Soil-based automated irrigation for a nectarine orchard in two water availability scenarios

Abstract

This work studies the feasibility of using automated drip irrigation based on the volumetric soil water content measured with capacitance probes in early maturing nectarine trees (Prunus persica L. Batsch, cv. ‘Flariba’) grown in a clay–loam soil in Mediterranean conditions. An automated irrigation treatment (AUTO), based on the management allowed depletion (MAD) concept (with a feed-back control system), was compared with an irrigation-scheduling method based on the conventional crop evapotranspiration (100% ETc) as Control, under high (HWA) and low (LWA) water availability scenarios, each during three consecutive growing seasons. With HWA (no water restriction), the AUTO treatment maintained the soil water content at near field capacity (α = 10% depletion of available soil water content), and there were no significant differences between treatments in terms of the plant–soil water status, nectarine yield, or fruit quality parameters. Under LWA conditions (water deficit), the AUTO treatment (α = 10% during pre-harvest and 30% post-harvest) provided 43% less water than the Control, promoting a moderate plant water deficit, which led to a decrease in vegetative growth (winter pruning and tree canopy cover) but no significant differences in total yield and fruit quality parameters (although the total soluble solid content increased). The water use efficiency values in the AUTO treatment increased by an average of 34%. It was concluded that automated irrigation, based on MAD seasonal threshold values and monitored by means of real-time soil water content sensors, could be considered a promising tool for application in semi-arid Mediterranean agro-systems subjected to water scarcity.