Learn More About Your Soil Fertility

Carrie Laboski, Dept. of Soil Science

Nitrogen on Corn

Are you interested in learning how the maximum return to nitrogen (MRTN) corn N rate guidelines work on your farm? If so, your County Extension Agent can help you conduct on-farm research that will tell you how much N was needed in your corn field in 2007. In addition to learning more about your soil’s ability to supply N, the data will be included in UW’s corn N response database. This is the database that we use when updating N rate guidelines that are published in UWEX A2809 Nutrient application guidelines for field, vegetable, and fruit crops in Wisconsin. Adding more on-farm data from a wide range of soil types makes our database more representative of soils and management practices that occur in the real world.

Briefly, the study involves applying several rates of N in strips across a field several times. A few preplant soil samples are required. Other than varying N rates, all other production practices should be standard for your farm. Yield measurements can be made with either weigh wagons, a calibrated yield monitor, or by hand. Data reported back to me will be statistically analyzed and the results/interpretations provided to you. Contact you County Extension Agent if you are interested in participating.

If you are a consultant and would like to test MRTN with some of your clients, see the following website for protocols and an Excel file to assist with data collection and organization: http://www.soils.wisc.edu/extension/onfarmdemo/

Potassium

Over the last few years there have been many reports of soil test K levels dropping dramatically. I am seeking growers, consultants, and County Agents that are interested in conducting on-farm research with potassium on corn, soybean, or alfalfa. The main goals of the on-farm work are to: 1) measure yield response to applied K; and 2) evaluate how often a yield response to K fertilizer occurs at existing soil test levels. Optional measurements can be taken to meet two additional goals: 3) verify K₂O removal values; and 4) assess changes in soil test K during the growing season. The results from this work will complement a more detailed research project that I have and will be very useful in assessing the validity of UW K recommendations outlined in UWEX A2809.

The on-farm research involves two treatments: potash applied vs no potash applied. These will be in replicated field strips. Some soil sampling will be involved and yield measurements will be taken. Data reported back to me will be statistically analyzed and the results/interpretations provided to you. See the same website listed previously for details on the protocol and data collection file. Please contact me with any questions. My phone and email are: 608-263-2795, laboski@wisc.edu