A transect survey is an annual survey of cropland to determine the soil erosion rate used to compile statistically accurate data on soil erosion by randomly sampling crop fields throughout the county. |
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One method of controlling soil erosion is conservation tillage, which is the practice of leaving plant residue on the surface of tilled soil. Crop residues that decompose on the surface adds organic matter to the soil. Extra residue on top of the soil surface reduces the impact of raindrops on the soil particles, reducing soil erosion. Residue also roughens the surface of the soil, which lowers the runoff potential. |
The purpose of the survey is three-fold: (1) to evaluate progress achieved in reaching county or statewide goals, (2) to provide information that can be used by individual soil and water conservation districts in establishing priorities for educational or other programs, and (3) to provide accurate data on the adoption of conservation tillage systems by crop for the biannual National Crop Residue Management Survey which is compiled and distributed by the Conservation Technology Information Center (CTIC). This makes the transect survey an ideal tool for assessment as well as measuring progress for locally led conservation. |
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Two or three people conduct the survey. At least one individual needs to be very familiar with tillage systems and estimating residue levels. When conducting the survey, someone will need to be the driver, someone a navigator who marks data collection points on the soil survey map, and someone a data recorder and occasionally someone will need to verify field observations (measuring residue, previous crop, etc.).The team will maintain the same members during the survey so that there is consistency of data and evaluations. |
One of the first steps was the creation of a random Transect survey route for the county. The planned route is on mostly lightly traveled roads in order to avoid traffic problems. Vernon County established 10 routes to adequately cover the county. The transect survey, consisting of the 10 routes, covers 300 to 400 miles and has 650 points. |
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Vernon County began collecting data from the 650 points in 1999, and has continued to revisit those same sites every two years since. This year we are taking GPS points of the data sites so that we have a more exact record of their location. Although using the GPS unit won't save time this year, we expect it to in subsequent years because we can print out the stops on a map which can be read by a navigator. We expect that this will really speeds things up for subsequent years. |
Information collected on each site includes present and previous crop history, type of tillage system and amount of residue used, slope length and slope percentage, if any ongoing erosion is noticed, along with what watershed the site is in. |
Occasionally a site will need to be eliminated from the survey because it no longer applicable to monitoring and recording crops, tillage methods and the amount of residue left on the land. The most common reason for removing a site from the survey is due to the construction of a building. |
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The over-all trend in Vernon County is an increase in the amount of residue left on cropland. By taking a survey of the same points regularly, certain trends and practices become obvious. The practice of leaving residue on cropland to reduce erosion is evidence that the landowners and farmers in Vernon County value their agricultural land and are changing the way they farm in order to prevent erosion from diminishing the fertility of their land. |
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For more information on the Vernon County Transect Survey, contact our department at
608-637-5480. |
