Climate Change Effects on the Suitability of an Agricultural Area to Maize Cultivation: Application of a New Hybrid Land Evaluation System

Climate change is likely to have a major impact on agricultural production in Mediterranean regions, due to higher temperatures and lower water availability for irrigation. A Hybrid Land Evaluation System (HLES) is proposed allowing a comparison between plant demands on the one hand and estimated future temperatures and soil water regimes on the other. A storyline is followed for each plant species hybrid and each soil mapping unit in the area to be studied, starting with step 1: evaluation of thermal conditions, followed by step 2: a traditional empirical land evaluation procedure identifying limiting features that are not covered by crop simulation models (such as flooding, surface stones, salt). Step 3 applies the quantitative Soil-Water-Atmosphere-Plant (SWAP) model and calculates soil water regimes and associated productions, at 100%, 80%, and 60% hypothetical irrigation water availability. HLES was applied in the Destra Sele area in Italy, comparing two climates: "reference" (1961-1990) and "future" (2021-2050), studying 11 maize hybrids and showing that in future, 6 hybrids suffered severely at 80% water availability and 7 could not meet requirements at 60%. HLES allows a proactive approach to future water allocation issues and provides data for genetic modification studies in terms of defining hydrological conditions for sites of native plants and for areas where new hybrids are to be introduced. HLES presents options, to be explored in close interaction with users, rather than one-way judgments.