A 3-year irrigation scheduling study on carrots (Daucus carota L.) was conducted at the Colorado State Univ. Horticulture Research Center near Fort Collins to determine the irrigation schedule that produced the best combination of high water use efficiency and marketable yields with the least amount of water and fewest irrigations. This study used an irrigation scheduling program developed by the U.S. Department of Agriculture/Agricultural Research Service with crop coefficients calculated for carrots. Maximum carrot production and water use efficiency were obtained when the scheduling program simulated a 30-cm rooting depth at planting, increasing linearly to 60 cm in 75 days. Best yields and water use efficiency were attained by irrigating whenever 40% of the available water in the root zone had been depleted. The computer program for irrigation scheduling is available on diskette from the authors.
Abstract
Cucumber (Cucumis sativus L.) irrigation scheduling was studied during the 4 years of 1983-1986. Tensiometers were used during the first year to determine when to irrigate, and the USDA irrigation scheduling program was used to determine the amount of water to apply. The data from the first year’s study indicated that the plants had not been stressed; therefore, the following year, estimates of the available water depletion were made with the USDA irrigation scheduling program, with tensiometers used only for comparison. After 4 years of study, we concluded that the best combination of high yield, high water use efficiency, and fewest number of irrigations was obtained if cucumbers were irrigated when the original scheduling program determined that 40% of the available water was depleted, applying only 70% of the water that the program indicated was required. This signaled that the program was overestimating the rate at which water was being depleted. Therefore, as a final step, a revised set of cucumber coefficients that approximated daily evapotranspiration (ET) more closely was determined. When using the revised coefficients, cucumbers should receive the exact amount of water called for by the irrigation program.
issues ( Cahn et al., 2014 ). A need exists for low-cost management strategies including use of irrigation scheduling technologies that incorporate information on meteorological conditions and crop growth stage. The CIMIS, operated by the California
plant functions and, if applied correctly, above which there is no added benefit to the plant ( Gilman et al., 1998 ). This implies that once that volume of water is applied, adding more can be wasteful. Scheduling landscape irrigation based primarily on
, and the ability to electronically schedule irrigation on large areas with smaller pumps relative to sprinkler systems. If microsprinkler systems are operated under windy conditions on hot, dry days, wind drift and evaporation losses can be high. Thus
irrigation water while contributing to crop return by 39%. Irrigation scheduling is important in vegetable production. Under-irrigation generally results in yield loss and low produce quality. Conversely, overirrigation increases the crop's susceptibility to
Optimal irrigation scheduling could lead to higher water use efficiency, an objective of very high importance nowadays. Adequate supply of water and nutrients results in higher water and nutrient use efficiency, better production control, and
Irrigation scheduling is a process by which the timing and amount of water applied are determined to meet the evapotranspiration demands of the crop. Both the water delivery system and the availability of water to the plant need to be considered in
( Warren and Bilderback, 2005 ). Efficiency of spray-stake irrigation can be improved by using a cyclic irrigation schedule that applies water multiple times per day vs. a single application ( Beeson and Haydu, 1995 ; Ruter, 1998 ). Producing plants in
; C) 12, 18, 22, and 26 weeks after sowing; and D) 14, 19, 23, and 27 weeks after sowing. Figure 1 illustrates the sowing and harvesting schedules. By early May in each year of the study, cabbage aphids ( Brevicoryne brassicae ) had infested a