Response to regulated deficit irrigation of a nectarine orchard in Southern Spain

Abstract

Irrigated agriculture is facing restrictions due to water scarcity. Regulated deficit irrigation (RDI) is a technique that has been shown to reduce irrigation water use in fruit orchards and vines. In RDI, water is applied below crop requirements during certain developmental stages that are less sensitive to water stress. The objective of this study was to test the RDI strategy in a nectarine commercial orchard (Prunus persica (L.) Batsch ‘Sweet Lady’) in Southern Spain. The experiment was conducted in 2007 and 2008 and RDI was compared to the farmer’s irrigation schedule. In RDI treatment, water was withheld from the start of the irrigation period (end of May) until the start of the rapid fruit growth period (stage III). The strategy was to recover, as fast as possible, the water status of trees in order to avoid any water stress during stage III. Neither yield nor any measured parameter was altered by the RDI relative to the farmer’s irrigation schedule. In 2008, yield was slightly increased compared to 2007. There was a good relationship between the stem water potential during stage III, fruit volume, and total soluble sugars. These results demonstrate that water deficit must be avoided during this very sensitive period if the goal is to achieve large fruit size.