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Geospatial tech ascertains presence of nematodes

Mississippi, US: Researchers at Mississippi State University (MSU) developed a solution using remote sensing technology to analyse the presence of certain nematodes in cotton fields so producers can increase profits.
MSU associate professor of nematology Gary Lawrence and Giles Distinguished Professor of Electrical and Computer Engineering Roger King used remote sensing technology to battle reniform and root-knot nematodes, which are the No. 1 cotton pest in Mississippi, Alabama and Louisiana. “These worm-like parasites live on plant roots and feed off the plant’s juices, weakening the plant and resulting in lower productivity,” Lawrence said.
Earlier research indicated that the reflectance values of cotton plants infected or stressed with the reniform nematode were different than un-infected plants. Lawrence and King decided to try hyperspectral imaging. This technique uses a sensor to collect thousands of samples of reflected energy from cotton plants across the visible and near-infrared electromagnetic spectrum to determine the presence and numbers of nematodes.
Lawrence first conducted controlled tests in small plots on MSU’s North Farm. Then he worked with cotton producers to determine if he got the same results in fields naturally infected. Four reflectance measurements were taken: the plant canopy, the soil, the plant canopy and soil, and a single leaf. He used an Analytical Spectral Device to gather data but needed a way to make sure the data accurately gauged the presence of nematodes.
“These kinds of projects require interdisciplinary efforts,” King said. “We brought together the agricultural and engineering disciplines to explore what technology could do. The engineering students wrote algorithms and software programs to see which mathematical algorithm would analyze the data best to correlate with the nematode sampling.”
The software created by electrical engineering graduate students matched reflectance data with the actual nematode counts collected when the reflectance data was gathered. Nematode sampling is a multi-step process that involves extracting the nematodes from the soil and suspending them in water so they can be viewed under a microscope and counted.
Compared to the nematode counts, the data collected through hyperspectral imaging was 75 to 100 percent accurate. The data was used to generate a field map showing areas of low, medium and high nematode populations. From that, a prescription map for applying different amounts of nematicide was created. The next research question was practical: would site-specific applications of the product be helpful?
“What we discovered was that the variable rate application had three significant results,” Lawrence said. “For the producers, the yields were higher, which increases profits. Plus they saved money by applying only the amount of chemical required rather than blanketing their field with the amount needed to treat the highest population of nematodes found in their soil samples. The third benefit is to the environment, because site-specific applications reduce the amount of chemical used.”
Source: msucares.com