RESPONSE OF ORNAMENTAL SUNFLOWER TO IRRIGATION WITH SALINE WASTEWATERS

Authors: Grieve, Catherine; Poss, James

Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2005
Publication Date: 7/1/2005
Citation: Grieve, C.M., Poss, J.A. 2005. Response of ornamental sunflower to irrigation with saline wastewaters. American Society for Horticultural Science, Annual Meeting, Las Vegas, NV. July 18-21, 2005. CD-ROM. 40(4):1084.

Interpretive Summary:

Technical Abstract: Competition between agricultural and urban users for high-quality water supplies has increased as the population has increased. One environmentally-sound approach to the conservation of these dwindling water resources is the reuse of degraded, often saline, wastewaters for crop production. Growers of high value cut flower crops have traditionally used high-quality waters in order to avoid yield losses associated with salinity. However, little quantitative information is available in the literature that would guide growers in the selection of cut flower species which could be produced with recycled, saline waters. This report describes the response of two commercially valuable cut flower species to irrigation with saline waters differing in ion composition. Solutions were prepared to simulate saline drainage effluents commonly present in two inland valley regions of California: (1) the San Joaquin Valley and (2) the Coachella Valley. Two varieties of ornamental sunflower, ‘Sunbeam’ and ‘Moonbright’ were grown in greenhouse sand tanks. Five salinity levels were imposed with electrical conductivities of 2.5, 5, 10, 15, and 20 dS m-1. Flower diameter was not reduced by salinity. Length of the flowering stems declined from about 5' to 3' as salinity increased. Since growth regulators are often used to control excessive stem length in sunflower, the application of salinity would reduce costs of sunflower production by avoiding the use of chemical growth inhibitors. Both cultivars proved to be moderately salt tolerant. The enhanced ability of sunflower to withstand the challenge of salt stress appeared to be associated with its ability to exclude potentially toxic concentrations of sodium from leaf tissue. From this greenhouse study, we conclude that moderately saline irrigation waters can be used in the production of ornamental sunflower, thus conserving significant quantities of high quality waters.