Variable rate irrigation in a vineyard and an orchard

Due to climate changes and frequent water-limited conditions, high efficiency in water use is necessary to support crop growth. One promising strategy to enhance water management is represented by precision irrigation, which allows optimization of water distribution by considering the within-field variability. The aim of the present study was to compare the variable rate drip-irrigation system (VRDI) with a traditional drip-irrigation system (DI) in two case studies. The experiment took place in 2018 in a pilot vineyard and pear orchard located in Lombardy (Italy). Within-field variability was detected by soil electrical conductivity and two homogeneous zones were defined by statistical clustering. Soil profiles were characterized in each homogeneous zone. In each field, a VRDI system was designed defining two sectors according to the soil zones, optimizing in each sector the flow rate and the distance between drippers. In both fields, a transversal sector was managed according to the typical DI system as reference. During the season, precipitation, soil moisture, and irrigation water were monitored. At harvest, pear and grape productions were registered, as well as sugar content, pH, titratable acidity and pear firmness. During the experimental year, the amount of irrigation water for VRDI respect to the DI system was reduced by 20% in the vineyard and by about 50% in the pear orchard. No significant differences between the two systems were found in the production of grape and pear and minor differences were found in fruit quality parameters. This study shows that using a VRDI system is possible to reduce irrigation water, maintaining production and quality in vineyards and pear orchards.