Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 1997
Publication Date: N/A
Interpretive Summary: Effective irrigation management to achieve optimum yield is essential to commercializing Lesquerella fendleri, a promising new oilseed crop containing a large amount of a unique oil used in a variety of industrial and consumer products. However, information on lesquerella's water requirement and yield responses to irrigation is limited. Irrigation studies conducted for two years in central Arizona quantified how much water is required for lesquerella during the season. Irrigation management recommendations for successful lesquerella production in the arid Southwest are also presented. This research provides new information on lesquerella that will be beneficial to growers in guiding their irrigation water management practices of this crop.
Technical Abstract: Detailed irrigation studies were conducted with Lesquerella fendleri (Gray) Wats. in Arizona during the 1991-92 and 1992-93, fall-spring seasons to determine its water requirement and yield. In 1991-92, the highest dry matter yield was obtained for a control irrigation treatment with seven post-emergence irrigations. Four limited water treatments were given either three or four irrigations and yielded 26 to 36% less dry matter than the control. Total ET for the control was 634 mm, whereas ET for the limited water treatments varied from 460 to 500 mm. Total seed yield in 1991-92 was not determined. In 1992-93, lesquerella was grown under eight irrigation treatments: weekly (W; 12 post-emergence irrigations), biweekly (B; 7), weekly with two supplemental irrigations in early winter (WS; 14), biweekly with two supplemental irrigations in early winter (BS; 9), and four treatments that were irrigated the same as Treatment B, except that irrigation was withheld during early flowering (B1; 5), withheld during mid-flowering (B2; 6), withheld at full bloom (B3; 6), and withheld during seed formation/ripening (B4; 5). Irrigation treatments affected both the dry matter yield and seed yield. Withholding irrigation on the biweekly application during mid-flower and during seed formation/ripening resulted in the lowest seed yields. The BS treatment had the highest dry matter (7020 kg/ha) and seed yield (888 kg/ha), suggesting a possible yield benefit from the early winter irrigations. Total ET for treatments varied from 535 to 767 mm. Total ET corresponding to the maximum yield was 668 mm. A water management that allows about a 50% depletion of the available soil water from the onset of flowering through seed ripening can result in maximum growth and yield. Providing irrigation every 14 days during this