Integrating Farmers’ Perceptions and Crop Modelling to Evaluate Agronomic Adaptation Measures for Irrigated Maize Under Climate Change

Farmers’ knowledge is critical for identifying agronomic adaptation measures (AAMs) to cope with climate change. A farmer-informed approach was used to select AAMs. Farmers’ perceptions were collected through a semi-structured survey involving 50 farmers, and the most frequent AAMs were evaluated using the AquaCrop-OSPy model. Simulations covered a baseline (1971–2000) and future period (2041–2070) under two SSP climate scenarios. Four AAM groups were assessed against the standard cropping system: (i) shorter and longer crop cycles; (ii) earlier sowing dates; (iii) variations in sowing density; and (iv) improved irrigation efficiency. The first three AAM groups were directly simulated, while the fourth was incorporated during post-processing. Evaluation considered irrigation requirements (IR), actual yield (Ya), irrigation water productivity (IWP), and gross production value (GPV). Results indicate that higher temperatures accelerate development and shorten the crop cycle. However, projected decreases in spring precipitation increase IR by 2–4% and reduce yields by 4–6% in future scenarios without adaptation, negatively affecting GPV. Early sowing with short-season varieties at moderate to high densities reduces IR by 29–34% but entails yield penalties of 53–55%; long-season varieties with high density increase Ya by 3–13% when water is not limiting; and medium-season varieties with anticipated sowing, high density, and 90% irrigation efficiency increase IWP by 22–25%. Tailored AAMs balance water, productivity, and economic value, enhancing climate resilience in the Mediterranean.