ECONOMIC RESPONSES OF BROCCOLI AND CAULIFLOWER TO WATER AND NITROGEN IN THE DESERT

Field studies were conducted to develop water and N response surface m odels for broccoli and cauliflower (Brassica oleracea L., Botrytis Gro up) produced in the low desert of the southwestern United States and t o estimate profit maximizing combinations of water and N over a range of realistic price situations. Marketable broccoli and cauliflower yie lds were increased by water and N inputs in all experiments. Generaliz ed response equations indicate maximum broccoli yields with 43 cm of w ater and N at 267 kg . ha(-1) and maximum cauliflower yields with 65 c m of water and N at 338 kg . ha(-1). Least-cost combinations of water and N changed with the costs of these inputs for yield levels below th e economic maximum. However, profit maximizing N and water rates chang ed little regardless of input or crop prices investigated.