Successive cropping of two vegetable crops grown on the same site in one season utilizing trickle irrigation, plastic mulch, and soil fumigation was performed in two separate experiments. In 1980, cabbage (Brassicae olericea L. var capitata cv. Market Prize) was followed by tomato (Lycopersicon esculentum Mill cv. Pik Red). In 1981, cabbage was followed by broccoli (Brassicae oleracea L. var italica cv. Green Duke). Double cropping increased the annual productivity of the research plots both years and decreased production costs by 35% compared to conventional single cropping systems. Early spring planting of the first crop was essential for economic production of the second crop. Trickle irrigation increased yields of all crops grown and was the factor most responsible for yield response both years. Black plastic mulch increased yields of tomato and total yields in 1980 but cole crops showed no significant yield response to mulch either year. No difference in crop yield resulted from soil fumigation either year. Increased production costs have caused growers to seek improved methods to offset risks and costs involved. Trickle irrigation can reduce the risks involved in producing vegetables and is particularly suited to multiple cropping on plastic mulch. / Master of Science