The influence of physical soil properties on the water supply of irrigated orchards-some examples from Val Venosta (South Tyrol/Northern Italy)

In irrigated agriculture, irrigation water volume and duration of irrigation can be optimized utilizing soil water dynamics data. Val Venosta in South Tyrol (Northern Italy) is a region where irrigation represents a central factor of production in the Tyrolese fruit-growing areas. Intensive orchard production is practised within an area of about 18.000 ha. Although fruit cultivation experts believe that intensive fruit cultivation should be based on regular irrigation of the fruit trees to guarantee optimum results in both fruit quantity and quality; however, fruit growers in the region follow very subjective criteria in regard to irrigation. At many locations much more water is used than the fruit trees actually need. Therefore irrigation in this region is a very cost-intensive factor of production and is criticized by the public for both economic and ecological reasons. To optimize the irrigation practice in this region it is essential to provide an objective basis for the irrigation process. A system of "precision irrigation" proposed, which is therefore based on objective and quantitative criteria focusing primarily on soil properties and hydrologic balance. This contribution will provide an overview of the current situation of irrigation and present results from soil-physical and soil-hydrological studies performed in this region since 2003.