Measuring reflectance of soil surface roughness with a field goniometer

This paper will illustrate the effect of soil surface roughness on remote sensing imagery. The agricultural management practice of a field after a crop has been harvested (i.e., bare soils) can leave the surface of the field in one of several different states of roughness. For many precision agriculture applications that utilize remote sensing imagery there is a need for multiple temporal images of a site to determine nutrient prescriptions, stress sources, etc. Imaging the field when it is in the bare soil state Is important for mapping soil zones and determining field drainage. Although the time of day for collecting imagery and the flight lines may be consistent, the bare fields can be a challenging image to interpret due to soil roughness. Since the target may be very non-Lambertian in nature, it must also be recognized that the radiance measured at the sensor will not only have a variation due to moisture and soil texture, but also due. to complex interactions of the electromagnetic energy with a very challenging target surface. This paper will compare differences In view angles for a variety of soil types and roughnesses for data collected at the Mississippi State University agricultural research sites. This data was collected using NASA Stennis Space Center's Sandmeier Field Goniometer.