Deficit irrigation techniques have become more popular over the years as a key practice to improve fruit quality. Before considering this practice, it’s important to understand numerous factors that could impact the outcome of deficit irrigation. Today we’ll explore one such variable: salinity.
This is particularly relevant to winegrowers in California, where vineyards are drawing from declining groundwater sources with increased salinity. However, using saline water could have negative impact for vineyard long term productivity. Various reports have stressed the importance of understanding vine’s response to saline water irrigation.
Impacts on vine composition and productivity
Salinity is usually measured by the electrical conductivity of water. Walker et al. found in 1997 that as electrical conductivity of irrigation water increased, both visual leaf burn symptoms and leaf concentration in chlorine increased.
These early results suggest that increased salinity leads to a decline in vine capacity to produce and store carbohydrates later in the season. Consequently, the viability of grapevines would suffer. To capture this effect, it’s important to implement a biomass monitoring solution such as Physiocap.
More recently, a team of Australian researchers led by Degaris and colleagues studied two moderately saline irrigation treatments on potted own-rooted Shiraz and Grenache vines over two seasons. They demonstrated that deficit irrigation techniques in combination with saline irrigation water change the allocation of ions within a grapevine.
When compared against the control, authors found that the more pronounced deficit irrigation regime led to a higher total concentration of Cl- , Na+ , K+ and Ca++ present on a whole vine basis. The most pronounced deficit irrigation treatment also resulted in significantly lower midday leaf water potential.
Counter the effects of saline irrigation
Does this mean that one should avoid saline irrigation?
In 2013, a team of Australian researchers led by Stevens, researched vineyard floor management practices to reduce levels of sodium present in leaves under saline drip irrigation. The authors found that measures such as removal of under-vine soil mound and rainfall re-direction might be effective in lowering sodium and chlorine concentrations.
In conclusion, saline irrigation might introduce several concerns related to fruit composition, vine nutrient uptake and long-term vine health. Winegrowers need to understand these effects and plan for mitigation measures while considering saline irrigation. Monitoring vine performances throughout the growing season is absolutely critical to ensuring that the selected irrigation scheme works as intended.
Fruition Sciences offers a full suite of products addressing a variety of vine health monitoring needs to enhance fruit and wine quality. Our DualexⓇ Signature product provides detailed nitrogen accumulation profile so that vineyards can apply fertilizer where it’s needed and track adverse effect of saline irrigation on nutrient uptake. Our Physiocap product helps growers identify where dry biomass accumulates in your vineyard to improve pruning decisions. Our Multiplex Ⓡ Map helps vineyards optimize harvesting decisions based on areas of uniform fruit coloration.