Peach response to water deficit in a semi-arid region

Abstract

A b s t r a c t. During three years a deficit irrigation experiment was performed on peach response under the semi-arid conditions of south-eastern Romania. Three sprinkler-irrigated treatments were investigated: fully irrigated, deficit irrigation treatment, and non-irrigated control treatment. Soil water content ranged between 60 and 76% of the plant available soil water capacity in fully irrigated, between 40 and 62% in deficit irrigation treatment, and between 30 and 45% in control. There were significant differences in fruit yield between the treatments. Irrigation water use efficiency was maximum in deficit irrigation treatment. Fruit yield correlated significantly with irrigation application. Total dry matter content, total solids content and titrable acidity of fruit were significantly different in the irrigated treatments vs. the control. Significant correlation coefficients were found between some fruit chemical components. For the possible future global warming conditions, when water use becomes increasingly restrictive, deficit irrigation will be a reasonable solution for water conservation in regions with similar soil and climate conditions. K e y w o r d s: soil water content, irrigation water use efficiency, fruit yield, fruit quality INTRODUCTIONRegulated deficit irrigation (RDI) and deficit irrigation (DI) have been used in various agriculture experiments. In horticultural crops, such studies were carried out during both pre-harvest and post-harvest stages. RDI assumes imposing moderate reduction in irrigation water amount during some non-critical stages of tree development and preserving fruit yield and quality (Behboudian and Mills, 1997;Chalmers et al., 1981). DI is an optimization strategy in which irrigation is applied during drought-sensitive growth stages of a crop, resulting in plant drought stress, production loss, but maximising irrigation water productivity (English, 1990); DI is actually applied to the whole crop season in both sensitive and non-sensitive periods, but emphasis is put on the first. Some authors have emphasised water relations and plant measurements in fruit growing RDI; for instance, Shackel (2011), working with various fruit trees, reported that the management of irrigation to achieve benefits of RDI is difficult without a reliable plant-based measure of stress, like midday stem water potential, stomatal conductance, vegetative growth, fruit growth and composition, such as soluble solids.The idea of saving water and increasing irrigation efficiency with decreasing irrigation water application was confirmed by English and Raja (1996). Other authors have also reported that in arid regions, irrigation should increase water use efficiency and decrease the impact on the environment, preserving soil and water quality (Dichio et al., 2011). In the short term, DI leads to water saving without yield loss (Fereres and Soriado, 2007;Naor, 2006), while in the long-term fruit yield can be reduced due to the cumulative effects on trees (Intrigliolo et al., 2005). Domingo et al. (2...