Interactive effects of frost and effluent irrigation on Grevillea species

Israel is facing severe water restrictions, which led its cut-flower growers to seek alternative water sources for irrigation. These sources include recycled water, treated effluent, and saline water, which all contain relatively high levels of soluble salts. Cut flowers are traditionally considered sensitive to poor quality water, but recent research indicated that they may be more salt-tolerant then was originally considered. Grevillea is used as a cut flower in Israeli agriculture. The response of Grevillea cultivars to irrigation with treated effluent is not known and was evaluated in a field study. Four commercial varieties of Grevillea were studied: ‘Misty Red’, ‘Calundra Gem’, ‘Misty Red’ x ‘Calundra Gem’ (‘Calgem’), and ‘Spiderman’ x ‘Calundra Gem’. The plants were planted in soil or on perlite cushions. The experiment included three water quality treatments: fresh water, secondary treated effluent, and tertiary treated effluent. The quality of the secondary-treated effluent was high and quite sim...