Field Health imagery is most commonly used for efficient scouting and tracking for early-crop establishment. However, you can also use the imagery to support your harvest. Here are three ways:
1) Managing harvest progress
If you manage a large farm or work remotely then you can use Field Health to monitor which fields have been harvested on your farm from space.
Jaco Theron is a farm manager in Arizona, as part of his role he manages over 7000 ha of Alfalfa production. With the appropriate inputs, farms in Arizona and California can get 8 to 10 cuttings from one alfalfa field in a year but with drip irrigation that number is even higher (source).
Using Field Health Satellite imagery he can track what work has been done and what still needs to be done. Field health imagery shows NDVI (Normalized Difference Vegetation Index). This provides an indication of field health, by measuring the amount of green plant biomass. You can read more about this here.
“The satellite maps work great for me. On each image, I can clearly see which alfalfa fields have been cut. With 7000 ha to manage the satellite imagery can be used to monitor the progress of the crop growth and harvest.” Jaco Theron, Arizona
2) Tracking crop growth stage – To Harvest or not to Harvest?
You can use Field Health to get an insight into which fields are ready for harvest. At the end of the season, as crops mature before harvest, the colours of the Field Health imagery changes. Field Health maps show as yellow – orange (lower NDVI values) the closer that part of the field is to the ripening stage.
In this section, we will be zooming into one wheat field and see how the imagery changes throughout the end of the season. The first Image from June 20th shows a crop field with high vegetation growth. The crop in the south-west corner of the field is starting to reach maturity.
Field Health maps from July 20th shows changing colour to yellow and oranges as the NDVI level reduces. The change in imagery is consistent through-out the field. By July 30th the NVDI level has reduced further to organges and reds. The crop was harvested shortly after.
The final bright red images from August 9th 2021 shows the Field Health imagery that is shown when the field has been harvested and the land has returned to soil.
Was this the right time for harvest? Or should harvest have happened earlier, when NDVI was the higher? You can find more information about the ability to predict the best harvest date from NDVI imagery in this this publication.
3) Predicting crop performance and variation
Although yield mapping is becoming more common, it is not available to every grower due to the costs. However, Field Health imagery is readily available to everyone and offers valuable insight.
By assessing your Field Health maps you can start to predict any variation in your potential yields come harvest, while also identifying any higher yielding areas. The image below shows how a late season Field Health image (May 30th) can correlate to a yield map. This provides a valuable tool for those without a yield mapping enabled combine.
I hope this has helped. We would love to hear from you if you have experience with the imagery or are interested in trying. Email firstname.lastname@example.org to talk to use.
Field Health is available as part of fieldmargin Pro. See how it could help on your farm with a free 14-day trial. No credit card required.