Setting benchmarks for soil quality
What is soil quality?
What impact do specific farming practices have on soil quality?
Are we improving soil quality on our farms and ranches?
What is the difference in soil quality on native pasture and crop ground?
These are a few of the questions that DeAnn Presley and Lyle Frees are attempting to answer with the soil quality study they began last November. Presley is an assistant professor of environmental soil science at Kansas State University and Frees is a USDA-NRCS water quality specialist.
Presley and Frees began taking soil quality measurements on farms across Kansas last November. Eventually, they would like to collect data from as many different regions of the state as possible and from as many different soil types as possible.
"Our purpose for doing these tests is to quantify what is soil quality and add quantitative value to it," Frees said.
Presley began talking about soil quality at field days shortly after she began working at K-State in 2007. After these field days, farmers would come up to her and ask how they could collect these measurements on their farm or, better yet, would Presley come out and collect the soil quality measurements?
"All the tools we use are extremely simple tools," Presley said.
They use the Soil Quality Test Kit, developed by the U.S. Department of Agriculture, Agricultural Research Service, the Natural Resources Conservation Service, and the Soil Quality Institute. The kit describes procedures for 12 on-farm tests, includes an interpretive section for each test, data recording sheets, and a section on how to build your own kit. The Soil Quality Test Kit is divided into two sections, a section on test procedures and a background and interpretive guide. Presley normally does five or six of the measurements in the test kit that focus on the main characteristics.
"Soil quality is nebulous but there are ranges on these properties that we feel are desirable," Presley said.
Physical properties include aggregate stability and soil tilth. Aggregate stability is an indicator of how well water will infiltrate the soil. Soil tilth can show how easy it is to plant into a particular soil.
"We don't put a dollar value on these but, if we did, they would be priceless," Presley said.
In the biological portion of their testing, Presley and Frees do an earthworm count. Frees said it appears to him that you can get some indication of trends from earthworms. Farmers in Iowa and Illinois have been talking about this for some time.
"What we saw this spring, using rangeland comparison sites, is that if you start to see some earthworm activity in cropland, that is a positive indicator that things are moving in the right direction," Frees said.
Earthworms are something producers and researchers can see and actually count. Earthworms are a visual indicator of nutrient cycling of nitrogen, phosphorus and all of the microbial activity that goes on in the soil--activity that results in plant health and soil health.
"We can take soil tests to determine what the level of nitrogen is or what the organic matter is, but it is difficult to track the biological health of soil," Frees said. "This is one of the ways we can track that element."
Frees said it was a real eye-opener to see a particular soil, like Harney, in a pasture and then move over into a cropland and see the difference. They counted 15 to 20 worms in the top cubic foot of soil in the pasture; then, a few feet away in the cropland, there was no activity.
When they are doing these soil quality assessments, Presley and Frees try to compare like soil type to like soil type for what is common on that farm, in the area and in the region, so there is more application to more producers than just that one. They use rangeland or pasture as the reference site. Then they compare samples from cropland to the reference site to see what activity is taking place.
Presley said it takes about two days to complete the assessment on the farm, plus time in the lab. Since last November, they have done three on-farm assessments. This is an unfunded research project, so Presley and Frees work this in around their other work assignments. Presley said her goal is to do six on-farm assessments a year. She is also doing similar assessments on K-State research farms and fields around the state.
Kevin Wiltse, who farms 20 miles west of Great Bend, invited Presley and Frees out to his farm after talking with Frees about the work they were doing. On his farm, they took samples from native rangeland that had never been tilled, fields that had been no-till farmed for 10 to 11 years, and fields that had been in no-till for over 20 years. Wiltse said they were particularly interested in his farm because he has begun using cover crops recently.
"They were looking at whether or not we can accelerate the improvement in soil quality through the use of cover crops," Wiltse said.
Two years ago, Wiltse used cover crops on just a few acres but last year he expanded the practice on his farm. Wiltse uses a cover crop after wheat and before the following spring crop, which is usually milo. He used sun hemp as a cover crop on a few fields and a cool-season mix of forage radish, winter canola, turnips and hairy vetch on other fields.
"Soil quality improvement will not happen in one year, even with cover crops, but it is the general consensus that we can improve soil quality with cover crops," Wiltse said. "It will just take some time to put numbers to it."
Presley said they want to find out why farmers do what they do and get that information out to other farmers. Farmers see themselves as stewards of the land rather than environmentalists. They want to manage the land to improve or maintain the property so they can pass it along to their children, if they want to farm someday.
Frees said their work does carry over to surrounding states and has regional applications. Frees said soil types don't honor state boundaries.
"We are trying to go out and gather these data sets with a purpose," Presley said. "The more data we have from more people in different soil types and in different production methods the better. We are always looking for more places to take samples."
There is no time limit for this unfunded research effort. In fact, Presley and Frees see this as their life's work, collecting vital data about soil quality. They are establishing a benchmark so that years from now we can look back and see if we are, in fact, improving soil quality. What difference, if any, has no-till or cover made to soil quality?
Doug Rich can be reached by phone at 785-749-5304 or by e-mail at firstname.lastname@example.org.
Editors note: You can contact DeAnn Presley at 785-532-1218 or Lyle Frees at 785-823-4540 if you are interested in doing a soil quality assessment on your farm.