AgIIS, Agricultural Irrigation Imaging System

Abstract

Ground-based remote sensing can provide data at spatial resolutions, repeat frequencies, and turnaround times that are suitable for daily farm management at the field scale, whereas present satellite and airborne platforms do not meet these criteria. Remotely sensed data, when combined with other ancillary data, can provide spatially distributed maps of vegetation vigor, evapotranspiration, crop water stress, and nitrogen status. The objective of this paper was to describe the design, operation, and data processing of a ground-based remote sensing system called the Agricultural Irrigation Imaging System (AgIIS) that uses a self-propelled lateral move irrigation system as the transport platform. AgIIS consists of a cart that contains four nadir-looking sensors that measure reflected irradiance in the green (555 nm), red (670 nm), red-edge (720 nm), and near infrared (790 nm), all filtered to a 10-nm band pass at the band centers, and an infrared thermometer that measures directional radiometric surface temperature. The cart moves along a track, which is mounted to the overhead pipe of the lateral move system. Surface reflectance and temperature measurements were resampled to 1- m x 1-m raster grids, which were used to construct maps of vegetation, water, and nitrogen stress indices. These indices were correlated to field measurements of leaf area index, (r2 = 0.81 to 0.92), soil water deficit index (r2 = 0.76 to 0.86), and leaf petiole nitrogen content (r2 = 0.17 to 0.55), where experimental treatments consisted of two rates of irrigation and nitrogen applications for a cotton and broccoli crop.