Irrigation of grapevines with saline water at different growth stages. 1. Effects on soil, vegetative growth, and yield

Abstract

Mature field-grown grapevines, Colombard on Ramsey rootstock, grown in a semi-arid climate were irrigated with saline water during any one of 4 growth stages within the season: pre-flowering, during berry development, during berry ripening, and post-harvest. At other times, plots were irrigated with river water (EC 0.5 dS/m) as was the control throughout the season. Saline water (EC 3.5 dS/m) with a high sodium absorption ratio was produced by addition of sodium chloride brine. Soil cation exchange capacity was 14 cmol_c/kg, and at the end of the trial, the soil exchangeable sodium percentage in the control was 6%, in the treatment salinised pre-flowering 13%, during berry development 20%, during berry ripening 20%, and post-harvest 19%. Treatments were applied for 6 consecutive seasons. Vines were highly productive, with the average yield in the control equal to 62 t/ha of grapes. Saline irrigation caused significant, but small, declines in yield in 3 seasons, in pruning weights in 2 seasons, and in berry weights in 4 seasons. Effects on growth, once established, often persisted unchanged through one or more subsequent seasons of saline irrigation. The growth stage shown to be most sensitive to saline irrigation was berry development; saline irrigation during berry development reduced the yield by 7% and during berry ripening by 3%, and pre-flowering it reduced the berry weight by 1%, during berry development by 6%, and during berry ripening by 4%. The amounts of irrigation applied in each of the 4 growth stages were not equal, and hence, treatments did not receive equal additions of salt. Normalising data to remove this effect showed that the rate of yield decline per unit dS/m increase in the seasonal average salinity during berry development, 7%/dS.m, was 3-fold greater than the 2%/dS.m during berry ripening. We conclude that this scion/rootstock combination, grown under these conditions, can maintain high productivity despite ‘slugs’ of saline irrigation.