Once this target level is determined, growers need a rapid, simple method to access residue amounts in the field. The line transect method has evolved over the past several years and is the preferred method of measuring residue cover. Let's review each of these. The percent ground cover is the proportion of the soil surface that is covered by crop residue and living plant tissue. Measuring ground cover requires a method or technique to compare the proportion of covered soil to the amount of unprotected soil or to the total area.
Photographic techniques are more credible but require considerably more time and effort.
Photographic slides of the ground surface are taken and the ground cover measured by projecting the image onto a grid to determine area. More recently computers have been used to analyze these images. A major disadvantage of this method is the long delay in getting an answer. In general, field sampling to determine residue cover involves selection of a set of sampling locations and then evaluation of cover at these locations. The line transect this type of method.