Analysis of salt tolerance in nine leafy vegetables irrigated with saline drainage water

Saline agricultural drainage water may be used as a resource to grow high v alue horticultural crops and reduce the volume of drainage for eventual dis posal. To explore reuse options the effects of salinity and timing of appli cation were tested on selected leafy vegetables grown in 24 sand culture pl ots in Riverside, Calif. The leafy winter vegetables included 'Ruby Red Cha rd' Swiss chard [Beta vulgaris L. var. flavescens (Lam,) Lam,],'Space' spin ach (Spinacia oleracea L,), 'Vitamin Green' salad greens [Brassica rapa L, (Narinosa Group)], 'Red Giant' mustard greens [Brassica juncea L, (Czerniak )], pac choi [Brassica rapa L, (Chinensis Group)], 'Winterbor' kale [Brassi ca oleracea L, (Acephala Group)], tatsoi [Brassica rapa L. (Narinosa Group) ], 'Salad King' curly endive (Cichorium endivia L.), and 'Red Preco No. 1' radicchio (Cichorium intybus L,), All vegetables were planted at the same t ime and irrigated initially with tap mater and nutrients, At 3 and 7 weeks after seeding (application times), six salinity treatments were initiated b y adding salts to the irrigation water to represent the chemical compositio ns of drainage waters found typically in the San Joaquin Valley, Calif, The six salinity treatments had electrical conductivities of 3 (control), 7, 1 1, 15, 19, or 23 dS.m(-1). A randomized complete block design was used with (6 salinities x 2 application times x 2 replications). Within each plot a 1.5-m row of each of the nine vegetables was grown as split plots, Salinity reduced fresh weight (FW) yields of all species. Salt stress applied at 3 weeks after seeding reduced FWs for seven of the nine vegetables compared t o salination at 7 weeks. Analyses of salt tolerance curves, maximum yields, and the point of 50% yield reduction (C-50) were conducted. Greens produce d the highest biomass at 874 g/plant, but was the most affected by applicat ion time. Swiss chard and radicchio mere not significantly affected by timi ng of salinity application, and Swiss chard was the most salt tolerant over all. Greens, kale, pac choi, and to a lesser extent, tatsoi, have potential as winter-grown, leafy vegetables in drainage mater reuse systems.