Effect of three different irrigation regimes on young apricot (Prunus armeniaca L. Batsch) trees

Abstract

SummaryThe effects of three different irrigation regimes were compared in an apricot (Prunus armeniaca L. Batsch,‘Bergeron’) orchard over 5 years from the time of planting. The regimes were based on measuring crop evapotranspiration (ETc), or by tensiometric or dendrometric scheduling methods. Under the dendrometric method, the threshold for irrigation, based on trunk growth rate (TGR) and maximum daily shrinkage (MDS), was assessed over the first 3 years, then modified in the last 2 years according to the results obtained. Compared to ETc or tensiometric methods, the dendrometric method led to considerable reductions in the amount of water applied over the 5 years of the experiment (by 66% and 54%, respectively), without significantly affecting fruit yields or average fruit weights. Total soluble solids contents tended to be higher, and the extent of the red colour of the peel was higher under the dendrometric method than under the ETc or tensiometric methods. The trunk cross-sectional areas (TCSA) of apricot trees were reduced under the dendrometric method compared to the ETc or tensiometric methods, but only during year-3 of the experiment. During year-4, TCSA values tended to recover when applying the same amount of water under the dendrometric method as under the ETc method. The incidence of pitburn was lower under the dendrometric method than under the ETc or tensiometric methods, and appeared to be correlated with the percentage of the total water applied before fruit ripening. The restricted application of water was assumed to have had an impact on the incidence of pitburn by improving calcium concentrations in apricot fruit. Restricting irrigation from the time of planting is therefore not only a relevant strategy to conserve water, but also to improve fruit quality in an apricot orchard.