Cara Eisenpress - - Agtech

Enrich Your Satellite Data with In-Ground Soil Sensors

With more than one-third of the Earth’s arable land used for agriculture, satellites have been widely used to provide valuable data and a birds-eye view of farms, primarily to pinpoint crop disease or notice erosion. The U.S. Department of Agriculture, National Aeronautics and Space Administration, National Oceanic and Atmospheric Administration, and smaller independent organizations and businesses like Planet.com have all directed their attention to the ways that satellites can help farmers be more precise about farm management.

However, satellite data findings present some significant information gaps. At the micro-level, precise data on plots for small farms has been less accurate, mainly because not all satellites have the best imaging resolutions to be that micro-focused. Satellites also can’t see under the ground, or the ground itself when crops are fully grown, meaning there is limited information about a farm’s soils. While the technology has been improving and satellites have been getting better over time at analyzing smaller plots of land, they aren’t fully there yet.

Based on newer technology, in-ground soil probes can complement satellite data with a reliable and more complete set of details about fields, crops, soil, and more.

What Satellites Do for Farming

Satellite-based sensors give a wide overview of crops. Imagery beamed down from satellites can track where water flows to and from, show where there has been damage and erosion from weather events, and help create yield maps of specific areas of crops. They are also able to detect chlorophyll by picking up light emitted or absorbed by plants. It’s a perspective you can’t necessarily get from the ground.

Stanford University’s 2013 review of satellite data being used to understand crop yield gaps outlines the ways in which these high-in-the-sky sensors can be useful. For instance, they can help create yield gap profiles, looking at multiple years of satellite data to compare what has changed from year-to-year. Government organizations like the National Oceanic and Atmospheric Administration (NOAA) have been champions of this technology. NOAA’s satellites have played a role in delivering data to agronomists, monitoring drought conditions, mapping plant health and greenness of fields, and providing helpful soil-water availability estimates.

The International Space Station Agricultural Camera, which is operated by the Upper Midwest Aerospace Consortium, provides agronomists with key information on crop growth and fertility differences among crops. Precision farming by way of satellite data can give agronomists the opportunity to make adjustments in how they farm to better utilize their land.

Satellite data has also helped refine variable rate fertilization. Satellites—and sensors in general—helped to take the guesswork out of fertilizer application by showing which specific areas needed to be fertilized. And it clued many farm owners into the idea that they could use data delivered to their laptops to figure out nutrient management strategies, a big leap from earlier methods of managing fields.

Back when fields were smaller, farmers knew from practical experience which sub-areas were wetter and more fertile. “But as farms have grown from a few hundred acres to (as much as) 50,000 acres, farmers start to lose touch with their fields. Remote sensing provides a fabulous tool for looking at changes on small scales of space and time,” wrote Craig Daughtry, a research physical scientist at the U.S. Department of Agriculture, on the NASA Earth Observatory website.

On a larger level, the Global Agricultural Monitoring project is a collaboration between NASA, the University of Maryland, and the USDA Foreign Agriculture Service that uses NASA satellite and a web-based data analysis system to track the evolution of the growing season. The project observes crop conditions and tracks factors that harm crop productivity, like droughts, floods, and snow cover. It’s a tool that can play a big role in understanding what is happening to crops globally, particularly in developing countries hit by food shortages.

The Downside of Relying on Satellites Alone

Despite the advantages satellite data has brought to farm systems, it is not a complete system. While satellite imaging has certainly made advancements, fine resolution data is still not where it needs to be, according Stanford’s review. Farmers might not necessarily be getting the clearest or most accurate imaging.

Back in 1996, a report in Space of Service to Humanity looked at some of the limitations of remote, satellite sensors in Kenya. While this technology does useful work in assessing the health of crops around the world, it isn’t the most useful method for taking stock of crop health in places that are economically strained and lacking people trained to interpret and read the data. This same point of view can be applied domestically in the U.S.—the use of satellites can be costly and complex.

Then, there’s the variability of satellites themselves. Adverse atmospheric and weather conditions can impede a satellite’s ability to accurately read what is going on at the ground. If something goes wrong, you could potentially lose crucial data needed to get a composite understanding of the health of your crops over time.

The Benefits of Using Sensors

Teralytic’s NPK soil sensor offers an accurate and complete read of crop health—monitoring nitrogen, phosphorus, and potassium levels as well as soil moisture, salinity, aeration, air temperature, and humidity—so farmers get real-time data on nutrient management.

And our soil probe isn’t the only option out there. The latest earthbound sensors can measure fruit size, point to arable land, or track microclimates within a given farm. For those leery of the accuracy of satellite readings or looking for a more complete picture of their soil's health, this ground-based approach does a great job of giving the information farmers need about their crops in real time.

In-ground soil probes can complement satellite data with a reliable and more complete set of details about fields, crops, soil, and more.

What’s Next? How Sensors and Satellites Can Work Together

One helpful approach for agronomists is to pool the resources of both sensors and satellites. A 2017 report noted the benefits of using soil probes to corroborate satellite data. And a 2018 study review published in Sustainability also pointed to the fact that on-site sensors are key to corroborating the data transmitted down from a satellite.

Estimates derived from observations from space can go hand in hand with soil readings on the ground to supply farmers and agronomists with exactly the data they need to manage their work.