ARS | Publication request: GROWTH RESPONSE AND SELENIUM AND BORON DISTRIBUTION IN BROCCOLI VARIETIES IRRIGATED WITH POOR QUALITY WATER.

Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2003
Publication Date: May 16, 2003
Citation: Banuelos, G. S. Pasakdee, J.W. Finley. Journal of Plant Nutrition. 2003. 26:2537-2549.

Interpretive Summary: There is an increasing trend in using poor quality water for irrigated agriculture in central California. The suitability of poor quality water for irrigation is dependent on the crops' tolerance to salinity and the concentrations of selenium and boron. Growing a high cash value crop like broccoli that tolerates salt, boron, and selenium would likely be a preferred choice by growers using water of poor quality. In this greenhouse study the salt tolerance and selenium and boron distribution was assessed in different varieties of boroccoli that were irrigated with water of different qualities. For all varieties, there was little effect on the yields of the marketable product - florets. Selenium accumulation was greatest in the florets and boron and chloride concentrations were greatest in the leaves. The results indicate that the tested broccoli varieties should be considered as recipients of moderately saline water with selenium and boron under field conditions. Even though broccoli is a short season crop, salt and boron management will eventually be needed for the soils irrigated over time.

Technical Abstract: Many drainage waters can be used successfully to grow selected crops without long-term consequences to crops and soils. Certain ions in saline waters can be specifically toxic to plants, if they accumulate to toxic concentrations within the plants tissues. Of particular concern in the San Joaquin Valley of California are selenium (Se), boron (B), and Chloride (Cl). In this greenhouse study, we evaluated Se, B, and Cl accumulation in different broccoli varieties irrigated with moderately-saline water containing salts, Se, and B. Treatments consisted of: 1) non-saline water; 2) Cl/sulfate saline water (5ds/m), 250 ug Se/L, and 5 mg B/L; and 3) non-saline water and 250 ug Se/L. Floret yields were generally insensitive to water quality treatments. For all varieties, plant Se concentrations were greatest in the floret (up to 5 l mg/Kg DW, while B and Cl concentrations were greatest in the leaves; 110 mg B/Kg DW and 5.4 percent Cl, respectively. At postharvest soils from treatment 2 had a soil salintiy of 6 dS/m, a total Se concentrations of 0.6 mg/Kg DW, and soluble B concentration of 2.3 mg B/L. Although broccoli is a short season crop, the increased soil salintiy and B indicate that salt and B management may be necessary for soils receiving this quality of water under field conditions.