Long-Term Effect of Water Deficit Irrigation on Cherry Vigor and Precocity

Different post-harvest regulated deficit irrigation treatments were established in a young and vigorous commercial 'Bing' cherry (Prunus avium L.) orchard planted in dry shallow soil with drip irrigation. The treatments given over a three-year period were as follows: T-1= 100%, T-2= 75% and T-3= 50% of full ETc. The available water remaining percentage (%AWr) and midday stem water potential (SWP) were measured during the water-deficit period. During the three-year period average SWP was -0.68, -0.83 and -1.04 MPa while % AWr was 89.9, 71.7 and 41.4 for T-1, T-2 and T-3 respectively. SWP was highly correlated with % AWr (r(2)= 0.89). After three years trunk growth decreased by 6% (T-2) and 10% (T-3). Shoot length for T-3 was 27% lower, flower bud density and yield efficiency were 85% and 57% higher when compared to T-1. Seasonal shoot length was highly correlated with flower bud density on productive branches (r(2)= -0.76). Average fruit weight was not affected while double fruits were not substantially affected by treatments. An accurately adjusted post-harvest water deficit can be used to control vigor and promote early production of cherries, while saving significant amounts of water.