DETERMINING THE POTENTIAL FOR SILICON TO MITIGATE DROUGHT STRESS IN FLORICULTURAL CROPS USING SLAG AS A SILICON SOURCE
Application Technology Research Unit
Project Number: 3607-21000-015-32
Start Date: Jul 15, 2012
End Date: Sep 30, 2014
Water stress is a common occurance in greenhouse production due to failures of automatic irrigation systems, lack of labor to hand water, and unexpected changes in weather conditions. Certain crops such as garden chrysanthemums require copious water during production, while others like zinnia and New Guinea impatiens do not tolerate even mild drought conditions, resulting in dessication or loss of leaves. The element silicon (Si) is reported to mitigate water stress in many field crops, but the extent of its beneficial effects are not known for floricultural crops. We plan to test the effects of supplemental silicon nutrition of the aforementioned crops' ability to withstand drought stress. Furthermore, we will compare reagent-grade silicon, from potassium silicate, to a less expensive source of silicon from slag. Finally, we will test the plant material tissue for amounts of Si as well as other essential elements and heavy metals to determine if any metal is leaching from the slag and being taken up by the plants.
ARS will grow three crops (garden chrysanthemums, zinnia, and New Guinea impatiens) in soilless media and hydroponics with and without supplemental Si in two forms (reagent grade potassium silicate and slag), induce water stress either by withholding water in soilless media or adding salt in hydroponics, and monitor how quickly plants succumb to water stress. Plants will then be rewatered or switched to salt-free nutrient solutions to monitor their recovery. At harvest, plant tissue will be separated into roots, stems, and leaves, dried, and analyzed for Si, essential elements, and heavy metals using our in-house nutrient analysis equipment. In parallel with this research, a colleague at Utah State University will be doing similar work investigating drought effects on corn, soybean, rice, and wheat, and evaluating the potential benefit of silicon in mitigating that stress.