Long-term effects of restricted root volume and regulated deficit irrigation on peach: II. Productivity and water use.

摘要

Individual and interactive effects of restricted root volume (RRV) and regulated deficit irrigation (RDI) on productivity and water use of peach trees (cv. Golden Queen) were studied over 3 years (1992-95). Trees were grown in lysimeters of five different soil volumes (0.025, 0.06, 0.15, 0.4 and 1.0 m3) with either full or deficit (RDI) irrigation. In years 3 and 4, fruit size was reduced by up to 30% on trees in the two smallest volumes. Tree water use was positively related to increasing soil volume in all years ranging from 1.8 to 4.4 litres/mm Epan in the post-RDI period of year 2. Water use of deficit-irrigated trees was less than that of fully irrigated trees and there was an interaction between soil volume and irrigation treatment during RDI. Water relations did not limit growth or productivity. Tree water use was reduced under root restriction as a consequence of canopy demand rather than leaf function. Results suggest that a combination of restricted root volume and development of waterstress achieve the required RDI response in the Goulburn Valley, Australia.