Effect of irrigation on Sant’Erasmo violet artichoke production: preliminary assessments

The violet artichoke is a typical horticultural product of the Venice Lagoon (Italy). In this area, the artichoke is not normally irrigated but, due to rising temperatures and increasingly prolonged periods of drought, linked to ongoing climate change, farmers are considering introducing irrigation, also to counteract excessive rising of brackish water. A test was carried out in 2021 in a plot of a farm located in Sant’Erasmo island (site that also names the product), in two distinct periods: a first period, from April 20 to June 7, to assess the influence of irrigation on the production of buds, and a second period, after summer vegetative recovery, from August 20 to December 15, to analyse the influence on the production of leaves (thistles or cardoons). The plot was divided in three theses: irrigated with a single drip line, irrigated with a double drip line, and no irrigated (control). Irrigation volumes were calculated using a simplified water balance based on crop evapotranspiration ETc (estimated using the FAO method) and daily rainfall data recorded by a nearby weather station. The results of the first period were influenced by heavy and frequent rainfall which did not allow to assess the effect of irrigation. In the second period, which followed a long and droughty summer, results showed significant differences, with a higher production in terms of quantity of biomass harvested (total and marketable) in the irrigated thesis. In addition, the number of shoots and the plant heights showed statistically significant differences between single-line and double-line drip irrigation systems, with the former probably benefiting from a water supply closer to the rhizome, also proving to be the better solution in terms of functionality, irrigation efficiency and cost.