Soil Fertility Understand the Basics

Name and Position/Title:       
Joel DeJong, Field Agronomist

Fiscal Year Submitted:

POW Title and Number:
100  Corn and Soybean Production and Protection

Soil Fertility – Understand the Basics

As a field agronomist, I have received lots of questions in recent years from producers who do not understand the basics of soil testing, application rates, and many other items that are needed for understanding soil fertility. Crop yields have increased, but not all fertilizer rates have kept up. Others might not be getting a good return on their fertilizer investment. If a producer grew 200 bushel corn and 50 bushel beans on 250 acres of each last year, they removed over 14 tons of phosphate with your grain, and almost 17 tons of potash. Managing that right can be very valuable, and increased costs make this an issue of greater importance. Some of these crop producers should become better consumers who make these fertilizer decisions.

I worked with John Sawyer and Antonio Mallarino to develop a workshop to teach the basics of soil fertility for crop producers. John co-taught the workshop with me. This one day workshop was designed to look closely at the basics of P and K in crop production, how recommendations are developed, calculate the rates of application, talk about the difference between pounds and units, and discuss different management theories. We then turned to N management, forms, and how loss occurs. Also, N management tools were discussed. Reviewing soil lime needs followed, with a review of research results to lime applications, and a discussion and practice problems on ECCE calculations for different forms of lime. At the end of the day we spent a little time on micronutrient responses in Iowa. 41 paid participants attended this workshop, which had a maximum enrollment of 40 advertised. Six remained on the waiting list, so this workshop will likely be repeated in the future.

Evaluations were completed by 38 participants. All agreed that the ideas presented provided them with new knowledge that they intend to apply on their operation in the future. They all also agreed that their motivation level to use this information is very high, and that the cost to attend ($75/participant) was worth it for all participants except one.


100  Corn and Soybean Production and Protection


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