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Title: SOIL MOISTURE AND ORGANIC MATTER PREDICTION OF B-HORIZON SOILS USING AN NIRSOIL SENSOR

Author
item Hummel, John
item Sudduth, Kenneth - Ken
item HOLLINGER, STEVEN

Submitted to: Computers and Electronics in Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: 7/20/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Quantification of spatial variability of soil parameters is important to the successful implementation of Site-Specific Management (SSM). Changes in soil parameters may occur on a finer spatial resolution than can be documented with manual and/or laboratory methods due to cost of the sampling and analysis procedures. Therefore, there is a need for the development of sensors to more accurately characterize within-field variability. Extensive laboratory tests using a range of surface horizon soil types were used in the development of a near infrared (NIR) reflectance soil sensor. A prototype soil sensor has been shown to be capable of predicting soil organic matter and soil moisture across a range of surface horizon soil types. Further research has documented the sensor's accuracy in predicting soil organic matter and soil moisture across a expanded geographical range. This paper reports research documenting the ability of the sensor to predict soil moisture and soil organic matter contents of B-horizon soils. Three soil cores (5.56 cm dia. x 1.4 m long) were collected at each of 16 sites across a 144,000 km2 area of the U.S. Cornbelt. Cores were segmented and frozen prior to subsampling at eight depth increments. Samples were tested at six soil moisture tensions ranging from air-dry to 0.033 Mpa (field capacity). Spectral reflectance data (1640 nm - 2640 nm) were obtained in the laboratory on both undisturbed and prepared soil samples, using the same procedures reported in previous studies. Data were averaged to a 40 nm bandpass and transformed from reflectance to optical density [OD, defined as log10 (1/reflectance)].