The influence of regulated deficit irrigation combined with mulching on the vegetative growth of young 'Williams' pear trees

This field experiment was designed to assess the vegetative growth response of young 'Williams' pear trees to regulated deficit irrigation (RDI) and mulching. Using a water budget methodology, four levels of irrigation, specifically 100% of evapotranspiration as control and deficits of 80, 60 and 40%, were applied to 10 trees during the season, 5 of which were mulched with wood chips at a 10 cm layer. The experiment was conducted in Kosovo (Dukagjini Plain) during 2013 and 2014 in a three- to four-year-old pear orchard using a nested experimental design. During the second year of experiment we found significant changes in a series of vegetative growth parameters. Irrigation levels significantly influenced leaf surface area, total leaf area, leaf area index (LAI) and canopy volume, while mulching significantly influenced shoot length and trunk diameter (at the first measurement). RDI and mulching had a combined effect on trunk diameter, number of leaves, leaf area, LAI, number of shoots and canopy volume. Considering the young age of trees and long-term consequences of water stress, the experiment will be continued.