Use of a virtual-reference concept to interpret active crop canopy sensor data

摘要: Active crop canopy sensors make possible in-season fertilizer nitrogen (N) applications by using the as a bio-indicator of vigor and N status. However, sensor calibration is difficult early in growing season when crops are rapidly growing. Studies were conducted United States Mexico to evaluate procedures determine vegetation index adequately fertilized plants producer fields without establishing nitrogen-rich reference area. The virtual-reference concept uses histogram characterize display data from which can be identified. Corn at five-leaf growth stage was used opportunities for variable rate application conventional tractor-based equipment. A field Nebraska, USA twelve-leaf compare interpretation strategies using: (1) virtual where determined before initiated; (2) drive-and-apply approach (no prior information initiating application) flow-rate control system continuously updates automatically calculates plants. 95-percentile value vegetation-index This calculate sufficiency other fields. analyzed an N-rich 3-5 % lower than derived concept.