Weeds have a negative impact on yields. “Even one weed per 100 feet of (soybean) row can impact yield,” says Rich Keller, Editor, AgProfessional Magazine in the article Even one weed impacts yield.
Research from The South Dakota State University showed that early season weed competition for resources (light, water, etc…) resulted in as much as 40 bushels per acre yield loss. This is certainly not a small matter!
The difficult part is identifying areas in the field where weed pressure exists. Conventional scouting methods can certainly find instances of weed pressure, but it is extremely difficult to see each and every part of each and every field from an economic perspective.
One of, if not the, most economical and effective means of identifying weed pressure is with an aerial image, especially an NDVI. The below set of images shows that there is a variation in the field. At first glance, it looks like a very small portion of the field is extremely “healthy,” as shown by the dark green color in the image. Upon further investigation in the field, the scout found that there was indeed something causing the variability, weeds!