Evaluating an automated irrigation control system for site-specific herbigation

Site-specific herbigation using a linear-move irrigation system equipped wi th an automated irrigation control system was evaluated in a series of fiel d trials conducted at the University of Idaho Aberdeen Research and Extensi on Center near Aberdeen, ID. In the first study, the experimental area was divided into site-specific management zones that were randomly assigned her bigation treatments of metolachlor at 0, 1.8, 2.7, or 3.6 kg ai/ha. In a se cond study, site-specific herbigation treatments of metribuzin at 0, 0.28, 0.42, or 0.56 kg ai/ha were applied. The tests covered a range in system fl ow rate from 29 to 90% of maximum design flow. Average metolachlor rates ap plied were within 1, 2, and 4% of the target 1.8, 2.71 and 3.6 kg/ha rates, respectively and average metribuzin rates were on target at the 0.28 kg/ha rate and within 5 and 2% of the 0.42 and 0.56 kg/ha target rates, respecti vely. In a third study, potato (Solanum tuberosum) fields were divided into management zones, and low, medium, or high populations of Indian mustard ( Brassica juncea) and foxtail millet (Setaria italica) were seeded in each z one. Different rates of a metolachlor plus metribuzin mixture were herbigat ed in each zone-higher rates in zones with high populations and lower rates in zones with low populations. Weed control was excellent in all zones. Re sults suggest good potential for site-specific herbigation when linear-move or center-pivot irrigation systems are equipped with the automated irrigat ion control system.