Submitted to: Global Worshop on High Resolution Digital Soil Sensing and Mapping
Publication Type: Proceedings
Publication Acceptance Date: January 14, 2008
Publication Date: February 5, 2008
Citation: Kitchen, N.R., Sudduth, K.A., Kremer, R.J., Brent, M.D. 2008. Sensor-based mapping of soil quality on degraded epiaqualf landscapes. In: Proc. First Global Worshop on High Resolution Digital Soil Sensing and Mapping. February 5-8, Sydney, Australia [CDROM]. IUSS Working Group on Digital Soil Mapping. 2008. Interpretive Summary: Much of the claypan soil area of the U.S. Midwest has been under cultivation for only about a century. However, because these soils were vulnerable to water erosion, soon after the grasslands were plowed they lost topsoil, a critical component for plant nutrients and soil water storage, which are important aspects of “soil quality”. In general, soil quality is a broad concept that includes a soil’s ability to grow plants and respond to current management practices so there is minimal negative impact to the environment. For claypan soils, decreased soil quality caused by erosion is not uniform over fields. This research was conducted to develop cost-effective sensors and methods for mapping properties related to soil quality. We found that soil electrical conductivity, aerial imagery, yield mapping, and on-the-go soil compaction sensing were valuable tools for collecting soil quality information on claypan soils. Soil electrical conductivity was especially helpful in identifying topsoil loss through erosion. Areas with severe topsoil loss exhibited reduced grain yield, lower plant available water capacity, and slower water infiltration into the soil profile. We also found these same areas to have higher levels of sub-soil nutrients. We conclude that by employing a number of different automated sensors designed for rapid surveying of fields, soil quality information can be mapped to improve management decisions. With these maps in hand, land managers can identify what types of remediation practices to use. The maps also can be a basis for targeting those locations most in need of conservation practices, a concept referred to as precision conservation. Characterizing important soil quality parameters and how they change within fields will provide a basis for future management strategies helpful in developing sustainable food, fuel, and fiber production systems.
Technical Abstract: Claypan soils (Epiaqualfs) in the central USA have experienced severe erosion as a result of crop tillage practices of the late 1800s and 1900s. Because of the site-specific nature of erosion processes within claypan fields, research is needed to achieve cost-effective sensing and mapping of soil and landscape properties that quantify the soil’s current ability to produce crops and provide ecosystem services- the concepts of soil quality. In this research ECa sensors, aerial imagery, yield mapping, and a horizontally-operated penetrometer were used for high resolution mapping of soil quality indicators on a 36-ha claypan soil field in Missouri. Field areas experiencing the most erosion now have reduced grain production, lower plant available water capacity (PAWC), and slower infiltration. These same areas have higher soil penetration resistance (at 30 cm) and greater sub-soil nutrients. The conclusion of this synthesis is that combining sensor-based information provides a much clearer picture of spatially-important characteristics of claypan soil quality, and can be used by land managers to targeted precision conservation practices.