Climate change, effective water use for irrigation and adaptability of maize: A case study in southern Italy

• Different irrigation schedules simulated for maize in a reference and future climate.
• Hybrid biodiversity and effect on requirement for water availability examined.
• The impact of climate change on irrigation requirements was evaluated.
• Soil physical properties were important in the assessment of maize adaptability.
• A proper choice of hybrids and soils may allow water savings in future climate.

Climate change may lead to differences in the distribution of precipitation and to reduced water availability, with constraints on the cultivation of some crops. An analysis of vulnerability and of opportunities for adaptation is required for crops in areas where they are currently cultivated. The intra-specific biodiversity of crops is a significant resource for the adaptation of agriculture, but requires better knowledge of the responses of cultivars to environmental stressors. Simulation models of water flow in the soil-plant-atmosphere system can be coupled with future climate scenarios to describe the soil water regime, taking into account different irrigation scheduling options. The adaptive capacity of maize hybrids is evaluated in an irrigated district in Southern Italy. Two climate cases were studied: “reference” (1961–1990) and “future” (2021–2050). The model SWAP was run to determine the soil water balance for different irrigation levels. For each level the effectiveness of irrigation was evaluated by means of a performance indicator (IE). The Relative Evapotranspiration Deficit (RETD) was used as an indicator of water availability. The yield response to water availability of several maize hybrids was determined; their hydrologic requirements were thus defined and compared with the simulated values of RETD in response to climate and irrigation. Soil moisture regime and irrigation performance were also analysed. The adaptability of hybrids to the future water regime was assessed for different irrigation levels. The study indicated how, in the future climate case, the intra-specific crop biodiversity, in combination with cropping patterns better adapted to soil characteristics, may allow the current production system to be maintained.