Redefining Ideal Soil Fertility

June 1, 2015 Ohio Soybean Council

In 1995 The Ohio State University, in collaboration with Michigan State University and Purdue University, published fertility recommendations for field crops in the tristate area. Over the last 20 years, a lot of things have changed; the fertility recommendations have not.

The issue at hand is that farmers are working off of standards that were set 20 years ago while they are able to utilize technology that is now advancing every year. New varieties with advanced traits may not require the same amount of certain elements. Looking at a decline in commodity prices and an increase in inputs, a relatively small adjustment could provide a little extra boost to farmers with tight profit margins in addition to allowing for better nutrient management practices.

“Recent events in Ohio have brought the issue of water quality to the forefront and put producers under a lot of pressure to update to a better nutrient management practices,” said Gretchen Mossbarger, Chair of OSC’s research committee. “Research on soil fertility is a key component to allow growers as well as fertilizer applicators to be more precise and mindful in their use of nutrients.”

As researchers such as Steve Culman, a soil scientist from Ohio State, take to the field to collect data, farmer participation is in high demand.

“We are relying on farmer cooperation; if we don’t have a lot of buy in from the agricultural community the success of this project is going to be limited,” said Culman. “What we need the most help with is trying to capture a wide diversity of soils, different management practices and their interactions. We’re trying to get robust information by going on farm and asking producers to put out strip trials where we can measure the response to fertilizer or the lack of fertilizer.”

Some major differences in common practices since 1995 and today include the popularity of no-till, differences in row spacing and roundup ready soybeans. As researchers look to revalidate the recommendations, they’re focusing on two major nutrients for soybeans which are phosphorous and potassium.

“We often hear producers saying the tristate recs aren’t relevant because they have really high yielding fields, but we want to test that; and we want to test low fertility fields,” said Culman. “We often have a hard time finding producers who want to work with us when their soils are below the critical level where we would expect a response to fertilizer. We are looking for soils that are low in phosphorous or potassium.”