Evaluating soil properties of CRP land using remote sensing and GIS in Finney County, Kansas

The Conservation Reserve Program (CRP) began in 1986 with the primary purpose of reducing soil erosion. It also was intended to help the development of sustainable agriculture and associated environmental harmony. However, its effectiveness has been questioned because of the large costs and extensive staff required to conduct the program. The objectives of our study were to test procedures for integrating remote sensing and geographic information systems (GIS) techniques to evaluate the present CRP in terms of its main goal, and to give recommendations for the future of the program in Finney County, Kansas. Three seasonal Landsat Thematic Mapper (TM) images were used to derive the land-use/land cover (LULC) map. This information was incorporated with spatial dimensions of soil surface horizon thickness, surface horizon texture, soil family, soil subgroup, and soil erodibility index (EI), all of which were extracted or calculated from the Natural Resources Conservation Service (NRCS) soil survey geographic (SSURGO) data base. With GIS techniques, calculation of EI was more efficient and the value was more accurate than that calculated by hand. We found the average EI of the county to be 20, with the highest EI of 77 in the southwest portion of the study area. CRP land had higher soil fertility and a lower EI than land currently used for farming; therefore, the CRP for this county did not necessarily include the lands most susceptible to erosion. We suggest continuing the CRP program in Finney County, because the soils are generally at serious risk of erosion. We also suggest modifying the eligibility rules of the program in order to target the most environmentally sensitive lands.