Researchers with Ohio State University's College of Food, Agricultural, and Environmental Sciences have developed a new tool that allows farmers to easily predict soil organic matter content and can help them make decisions about whether or not to sell crop residue.

The tool can benefit growers by providing information for more timely planting and harvesting, reducing operating costs, increasing farm income and building healthier soils, said Rafiq Islam, the soil, water and bioenergy resources program leader at Ohio State University’s South Centers in Piketon.

Called a soil organic matter calculator, the tool is designed to allow farmers to easily evaluate the impact of selective crop residue removal on the long-term agronomic and environmental integrity of their farm’s soils, he said.

The calculator is also designed to help growers select management practices that conserve or build soil organic matter, said Islam, who holds joint appointments with Ohio State University Extension and the Ohio Agricultural Research and Development Center. OSU Extension, OARDC and South Centers are all part of the college.

“Farmers are aware that soil organic matter is the foundation of sustainable agriculture for enhanced ecosystem services,” Islam said. “How you farm today will affect the amount of soil organic matter content your fields will have in years to come, so it’s important to choose sustainable production practices that sustain soil health and protect long-term productivity.” 

The soil organic matter calculator is a spreadsheet-based tool that consists of three primary worksheets that offer multiple options, including a user guide, data manager, a calculator for prediction of soil organic matter, a test scenario module and printed results, he said.

“The calculations are based on several factors including crop rotation, yields, tillage type, tillage depth, erosion rate, manure applications and cover crops,” Islam said. “The calculator, which uses soil organic matter level at the beginning of the simulation period as the baseline parameter, can predict annual soil organic matter dynamics and parameters for up to 50 years.

“The outputs of the calculator consist of total, active and passive soil organic matter, total nitrogen and change in organic matter over the simulation period. The tool can also help calculate the revenue from residue sales and the amount of carbon emitted as carbon dioxide to the atmosphere or sequestered yearly or over the evaluation period.”

Growers can see a demonstration of the soil organic matter calculator at Ohio State’s Conservation Tillage Conference March 4-5 at the McIntosh Center of Ohio Northern University in Ada. Vinayak Shedekar, a graduate student of the Department of Food, Agricultural and Biological Engineering, will demonstrate the calculator. The full schedule and registration information for the conference can be found at

Islam said the soil organic matter calculator can potentially offer a significant financial benefit for farmers attempting to weigh the potential economic benefits and risks associated with selling crop residue from their farms.

This comes as more growers are considering such a move thanks to the increased demand for crop residues from the biofuels industry.

“As a result, farmers are increasingly interested in assessing the impacts of residue removal on soil quality in conjunction with existing and future management plans,” Islam said. “And while several computer models exist to simulate soil organic matter dynamics, most of them are complex and difficult for farmers to use.”

However, Ohio State’s soil organic matter calculator, he said, is simple, quick, inexpensive, reliable and easy to use.

“The calculator can help farmers in important decision-making and farm planning by providing flexible tools to test various options,” Islam said. “The calculator allows farmers to look at various scenarios individually, such as switching to no-till, planting a cover crop, or removing 50% or 75% of corn residue, and immediately compare the effects on soil health and land value up to 50 years in the future.”

In addition to helping farmers select production practices that help them improve soil organic matter and soil health on their own land, the tool could also help farmers who rent ground, Reeder said.

“It could be useful to farmers who want to help educate their landlords about what they’re doing,” he said.

The soil organic matter calculator is based on a model initially proposed by Robert Lucas, a soil professor at Michigan State University. 

The Corn Marketing Program of Michigan provided grant funding to Ohio State to develop the spreadsheet calculator tool, Islam said.

Initially, the calculator was designed to include only growing conditions and soils in Ohio and Michigan, but researchers are currently working on expanding the tool’s range and prediction capability, Reeder said.

Islam and his co-investigators are also working to add more features to the soil organic matter calculator such as liming and irrigation applications, nitrogen and phosphorus dynamics, soil compaction management, greenhouse gas emissions, and soil health, he said.

More information is available online at Select “SOM Soil Organic Matter Calculator” under the Extension menu.

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