.
If you have questions on soil sampling, soil test labs in Nebraska or other questions, feel free to contact me at University of Nebraska Extension-Lincoln in Nemaha County at (402) 274-4755 or your local county Extension office.