Effects of wetted soil percentage on the growth and water use of mature Korla fragrant pear trees under drip irrigation

The wetted soil percentages included 3 levels(20%,40% and 60%) and the traditional flood irrigation(100% of wetted percentage) was used as control.Soil water potential in the root zone was monitored by a tensionmeter and gypsum blocks.The growth indices of fruit trees were recorded at different growth stages.The daily water use,crop coefficients and pan coefficients under different drip irrigation treatments were estimated by water balance method.The results indicated that the tree water uses under wetted percentage of 20%,40% and 60% decreased by 69.11%,63.91% and 55.05% respectively as compared with that under flood irrigation,while the shoot growth reduced slightly,by 9%,5% and 3%.Compared with flood irrigation,the fruit volumes under drip irrigation treatments of different wetted percentage were all bigger,with the largest under 40% treatment.Moreover,the fruit quality under drip irrigation treatments was improved to certain extent.It is suggested that at the transient stage of flood irrigation into drip irrigation,a wetted percentage of 40% should be used.This study should be meaningful to drip irrigation system design and management.