Irrigation Factor Approach Based on Soil Water Content: A Nectarine Orchard Case Study

Abstract

Precision agriculture requires irrigation supported by an accurate knowledge of the crop water requirements. In this paper, a novel approach for drip irrigation scheduling of fruit trees is presented based on the results obtained during a full growing season in an early-maturing nectarine orchard growing in a clay loam soil in a Mediterranean environment. Real-time water content was monitored in the soil profile of the main root exploration zone by means of capacitance probes; in addition, plant water status (midday stem water potential and leaf gas exchange) and canopy development were frequently measured throughout the vegetative cycle. The reference evapotranspiration (ET0) values, taken from a nearby automatic meteorological station, and the measured irrigation values allowed the determination of the irrigation factors once irrigation drainage during the season was assumed to be negligible and plant water status was proved to be adequate. The proposed irrigation factors offer a hands-on approach as an easy tool for irrigation management based on suitable soil water deficits, allowing the water requirements of nectarine trees under precision irrigation to be determined in semi-arid agrosystems where water resources are limited.