Fields under the watchful eye of observation satellites
Farmers will soon be able to accurately predict harvestable crop yields. In the context of the BELCAM project (Belgian Collaborative Agriculture Monitoring), the Department of Environmental Sciences and Management of the University of Liege is interested in developing tools capable of accurately predicting harvestable crop yields.
Financed by Belspo and piloted by the Catholic University of Louvain, BELCAM was started in 2014. The purpose of BELCAM is to apply new Earth observation systems to agriculture. Several Belgian and French partners are currently collaborating on the project including the Department of Environmental Sciences and Management of the University of Liege.
“Everyone has a specific role, at ULg, we are interested in predicting agricultural crop yields. In order to do this, we combine satellite images with crop growth-simulation software”, says Joost Wellens, a graduate in agricultural sciences who is coordinating the project for ULg.
A sentinel in the sky
Every ten days, Dr. Wellens receives satellite images of agricultural parcels captured by the European satellite “Sentinel-2”. Its twin satellite will be placed in orbit alongside it in 2017 which means that the researcher will receive images every 5 days. Launched in 2015, Sentinel-2 supplies free images to anyone who requests it. It is a huge asset to scientists: “Before the launch of Sentinel-2, these images were very expensive. It costs up to between 2,000 and 3,000 Euros to obtain a detailed satellite image of a rather small zone/region. Free images existed, but their precision was quite mediocre and was not sufficient for monitoring at parcel level”, explains Dr. Wellens.
The use of satellite images nonetheless presents a major disadvantage. “If the sky is overcast, nothing can be seen and therefore no predictions can be made”. This is where simulation software comes into play. “We can solve this problem by combining usable satellite images with simulation software; that will simulate/model the plant behavior in between two images. If we see that there are some errors as soon as an image becomes available, we can correct theprogram on the fly”, explains the scientist. Currently, scientists are using the AquaCrop software-model, made freely accessible by the United Nations Food and Agriculture Organization (FAO). AquaCrop is capable of calculating the evolution of the canopy, that is to say, the speed of canopy growth and decline, and phenological stages. By means of this information, the model predicts whether or not a harvest will be profitable.