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Submitted to: Soil Erosion for 21st Century Symposium
Publication Type: Proceedings Publication Acceptance Date: 1/3/2001 Publication Date: 1/3/2001 Citation: In: J.C. Ascough II and D.C. Flanagan, Proc. Int. Symp. Soil Erosion Research for the 21st Century, 3-5 January 2001, Honolulu, HI. St. Joseph, MI: pp 206-209. Interpretive Summary: The laser distance method of measuring a silhouette area index for standing residue provided consistent results for the limited number of scans obtained. The laser method consistently underestimated the silhouette area index when compared to hand counts with height and diameter measurements. A constant ratio of scanned to counted silhouette area index across varying densities of standing residue indicates that all stems are being counted and consistent measurements are being obtained. A low ratio indicates that stem sihouette area is being underestimated. Sampling time is about 1 minute for a 2 meter scan. Technical Abstract: Crop residue standing above the soil surface is 5 to 10 times more effective in preventing wind erosion than the same mass of residue laying flat on the soil surface. Managing tillage operations and designing tillage tools to preserve standing residue require accurate and objective measurement before and after field operations. Manual methods of counting and measuring standing residue provide accurate but slow measurements, making it costly to obtain representative samples for field-size areas. a device was developed using a laser distance sensor to obtain estimates of stem counts, width, and height. These estimates were compared to values obtained using manual counting and measurement. At a scan speed of 2 meters per minute in wheat straw with a stem population of 800 per square meter, counts were estimated accurately but width and height were understimated consistently. Keywords: Wind erosion, Standing residue, Air Quality, Laser scanning |
