THE IMPACTS OF TRANSITION FROM FLOOD IRRIGATION TO DRIP IRRIGATION METHOD ON PLANT WATER CONSUMPTION AND YIELD IN APPLE GROWING

摘要

This study elucidates the effects of transition from flood irrigation to drip irrigation method on apple trees regarding the water consumption and yield of the plant in 2008 and 2009. Starkrimson Delicious variety grafted onto seedling rootstock was used in the study. The studied apple trees had been irrigated by flood irrigation for many years. During the study, flood irrigation was continued at one part of the orchard, and drip irrigation was applied with different irrigation programs at the remaining parts of the orchard. Irrigation interval was held 20 days for flood irrigation (conventional) method. For drip irrigation, two different irrigation intervals (I =4 days, 1=1 days) and four different pan coefficients (K_(cp1)=0.50, K_(cp2)=0.75, K_(cp3)=1.0, K_(cp4)=1.25) were used in the study. The highest amounts of irrigation water and plant water consumptions were determined for flood irrigation treatment for both years. Expanding the irrigation interval and increasing the pan coefficient led toan increase in plant water consumption during drip irrigation treatments. The highest amount of plant water consumption was determined in IjK_(cp4) treatment. Statistically, while the yield with flood irrigation treatment was higher than K_(cpl) and K_(cp2) treatment, the yield data of K_(cp3) and K_(cp4) treatments were similar in both years. Irrigation levels (K_(cp)) influenced the yield (p < 0.01); however, irrigation intervals and irrigation intervals x irrigation level interaction did not have any impact on the yield. Kcp_3 and Kcp_4 (1.25) represented a more marketable fruit size (extra and class 1) than flood irrigation. As a result, during the application of drip irrigation for the apple trees, which were previously irrigated, by flood irrigation for many years, the irrigation interval and pan coefficient (K_(cp)) under similar climatic and soil conditions were considered as 4 days and 1.0, respectively.