Landsat & LiDAR Field Drainage & Yield Assessment (see below for details)
Related pages:
LiDAR-Based Elevation, Drainage & Topography Layers
Drainage Analysis with LiDAR-Based Elevation and Landsat (pdf)
Images transition every 4 seconds (or click arrows or dots); description appears below.
In the graphics above, lighter shades of gray are higher values and correlate to higher yield; light blue is flow accumulation; dark blue outlines sinks (where ponding can occur). The field shows overall consistent spatial patterns of higher and lower areas of predicted yield (as well as good drainage) and is a good candidate for management zone application.
The simplest way to use Landsat to assess spatial yield stability and drainage impact on yield for a field is to view Landsat imagery for many seasons with the field boundary, flow lines, and sinks overlain (the amount of correct imagery will vary per field; the field above is in a Landsat overlap zone so there is more imagery than most locations). When assessing data, ignore pixels near the field boundary that average values. If a field is well-drained, relative yield patterns in lower and higher ground areas will be spatially consistent; flow lines run through areas of low ground soil which typically should be higher yielding for a field if it is well-drained. For corn and soybean, a Landsat-based value that correlates relatively high to yield needs to be determined on an image-by-image basis. Corn imagery should be from V12 to the onset of tassel which can be determined based on viewing imagery. For soybeans, imagery should ideally be from R2 to R6; however, imagery from earlier stages can also be applied if necessary.