To find out how much acreage is being farmed using conservation tillage, Agricultural Research Service scientists have gone up high — to satellites.
Soil scientists Dana G. Sullivan and Timothy C. Strickland, in the ARS Southeast Watershed Research Unit at Tifton, Ga., and Mark Masters, a resource economist at the Albany State University Water Policy Center in Albany, Ga., have created and evaluated conservation tillage maps using Landsat TM 5 imagery. They report their findings in the May/June issue of the Journal of Soil and Water Conservation.
Conservation tillage is one of the nation's most widely adopted conservation practices. It refers to any method of tillage that minimally disturbs the soil surface, leaving at least 30 percent of crop residue cover after planting. Conservation tillage has been credited with improving soil quality, reducing runoff, and lowering fuel costs for farmers.
This satellite mapping technique shows promise for streamlining national efforts to monitor changes in conservation tillage adoption over time, evaluate the efficacy of conservation tillage placement, and reduce the need for time-consuming field surveys to ensure compliance with federal cost-sharing programs.
In 2004, an estimated 113 million acres of the nation's cropland were in some form of conservation tillage. However, no national monitoring system is in place to continue to monitor these efforts on a regular basis.
Using satellite imagery, Sullivan's team collected data over a 230,000-acre area centered on the Little River Experimental Watershed in Tifton. It is one of the 14 designated national benchmark watersheds included in the USDA Conservation Effects Assessment Project-Watershed Assessment Study. Along with the satellite data, researchers conducted a ground-based “windshield survey” that identified 61 conservation tillage and 77 conventional tillage sites.
Results from this study provide a foundation to begin evaluating the impacts of conservation tillage adoption and placement in the Little River Experimental Watershed. Satellite-derived maps created during the study directly contribute to a national effort to evaluate the results of federally cost-shared conservation practices.