Dissemination of Weed Seeds by Surface Irrigation Water in Western Nebraska
Studies were conducted in 1977 and 1978 to evaluate the impact of surface irrigation water on the dissemination of weed seed in the North Platte River Project from May through September each year. Seventy-seven different plant species were found in irrigation water, with germination averaging 26%. Two to five times more weed seed were found in two irrigation canals than in the North Platte River. As water moved through the canals, the weed seed content of the water increased dramatically. The majority of seed collected was found floating on the water surface. Amounts of seed collected varied with time with the largest amounts being collected in June and July and gradually declining in August and September. Samples also were taken to determine the amount of seed entering the field with irrigation water during the growing season. During the 1978 growing season irrigation water disseminated 48,400 seed per ha in the sampled fields.