Purdue Agronomy Farm Soybean Row Direction (791810)

<p>The objective of the experiment is to determine the effect of rows and row direction, variables in the area of cultural practices, on the reflective response of a soybean canopy as a function of azimuth and zenith sun angles. The design of the experiment involved 11 plots. One plot was planted in east-west and north-south rows 25 cm wide to obtain, at later growth stages, a canopy with negligible row effects. A second plot was bare soil, providing an opportunity to monitor the reflectance of the soil background of the soybean plots. The remaining nine plots were planted in soybeans with 76 cm wide rows with the following azimuthal directions: 90-270, 105-285, 120- 300, 135-315, 150-330, 165-345, 180-360, 210-030, and 240-060 degrees. The row directions were selected to maximize the probability of obtaining data during the morning hours when cloud conditions are more favorable for data collection than in the afternoon. Reflectance data were acquired at 15 minute intervals throughout the day on three days, representing three canopy growth stages.<br />
Data analysis involves mathematically modeling the effect of combinations of sun azimuth and sun zenith angles on the reflectance from a row crop of soybeans. The experiment design permits the effect of sun angles to be analyzed independently.</p>

<p>The test took place in 1979.</p>

<p>The supporting docs include a brief summary of used instruments, a wavelength table (Wavelength_ASCII.txt), reflectance note and reflectance tables (ReflectanceTable206.txt and ReflectanceTableMulti.txt), and file format description (ExperimentDataFormat3.txt). The format description file is in ASCII format in lines of 80 characters.</p>

<p>This research dataset is part the Field Research Data Library that consists of over 200,000 spectral observations of soils and vegetation that have been collected since 1972 till 1991 as part of the research focused on vegetation and soils at the Laboratory for Applications of Remote Sensing (LARS) located at the Purdue University.</p>