Measurement of nitrate-nitrogen concentration in soil based on absorption spectroscopy
First Claim
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1. A device for measuring the nitrate-nitrogen concentration in soil based on attenuation over a spectral operating range, the device comprising:
- a light source that generates light that spans the spectral operating range, the spectral operating range including wavelengths at least as short as 230 nm;
a detector having a sensitivity that spans the spectral operating range;
a sample chamber configured to contain a soil-extractant mixture, the light propagating from the light source to the detector and attenuated by the soil-extractant mixture in the sample chamber, the detector generating a soil spectral signal that indicates the light received by the detector at different wavelengths across the spectral operating range; and
a processor coupled to the detector, wherein the processor estimates an attenuation spectrum of the soil-extractant mixture over the spectral operating range based on the soil spectral signal, and estimates the nitrate-nitrogen concentration based on the attenuation spectrum, wherein the processor, when estimating the attenuation spectrum, removes interference due to scattering from soil particles in the soil-extractant mixture using one of spectral deconvolution and curve-fitting.
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Abstract
The nitrate-nitrogen concentration in soil is estimated based on the nitrate-nitrogen 200 nm absorption peak. In one embodiment, a device measures the attenuation spectrum of a soil-extractant mixture over a wavelength range that includes wavelengths in the vicinity of the 200 nm absorption peak (the spectral operating range) and then determines the nitrate-nitrogen concentration based on the attenuation spectrum.
37 Citations
36 Claims
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1. A device for measuring the nitrate-nitrogen concentration in soil based on attenuation over a spectral operating range, the device comprising:
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a light source that generates light that spans the spectral operating range, the spectral operating range including wavelengths at least as short as 230 nm; a detector having a sensitivity that spans the spectral operating range; a sample chamber configured to contain a soil-extractant mixture, the light propagating from the light source to the detector and attenuated by the soil-extractant mixture in the sample chamber, the detector generating a soil spectral signal that indicates the light received by the detector at different wavelengths across the spectral operating range; and a processor coupled to the detector, wherein the processor estimates an attenuation spectrum of the soil-extractant mixture over the spectral operating range based on the soil spectral signal, and estimates the nitrate-nitrogen concentration based on the attenuation spectrum, wherein the processor, when estimating the attenuation spectrum, removes interference due to scattering from soil particles in the soil-extractant mixture using one of spectral deconvolution and curve-fitting. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A method for measuring the nitrate-nitrogen concentration in soil based on attenuation over a spectral operating range, the method comprising:
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generating light that spans the spectral operating range and includes wavelengths at least as short as 230 nm; providing a soil-extractant mixture that attenuates the light; detecting the attenuated light; generating a soil spectral signal that indicates the light detected at different wavelengths across the spectral operating range; estimating an attenuation spectrum of the soil-extractant mixture over the spectral operating range based on the soil spectral signal, wherein estimating the attenuation spectrum includes removing interference due to scattering from soil particles in the soil-extractant mixture using one of spectral deconvolution and curve-fitting; and estimating the nitrate-nitrogen concentration based on the attenuation spectrum.
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Specification