Corn is an essential crop in the United States. As of 2023, U.S. farmers planted approximately 94.9 million acres of corn. This represents about 95% of the total feed grain production value in the United States. Half of this corn goes to feeding livestock, while the rest is processed into a wide range of products, from sweeteners to ethanol. As demand for corn grows, keeping track of crop performance becomes important. The ability to forecast yields and adjust farming practices can mean the difference between success and failure.
Factors that affect corn yields include water availability and nitrogen supply, soil health, and disease management. Given the complexity of these factors, new technologies are needed to help farmers and scientists understand and optimize corn production. One of the most exciting advancements is spectroscopy, which provides detailed data on crop health and productivity in real-time. This technology can help farmers improve their yields, reduce waste, and make faster decisions about how to manage their fields.
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Imaging Spectroscopy: A Tool for Precision Agriculture
By using spectral data, we can assess everything from biomass to water content in the leaves. For corn, this means more accurate predictions about yields and better insights into how environmental stressors, like drought or nutrient deficiencies, are impacting the plants.
Spectroscopy has already been used in agriculture through several airborne systems, like the AVIRIS and the AISA Eagle & Hawk, which can capture high-resolution spectral data. Near-infrared spectrometry device is especially useful, as it allows a closer examination of plant materials data. This technology helps to understand plant physiology, such as grain consistency.
NASA’s proposed HyspIRI mission would revolutionize corn yield management through advanced hyperspectral imaging. Operating on a 19-day cycle with a 60-meter resolution, the system would detect early physiological changes in corn crops before visible symptoms appear. This capability would allow farmers to track how their corn responds to various environmental conditions and take prompt corrective actions to optimize yields. The mission’s global mapping abilities would provide unprecedented insights into corn crop health and performance across different growing regions, directly supporting efforts to increase agricultural productivity through spectroscopic monitoring.
Improving Corn Yields Through NIR Spectrometry
At the USDA Beltsville Agricultural Research Center, the Optimizing Production Inputs for Economic and Environmental Enhancement (OPE3) project has been using Near-Infrared (NIR) spectrometry to optimize corn yields. Since 2009, the OPE3 project has been investigating how various nitrogen treatments affect corn growth, with treatment levels ranging from 0 to 280 kg of nitrogen per hectare. These nitrogen treatments simulate real-world agricultural conditions where nitrogen availability varies, and NIR spectrometry plays a crucial role in monitoring and assessing the impact on crop health and yield.
NIR spectrometry has enabled the research team to assess corn health and predict potential yields more accurately. During the reproductive stages of corn (R1 to R3), NIR-based measurements were taken in conjunction with traditional field measurements like Leaf Area Index (LAI), fraction of Absorbed Photosynthetically Active Radiation (fAPAR), and grain yield. By combining these NIR spectral data with field observations, the team created detailed maps of crop stress and performance across the field, which were used to identify areas needing targeted management.
A core tool in this project was the ENVI Agricultural Stress Classification Tool, which utilized NIR-derived vegetation indices like the Normalized Difference Vegetation Index (NDVI) and Photochemical Reflectance Index (PRI). These indices, combined with additional NIR spectral bands such as water absorption, allowed the researchers to detect crop stress caused by nutrient deficiencies or water shortages. This capability is essential for precision farming, where small adjustments can significantly impact yield.
Furthermore, Spectral Angle Mapping (SAM) was applied to correlate spectral data with field observations. This technique refined the ability to identify high and low-performing areas within the field. The analysis revealed that early to mid-day NIR spectral data from the corn canopy could reliably predict grain yields at harvest. This predictive capability makes NIR spectrometry a powerful tool for improving corn yields, helping farmers optimize inputs and manage crop stress more effectively, ultimately leading to higher yields.
Spectral Observations Across Multiple Scales
Researchers employed a range of spectroscopic tools to further refine their predictions, from ground-based radiometers to satellite imaging. A spectral radiometer (ASD-FR FieldSpec Pro) was used to measure leaf and canopy radiance across a wide spectral range, from 350 to 2500 nm. These ground-level observations were then compared with aerial data from the AISA Eagle & Hawk imaging spectrometer, which was flown over the field site at a 2-meter ground resolution. Hyperspectral satellite data was also collected using the EO-1 Hyperion sensor, which offers a 30-meter ground resolution.
This multi-scale approach provided a comprehensive view of the corn field, which helped researchers detect subtle changes in crop health that might not be visible at just one scale. For example, at the leaf level, they observed a shift in the red-edge spectral region, indicating stress in areas where crops were underperforming. At the canopy level, these shifts became less visible but were still detectable in the NIR region, which is important for understanding photosynthetic efficiency.
The data collected from these different levels was consistent. Spectral features associated with reduced crop performance, such as increased reflectance in the green region (500-600 nm) and a shift in the red-edge region, were apparent across all scales.
Spectrometry’s Role in Sustainable Farming
Precision agriculture is the farming of the future, and spectrometry is just right at the heart of this transformation. Applying sophisticated spectrometric techniques gives the farmer rich information about crop health for better decisions on when and how to intervene. The world’s population continues to increase, hence increasing the demand for food. Technologies such as spectrometry will thus be important in optimizing farming and enhancing food security.
The promising tools include SCIO’s handheld spectrometers. These portable devices bring the power of spectroscopy right to the farmer. They allow real-time monitoring of crop health throughout the growing season. With immediate feedback, farmers can detect early signs of stress, nutrient deficiencies, or pest damage that allows quicker intervention.
Spectrometry also plays the most important role in sustainable farming. It helps to lessen agriculture’s environmental impact. By locating areas that need attention, farmers can apply the optimum amount of fertilizers, pesticides, and water. This will prevent unnecessary waste and conserve natural resources. It reduces input costs, which, in turn, increases profitability and allows for more sustainable yields. In short, spectrometry grows more with less, which is very important in sustainable farming.
Conclusion
Spectroscopy is transforming the way we approach corn farming. By offering a detailed, real-time look at crop health, this technology helps farmers make more accurate decisions about managing their fields.
With ground-based tools like those from SCIO, the use of spectroscopy in agriculture is only set to grow. The technology will integrate into everyday farming practices, which will help to increase yields and create a more sustainable agricultural environment.
