How to Use Your Early-Season Crop Health Imagery

May 10, 2017

Precision agriculture started by making it easier to think of fields as variable rather than uniform blocks of soils. Initially, yield maps were used as a powerful tool to document the differences in how variable the field was, and this created a desire to learn how to manage those differences in future seasons. As remote sensing technologies continue to improve, they now offer the potential to evaluate the variability in a field within a season and allow growers the opportunity to correct problems and improve efficiency.  

FarmLogs Crop Health Imagery gives you access to in-season and historical satellite imagery for each of your fields. One of the most frequent questions I receive from growers is, “How do I best use satellite imagery?” In some ways, that’s similar to asking, “What is the best use of a screwdriver?”

Although everyone may find something different in their satellite imagery, there are few general concepts of what to look for:


What to look for in your early season imagery

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1. Is there variability in the image?

If the answer is no, there is not much more to look at.
If the answer is yes, then you’ll want to look deeper.


2. If there is variation, is it differences in the crop or are you looking at bare soil?

Even though some row crops may be 12 inches tall, they may not cover enough of the ground to be seen in some imagery or indexes because of the large amount of uncovered soil.


3. If there is variability in vegetation, is it man made variability or natural field variation?

Natural field variation may or may not be an issue that can improved.


4-A. If the variation is man made, is there a consistent pattern or intermittent?

If there is a more consistent pattern, can you determine the cause because of the width and angle of the pattern? Some tillage and N applications may occur at an angle. A 60 ft cycle could be center of a 60 ft bar, or the outer edge of a 30 ft bar, or a plugged knife/nozzle ⅔ of the way in a 40 ft bar.

If there is a more intermittent pattern, can you determine the cause because of the size, shape, and locations in the field? Is is more frequent in lower heavier areas? Is the width the full width of a piece of equipment or slight overlap or guess row errors?


4-B. If the pattern is more a natural variation, is it related to the patterns of the soil?

If the answer is no, the variation could indicate problems like insects, hail, or weed patterns. It would be good to scout to see if it is something worth taking corrective action this season.

If the answer is yes, the variation could indicate problems like compaction, germination or emergence problems, nitrogen stress in low lying areas, insects, or weeds. It would be good to scout to see if it is something worth taking corrective action this season.


You know your fields and your operation better than anyone else. Using this type of process when looking at satellite imagery can help you find a possible fix for potential problems in your fields. While satellite imagery is not a replacement for good management, it can help you strengthen your management practices.

 

FarmLogs

Dr. Tracy Blackmer

Author

Dr. Tracy Blackmer Dr. Tracy Blackmer is an expert agronomist with over 20 years of experience incorporating precision agriculture technologies in agronomic management for growers. His work has included organizing a network of over 1,000 growers from 12 different states to conduct Nitrogen adaptive management using imagery, yield response, and other feedback assessments. Tracy also focuses on implementing large-scale, on-farm trials that are easy for growers to implement and result in improved agronomic recommendations. His work as the Vice President of Science at FarmLogs includes developing tools that improve local management for growers through better and simplified recommendations and monitoring.