What satellites can’t see: US crop forecasters walk and learn

For decades, government satellites have been taking detailed photographs of crops around the world that are now being tapped by traders like Cargill Inc. to gain an edge in global grain markets.

But the United States Department of Agriculture (USDA)—the benchmark in forecasting domestic crops—says the images by themselves still can’t be relied upon to predict annual corn, wheat or soybean harvests. Instead, the government’s main source of information remains farmer surveys and random field samples.

“Satellites are not advanced enough to differentiate crop acres yet, so there is a loss of precision,” said  Seth Meyer, the chairman of the World Outlook Board, the USDA agency responsible for world crop forecasts. “This technology is going to get better, but right now it’s just one tool in our forecasting toolbox.”

Getting accurate assessments of major US crops valued at more than $100 billion last year is a recurring challenge for traders, consumers and farmers. Crop conditions can change with the weather over the long growing season, so any early forecasts may be far off the mark when harvest rolls around.

Some scientists expected satellite images to eventually make the job easier. The US has been taking pictures from space since the 1970s to track everything from the weather to troop movements. But it wasn’t until the last few years that advances in digital technology and computing power made those billions of images more useful in crop forecasting.

Making switch

Statistics Canada, the government agency that produces the country’s monthly crop forecasts, already is using the technology in key crop assessments. In 2016 StatsCan switched to using only satellite- and weather-based models for a monthly production report published in September, saving about C$150,000 ($95,000) in farm and field surveys for that month. Other reports during the year still rely on the surveys.

“There’s been a lot research put into this model to verify its robustness,” said Gordon Reichert, head of remote sensing analysis at Statistics Canada. “Feedback from the grain companies in Canada has been favorable.” Satellites scan thousands of square miles of agricultural land and record daily changes in areas as small as two dining tables, mostly by analyzing how green the fields are from planting to harvest. Machine-learning algorithms then match those characteristics with historical data and production results to make forecasts.

Computer models

In 2008 the US began offering its satellite data and three decades of history for free, and the European Union made all its space-based observations public in 2013. Companies like Descartes Labs Inc., TellusLabs Inc. and Planalytics Inc. used the information to develop computer models to make all kinds of predictions, including for grain production. Other companies even sent their own monitoring devices into orbit and market the data to farmers looking to catch nutrient deficiencies or diseases soon enough to be treated.

It’s an effective early warning tool, said Bruno Basso, an environmental scientist at Michigan State University and co founder of CiBO Technologies in Cambridge, Massachusetts.For example, the world was caught off-guard in 1972 when harsh weather led to a big drop in wheat harvests in the former Soviet Union. The country kept the damage secret and filled the shortage with 440 million bushels of US wheat, or 28 percent of what American farmers produced that season using subsidies provided by the US government. Prices tripled, and the Soviet purchases were dubbed the “great grain robbery” by traders.

 

Image Credits: Bloomberg

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