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ARS Home » Southeast Area » Tifton, Georgia » Southeast Watershed Research » Research » Publications at this Location » Publication #190081
Title: EVALUATING TECHNIQUES FOR DETERMINING TILLAGE REGIME IN THE SOUTHEASTERN COASTAL PLAIN AND PIEDMONT

Author
item Sullivan, Dana
item Truman, Clinton
item Schomberg, Harry
item Endale, Dinku
item Strickland, Timothy - Tim

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/3/2006
Publication Date: 9/9/2006
Citation: Sullivan, D.G., Truman, C.C., Schomberg, H.H., Endale, D.M., Strickland, T.C. 2006. Evaluating techniques for determining tillage regime in the southeastern coastal plain and piedmont. Agronomy Journal. 98:1236-1246 (2006). GRACEnet Publication.

Interpretive Summary: Reduce tillage and residue management can have significant impacts to soil and water quality, primarily through the accumulation of soil organic carbon. Yet, current methods of tillage and crop residue cover assessment are inappropriate for watershed scale determinations. This study was designed to compare the line transect method currently used by the USDA Natural Resource Conservation Service, with remotely sensed estimates of crop residue cover at two sites in Georgia. Remotely sensed data were acquired in the visible, near-infrared and thermal infrared regions of the light spectrum. Ground truth data include digital, color images, soil water content, ambient air temperature, and soil texture. Results showed that remotely sensed data could be used to detect differences in crop residue cover at both study sites. Using remotely sensed data, three new crop residue cover indices were developed and a threshold value for differentiating between conservation and conventional tillage was identified for each site. Crop residue cover performed similarly to the line-transect estimates explaining > 84 % of the variability in crop residue cover. Remotely sensed estimates were best when the crop canopy was < 25 % closed. Our data indicate that remote sensing of crop residue cover shows promise as a method for rapid watershed scale assessment of conservation tillage adoption. GRACEnet Publication.

Technical Abstract: Reduce tillage and residue management can have significant impacts to soil and water quality, primarily through the accumulation of soil organic carbon. Yet, current methods of tillage and crop residue cover assessment are inappropriate for watershed scale determinations. A major goal of this study was to compare new remote sensing indices with the currently accepted line-transect approach for assessing variability in crop residue cover. Experimental plots were located in two distinct physiographic regions in Georgia: the Piedmont and Coastal Plain. Treatments consisted of no-tillage or conventional tillage at the Piedmont site, and strip-tillage or conventional tillage at the Coastal Plain site. Remotely sensed data were acquired three times prior to canopy closure, using a handheld multispectral radiometer (485 –1650 nm) and thermal imager (7,000 – 14,000 nm) at each site. Coincident with remotely sensed data collection, digital images were acquired for residue cover classification and line-transect assessments. Soil texture and soil water content were measured to assess the impact of changes in soil background reflectance on crop residue assessments. Results showed that differences in crop residue spectral response were greatest in the 1240 –1650 nm region under dry conditions at both sites. Crop residue cover indices using the 1650 nm region successfully differentiated between conservation and conventional tillage, and performed similarly to the line-transect estimates explaining > 84 % of the variability in crop residue cover. Remotely sensed estimates were best when the crop canopy was < 25 % closed. Using the crop residue cover indices, threshold values for identifying conservation tillage at each site were established. Our data indicate that remote sensing of crop residue cover shows promise as a method for rapid watershed scale assessment of conservation tillage adoption.