PARTIAL ROOTZONE IRRIGATION OF ‘GOLDEN DELICIOUS’ APPLE TREES IN A SEMI-ARID ENVIRONMENT

Abstract

Water for irrigation is a limited and expensive resource for apple (Malus pumila Mill.) production in the semi-arid zones of the world, i.e., the Northern region of México where 44 thousand hectares are under apple cultivation. Partial rootzone drying (RPR) is a watersaving irrigation technique which has been successfully tested in apple trees cultivated in humid areas, but it has not been evaluated yet in semi-arid areas. The objective of this study was to determine the impact of RPR on yield and fruit quality of ‘Golden Delicious’ apple trees grown in a semi-arid climate where crop evapotranspiration is higher than in a humid area. Treatments were: full irrigation (RC, control) and RPR; in the latter treatment 50 % of water in RC was given in each irrigation turn. In RPR, irrigation was alternatively given from the wetted side to the drying side of the root system every 8 d or when soil water content reached a threshold of soil water depletion. In general, yield and yield components were statistically similar between treatments, but the water use efficiency was significantly improved in RPR trees by 70 % in relation to RC trees. The RPR saved water by 44 %. Mean weight, flesh firmness, and total soluble solids concentration of the fruit were statistically the same between treatments. Fruit dry matter concentration was higher in RPR trees than in RC trees. The RPR deserves to be validated in other apple cultivars and in other agro-ecological environments before this technique could be commercially spread out.