Effects of the implementation of the Alternate Wetting and Drying (AWD) irrigation strategy in an Italian rice district: lesson learned by applying a semi-distributed agro-hydrological model
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Data di Pubblicazione:
2022
Citazione:
Effects of the implementation of the Alternate Wetting and Drying (AWD) irrigation strategy in an Italian rice district: lesson learned by applying a semi-distributed agro-hydrological model / G. Gilardi, A. Mayer, M. Rienzner, G. Ottaiano, M. Romani, E. Cadei, O. Gharsallah, A. Facchi. ((Intervento presentato al convegno Interregional Conference Sustainable Production in Agroecosystems with Water Scarcity tenutosi a Albacete nel 2022.
Abstract:
The north-western part of the Padana Plain in northern Italy is the most important rice district in Europe and
the second in the Mediterranean basin after Egypt (230,000 ha in Italy and 450,000 ha in Egypt). Traditionally,
rice irrigation was based on wet seeding and continuous flooding until to approximately three weeks before
harvesting. Recently, due to an increased frequency of water scarcity periods and competition for water
among agricultural and non-agricultural uses, water saving techniques are being introduced. Although these
techniques must be firstly tested on a field scale, it is important to estimate their effects on the overall water
resources system. In fact, especially in rice areas characterized by shallow aquifers, the strong interaction
between traditional irrigation methods and phreatic aquifer levels leads to a re-use of the irrigation water
which contributes to water flows in rivers and irrigation networks thus increasing the overall irrigation
efficiency of rice areas.
An experimental platform was set up in the core of the Italian rice area (Castello D’Agogna, PV) to compare
three rice irrigation management strategies over two agricultural years (2019-2020): wet seeding and
traditional flooding (WFL), dry seeding and delayed flooding (DFL), and a ‘safe’ wet seeding and alternated
wetting and drying irrigation (AWD-safe). Irrigation water use was monitored by the installation of flow
meters, and all the other soil water balance components were quantified. At the field scale, water savings of
AWD and DFL were found to be about 20% and 14% compared to WFL without penalizing rice production,
while the temporal distribution of irrigation water needs and percolation fluxes changed as a function of the
irrigation strategy.
Results achieved in the experimental fields were used in the parametrization of a semi-distributed and
physically-based agro-hydrological model aimed at stimulating the overall irrigation system efficiency of a
rice district (about 1000 ha) located close to the experimental platform. The modelling framework consists
of three sub-models: i) one for the agricultural area, based on the physically-based SWAP model; ii) one for
the channel network percolation; iii) one for the groundwater level dynamics. After investigating the current
water dynamics and irrigation system efficiency for the period 2013-2020, the modelling system was used to
explore the effects on the water resources system of some ‘what-if scenarios’, such as the adoption of a
AWD-safe rice irrigation strategy in the whole district. The AWD-safe technique after wet seeding seems to
be a good compromise solution in terms of recharging groundwater and reducing the peak irrigation request
for rice.
This research was developed in the context of the MEDWATERICE (PRIMA-Section2 2018;
https://www.medwaterice.org/) project.
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Keywords:
irrigation district; rice irrigation requirement; water-saving technology; agro-hydrological model; groundwater level; irrigation network efficiency
Elenco autori:
G. Gilardi, A. Mayer, M. Rienzner, G. Ottaiano, M. Romani, E. Cadei, O. Gharsallah, A. Facchi
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