Professor Richard Cruse speaks on Iowa’s topsoil


Richard Cruse is an Agronomy professor at Iowa State University. His research focuses on soil and crop management. One of his most recent projects involved leading a research team that created a system to more realistically estimate the amount of soil erosion occurring in Iowa. Cruse talked with Iowa Environmental Focus about this project, and about the importance of preserving Iowa’s topsoil.

Why Iowa needs its topsoil:

Topsoil is a basis for our economy, the basis for international trade and the basis for food production worldwide. The science related to soil erosion is that when soil erosion proceeds, soil’s productivity potential drops. That occurs in Iowa, and it occurs basically anywhere in the world. As we look to the future there is no question that our population growth is going to continue and the demand is going to increase. To meet that demand we’re going to have to increase productivity, and we’re going to have to do it in a way in which this absolutely necessary resource is maintained. These were pretty much soft words in the 60’s, 70’s, 80’s and 90’s because we had grain stored on the countryside. The amount of stored material versus what we needed was in excess. We’re moving into an era of increasingly frequent shortages.

Cruse’s soil erosion estimation project:

Our most recent contribution involves estimating soil erosion rate daily in the state of Iowa for every township. This is a bit different than work that has been done in the past in that we’re using remotely sensed information. We’re using radar estimates of rainfall; we’re using the most current soil erosion technology available; we’re using various soil databases; and we’re using [digital elevation models] that we’ve used in the past to get our slope values. We’re combining a variety of technologies that allow us to estimate what’s happening daily on a spatial basis. The other tools that we’ve had involved giving an average estimate of erosion across an area while assuming average normal weather conditions. But we know that the weather and rainstorms aren’t average on a daily basis. Take 2008 for example, if we used our traditional methodology we would get a much different idea about what erosion occurred in Iowa, especially spatially. This is because we can’t take into account the concentration of storms that we saw in northeast Iowa. With the newer technology we’re able to do that, and we’re getting a much better spatial resolution of what’s really happening.

Why he helped create the Iowa Daily Erosion Project, which displays the data collected from the soil erosion estimates:

There are two motivations [for the Iowa Daily Erosion project]. One is that so it’s available to the public, and the other one is to raise awareness. People hear the term “soil erosion” a bit differently when they can see exactly what is happening in their location in relationship to another location. We also have a certain amount of funds available through different programs, and this gives us an idea of where those funds might best be targeted. We see areas that are consistently being damaged or degraded – those are the areas that we think we are better off using resources to sew the wound.

The next step in estimating soil erosion:

The current technology that we use relies on management data that was obtained several years ago. That’s the best data that we have – we’re not operating well in real time. Our erosion technology estimates soil erosion on single hill slopes in the township. The next steps are to make use of lidar, which will give us better slope resolution; use better rainfall resolution from the [high-resolution rainfall observatory] at the University of Iowa; and use an improved version of our soil erosion modeling which will allow us to estimate soil erosion and soil loss in small water sheds. So, we’ll go from hill slope soil erosion estimates and making a broad paintbrush statement about a township to making actual estimates of soil erosion in watersheds.         

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