Now You Can Put Numbers to the Costs of Erosion

Two years ago, the Land Stewardship Project released the Cropping Systems Calculator (CSC), a “what-if” tool to examine the costs and returns of two crop rotations. This tool includes scenarios that involve row crops and grazing, and provides important information for farmers as they consider integrating soil building practices into their rotations.

The original Calculator was based on default figures for the Chippewa River watershed in west-central Minnesota. Since the Calculator's initial launch, LSP has periodically released updates that include default financial figures for more geographical locations. We've also made it possible for more crops to be considered as part of the mix. All along, we’ve been thinking about how to show the added value of building soil health into the tool. While using the CSC with farmers, I consistently heard comments that only looking at short-term financials wasn’t showing the long-term economic impacts of soil loss.

"To me, soil erosion has been greatly overlooked when it comes to penciling out the economics of a given farming practice," says LSP staff member Bryan Simon, who farms in west-central Minnesota. "Looking at the exposed clay subsoil on my farm’s hilltops makes me wonder how much productivity and profitability has been lost due to the way this land has been farmed. I think accounting for soil loss helps us get closer to assessing the true costs of production agriculture.”

We are now able to offer a tool to begin looking at the soil health benefits related to diversifying a farm's rotation. By creating a geographic information system (GIS) mapping-based soil erosion calculator, former LSP staff member Steve Ewest was able to create reference maps that enabled a soil erosion calculator to be included in the CSC. Using the Revised Universal Soil Loss Equation (RUSLE) equation, this easy-to-enter data helps users utilize numbers to visualize erosion potential.

By entering the crop rotation, tillage method, slope factors, farm location and planting direction, a farmer can estimate how much soil could be lost from fields annually as a result of water runoff. The user has the option of including the percentage of soil organic matter present in the soil. It should be noted that the result is solely soil erosion by water and doesn’t account for soil built because of practices. Because of this, the result will never be positive or even zero soil loss. For example, you could theoretically be building soil with cover crops, but the CSC will only show how much other practices are costing you in terms of soil erosion. To get a sense of how the Calculator presents soil erosion information, check out this example.

The result of the RUSLE equation is provided as pounds, dump truck loads, and inches. Giving results in multiple forms ensures that there is a measurement that everyone can identify with. The amount of carbon, nitrogen, phosphorus and sulfur a farmer is losing per acre as a result of erosion can also be calculated.

While this Cropping Systems Calculator addition doesn’t fully account for the full positive and negative benefits that result from various farming practices, it is an important step in moving forward the conversation on soil health. Give it a try—we welcome feedback.

Rebecca Wasserman-Olin, who developed the Cropping Systems Calculator, recently departed LSP to pursue a graduate degree in applied economics at Cornell University in New York. Questions and feedback related to the Calculator can be directed toward LSP's George Boody at gboody@landstewardshipproject.org or 612-722-6377.

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