CULTURAL PRACTICES TO REDUCE SALINITY/SODIUM DAMAGE OF RABBITEYE BLUEBERRY PLANTS (VACCINIUM ASHEI READE)

Blueberries are very sensitive to irrigation water which contains high salt, HCO₃, or sodium levels. A series of experiments were conducted to determine cultural practices that would maximize plant performance with poor quality irrigation water. Cultivar screening: 'Delite' and 'Brightwell' were more salt tolerant cultivars than 'Tifblue', 'Premier' and 'Climax'. Water modification: Irrigation water (electrical conductivity=0.7 dS.M^-1, pH=8.7, SAR=30) which had been modified with the addition of gypsum or acid, did not improve plant performance. Mulch and irrigation geometry: Drip emitters at the plant base and/ or mulch markedly reduced salt accumulation in the rootzone. Micro-sprinklers resulted in better overall plant performance than drip emitters. Soil modification: Preliminary results with pre-plant gypsum incorporation in the field or the use of high Ca rates in solution culture to ameliorate Na damage indicated no harmful effect up to 200 g gypsum per planting hole (10 kg/M³) or up to 10 mM Ca in solution. Calcium at 1 and 3 mM partially reduced Na damage.