A sustainable irrigation based on a soil water balance model for the production of Carpinus betulus L.

Until recently, it was possible to produce high-quality avenue trees through rain-fed methods. However, due to recent prolonged drought periods during the growing season, the growth and quality of the trees are impacted, leading to a lower economic value. Therefore, the tree nursery sector requires irrigation thresholds and appropriate tools such as plant and soil sensors to schedule irrigation according to crop water needs. In 2022 and 2023, a trial was performed on 3- and 4-year-old hornbeam avenue trees (Carpinus betulus L.), in which a rain-fed treatment was compared with a drip-irrigated treatment. Irrigation doses were determined according to a calibrated soil water balance model, based on reference crop evapotranspiration rainfall, and soil hydraulic properties. In 2022, irrigation was mostly applied during the dry months of July and August. Although the effect of irrigation on soil moisture was less straightforward, it had a positive effect on stem water potential. In 2023, the trees were only irrigated during the dry month of June. This had a positive effect on both the soil and the stem water potential. During both years, irrigation had a positive effect on stem growth resulting in a higher economic value.