Grapevine recovery from saline irrigation was incomplete after four seasons of non-saline irrigation

Abstract

Crop exposure to salinity can be episodic. The effects on the crop are the sum of those manifest whilst stress establishes, persists and abates. This paper reports on the response of grapevines during stress abatement. It follows from Stevens et al. (2011a) which reported on the response over three consecutive seasons of Colombard vines (Vitis vinifera) on Ramsey rootstock (Vitis champinii) to irrigation with saline water (ECi 3.5dS/m) during specific growth stages, and with non-saline water (ECi 0.5dS/m) during the rest of the season. Over the next four seasons all vines were irrigated with non-saline water (ECi 0.4dS/m). The current paper characterises recovery during this period using key traits including growth, yield and concentrations of Na+ and Cl− in root and leaf lamina. By harvest in the second season following cessation of saline irrigation, the soil salinity and leaf lamina Na+ and Cl− concentrations in previously salinised vines had fallen below the levels associated with salinity-induced yield loss. Maximum yield loss of 22% averaged over the four seasons was higher than the maximum of 15% during saline irrigation. Yield losses were associated with loss of berry weight. Following cessation of saline irrigation, a reduction in bunch numbers caused an additional yield loss. A reduction in pruning weights did not emerge until after saline irrigation ceased. Salinity's sting can be in its tail. Losses of yield, bunch number and pruning weight were independent of season, whilst those in berry weights diminished over the four seasons. In the last two seasons, yield loss could not be attributed to osmotic or toxic effects of salinity. Another unidentified effect of salinity was stressing the vines.