View from my Windshield: Observations of soil erosion across Iowa

Post written by Hanna Bates, Program Assistant at the Iowa Water Center

For the past couple of weeks, I have been on the road across Iowa. These trips vary in their purpose, but one thing that remains the same is the evident erosion in the fields along my travels. Regardless of where I am – whether it is in the Loess Hills visiting family or in the Des Moines Lobe for a meeting – spring rains have revealed that there are deep cuts in the bare brown soils where lush, even soils used to be.

Cruse et al. (2016) writes:

“Topsoil thinning is closely linked to loss of crop production potential. Typical statewide average erosion rates have only a minor impact on crop yields in the subsequent year. However, cumulative effects are far more significant and contribute to a loss of state revenue that becomes much more important as time progresses.”

The simple fact is that without soil there would be no life. In Iowa, we have high quality soils that, along with some good science and great farmers, enable us to be the top producers in corn, hog, and egg production. This leads to the question: What may be the ultimate cost of this productivity?

Cruse et al. (2016) conducted a study to determine the effects of erosion on commodity yields and to gauge the future impacts on the agricultural economy in Iowa. Researchers studied seven farm sites in Iowa with cropping history and available yield maps. The Daily Erosion Project was used to estimate crop yield impact on soil depth from 2007-2014. The average state loss across those years was 5.7 tons of soil per acre per year. “Assuming a 2.2 bushel per acre corn yield loss across 14 million acres in a given year and a corn price of $4.00/bu, the next year’s crop production loss would equate to approximately $4.3 million total across this land area” (Cruse et al. 2016). There are informational resources and federal programs available for soil conservation practices, but with a short-term economic market system, there is little motivation to participate.

Cruse et al. (2016) writes:

“Short-term minor yield impacts on a per acre basis create little incentive for investing in short-term soil conservation strategies available for many farmland renters. However, as the cumulative effect compounds the economic effect over time, landowners that have longer term planning horizons are much better positioned to recover their financial investments in soil conservation practices.”

To put is succinctly, a loss of soil leads to a loss of productivity, which leads to a financial loss for the state. The impacts of the above findings on decision-making out in the field may be significant given the short-term mindset of our commodity market. Making present-day investments to maintain soils may pay off in the end when compared to short-term commodity gains from year-to-year. Other research has revealed that there is hardly a piece of land in Iowa that is exempt from the problem of erosion. According to Cruse et. al. (2006), soil erosion affects everyone although it is spatially and temporally variable. With 55% of Iowa farmland leased rather than owner controlled (Duffy et al. 2013), an investment in soil saving practices will require candid conversations and real partnerships between a tenant and landowner.

Overall, the first step in making a change is being knowledgeable about your surroundings. Next time you are on the road, look out in the field and really see where you are travelling. Then, compare that to what the data shows on the Daily Erosion Project. You may be surprised about what you learn.

References

Cruse, R., D. Flanagan, J. Frankenberger, B. Gelder, D. Herzmann, D. James, W. Krajewski, Kraszewski, J. Laflen, J. Opsomer, and D. Todey. 2006. Daily estimates of rainfall, water runoff, and soil erosion in Iowa. Journal of Soil and Water Conservation. 61(4): 191-199.

Cruse, Richard M., Mack Shelley, C. Lee Burras, John Tyndall, and Melissa Miller. 2016. Economic impacts of soil erosion in Iowa. The Leopold Center for Sustainable Agriculture. Competitive Grant Report E2014-17.

Duffy, Michael, William Edwards, and Ann Johanns. 2013. Survey of Iowa Leasing Practices, 2012. Iowa State University Extension & Outreach. File C2-15.

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