College of Agriculture & Natural Resources

The Future in Farming

College of AGNR researcher focuses on precision agriculture
Dr. Josh McGrath, associate professor in the Department of Environmental Science & Technology
Image Credit: 
Edwin Remsberg

(Note: Dr. Josh McGrath no longer works for the University of Maryland as of August, 2014. The following article appears in the Spring 2014 edition of MomentUM magazine which focuses on the College of AGNR's efforts to preserve, protect and restore the Chesapeake Bay. Read the online version here.)

If you ask three farmers what precision agriculture is, you’ll probably get three different answers. Some will say GPS guidance and steering while others will talk about variable-rate seeding options and another may mention crop yield monitors on combines. And really, they are all correct – precision ag is about as broad as, well, the term agriculture.

For Dr. Joshua McGrath, precision ag is just “old-school agronomy.” By using technology, farmers can improve production through basic seed to soil contact or precisely knowing their fields – how much seed, water and nutrients are needed and when. Which means precision ag is one more tool for Maryland farmers in protecting the Chesapeake Bay.

Dr. McGrath, associate professor in the Department of Environmental Science & Technology, is leading the University of Maryland’s precision ag research through the Laboratory for Agriculture and Environmental Studies (LAES), which focuses on soil fertility, nutrient management and water quality.

Unlike many of his colleagues, Dr. McGrath’s research is done not in a lab or test field, but directly with the farmers in their full-scale fields. One of Dr. McGrath’s research projects has been studying the Green- Seeker technology to apply the correct amount of fertilizer to the plants in the field based on precisely what the plant tells you it needs. “Nitrogen requirements vary across a field and from year to year. GreenSeeker and tools like this are the first opportunity we’ve had to take a serious look at adjusting to the spatial and temporal variability and actually apply the correct rate.”

The GreenSeeker is attached to the booms of a sprayer and scans the chlorophyll levels of the plants, then uses an algorithm (developed with the help of Virginia Tech) to determine the application rate, which changes every second. The readings are then measured and recorded in a hand-held system that allows the farmer to integrate it with harvest yield readings. The goal is to reduce the nitrogen application rate by 20% in corn and 10% in wheat, yet maintain the same yield.

“It’s a simple idea, really, but it requires a lot of data and extra work to make sure it’s accurate,” says Dr. McGrath.

Read the complete article in the current issue of MomentUM by clicking here.

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