By Jeff Mulhollem
Environmental scientists and water resource managers need precise, high-resolution maps to reveal areas that farmers should avoid when planting crops, to limit polluting waters with phosphorus from fertilizer or manure. Making those maps has depended on an expensive, sometimes unavailable technology, but a team led by Penn State researchers has developed a cheaper approach that can be just as effective.
The researchers’ novel system, detailed in a paper available online ahead of publication in the June issue of Computers and Electronics in Agriculture, uses drones and photogrammetry, a technology that develops reliable 3D spatial information by analyzing overlapping 2D photographs. With this system, the team can map hydrologically sensitive areas — locations where water tends to collect or flow, creating high runoff risk — and phosphorus critical source areas, where phosphorus is likely to wash into streams and pollute them. They found that the drone-photogrammetry approach was cheaper, more accessible and nearly as accurate as conventional mapping.
The team tested the accuracy and resolution of maps created with the new method against maps made using a technology called LiDAR, which stands for light detection and ranging. It is a remote-sensing technology deployed from aircraft or satellites that uses laser pulses to measure distances to the Earth, creating precise, high-resolution maps. LiDAR is accurate but expensive and not always accessible, according to study co-author and team leader Patrick Drohan, professor of pedology in Penn State’s College of Agricultural Sciences.
Source : psu.edu