The Impacts of Climate Change on Irrigated Agriculture in Southern Portugal

Abstract

Climate change projections point to increasing air temperature and reduced precipitation in southern Portugal, which would affect farming systems. This study aims to assess the impacts of climate change on irrigated agriculture in southern Portugal. These impacts were assessed by combining climate model data with a soil water balance model and a numerical model for the design of irrigation systems. Meteorological data from two weather stations were used along with three climate models (HadRM3P, HIRHAMh and HIRHAMhh; 2071-2100). The crop rotations studied included sugar beet-maize-tomatowheat and sunflower-wheat-barley. Two adaptation measures were considered: (i) maintaining the current crop varieties; (ii) using new crop varieties. The results from the considered climate change scenarios indicated that the impacts of climate change on irrigation requirements depend on the adopted adaptation measures. On average, the seasonal irrigation requirements increased by 13-70% when new crop varieties were used and by À13 to 7% when the current crop varieties were maintained. The impacts of climate change on irrigation system design were considerable, with the design flow rate increasing by 5-24%. Copyright © 2016 John Wiley & Sons, Ltd.Key words: Climate change; Crop irrigation requirements; Irrigation; Irrigation systems; Models; Soil water balance RÉSUMÉ Les prévisions de changement climatique indiquent un accroissement de la température de l'air et une diminution de la précip-itation dans le Sud du Portugal, ce qui affecterait les systèmes de production agricole. Cette étude a pour but d'évaluer les impacts du changement climatique sur l'agriculture irriguée dans le Sud du Portugal. Ces impacts ont été évalués en combinant les données de modèles climatiques avec un modèle de bilan hydrique du sol et un modèle numérique pour la conception des systèmes d'irrigation. Les données de deux stations météorologiques ont été utilisées avec trois modèles climatiques (HadRM3P, HIRHAMh et HIRHAMhh; 2071-2100). Les assolements étudiés comprenaient: betterave sucrière-maïs-tomate-blé et tournesol-blé-orge. Deux mesures d'adaptation ont été considérées: (i) en conservant les variétés cultivées actuellement et (ii) en utilisant de nouvelles variétés. Les résultats obtenus à partir des scénarios de changement climatique considérés indiquent que les impacts du changement climatique sur les besoins en irrigation dépendent des mesures d'adaptation choisies. En moyenne, les besoins saisonniers en irrigation augmentent de 13 à 70% quand les nouvelles variétés sont utilisées, et de À13 à 7% quand les variétés actuelles sont maintenues. Les impacts du changement climatique sur la conception des systèmes d'irrigation sont considérables avec une augmentation du débit de projet de 5 à 24%.

Effects of climate change and adaptation options on winter wheat yield under rainfed Mediterranean conditions in southern Portugal

“…A modeling study in major wheat growing regions of Australia suggested that variations in mean growing season temperature by ± 2°C could impose a substantial reduction on wheat grain production by up to 50% (Asseng et al 2011). Observed climate conditions in southern Portugal have shown a clear trend toward a more arid climate, with increased mean temperature and decreased annual precipitation, particularly spring precipitation (Páscoa et al 2017;Rolim et al 2017;Valverde et al 2015). The observed warming and drying trends are likely to be strengthened in future climates (Páscoa et al 2017;Rolim et al 2017), with a concomitant increase in the frequency and intensity of extreme weather events, e.g., droughts (Santos et al 2016).…”

“…Previous studies on potential climate change influences on wheat production in Portugal were focused on either assessing crop water deficits (Rolim et al 2017) or using climate change projections without accounting for the potential changes in climate variabilities and associated extreme events (Valverde et al 2015). Besides, neither of these studies attempt to explore adaptation strategies.…”

Assessing Quality of Reclaimed Urban Wastewater from Algarrobo Municipality to Be Used for Irrigation

“…In the province of Malaga RW is not yet used for agricultural irrigation. Using RW for irrigation purposes, in addition to savings of freshwater supplies, can partially supply some nutrients, particularly nitrogen, phosphorous, and potassium, which are the primary nutrients needed to stimulate yield and quality of agricultural crops [11]. Considering that RW may contain a high content of essential nutrients for plants, the use of this water to elaborate the irrigation solution could significantly reduce the application of standard commercial fertilizers and its associated costs.…”

Impacts of Climate Change on Urban Extreme Rainfall and Drainage Infrastructure Performance: A Case Study in Wuhan City, China

“…However, the stationary assumption is being increasingly challenged by climate change (Milly et al, 2008;Li et al, 2017;Rolim et al, 2017;Yan et al, 2017a;Xu et al, 2018;Zhang et al, 2018). design rainfall) derived from the probability distribution of extreme rainfall, which is based on historical rainfall records and assumed to be stationary.…”

“…design rainfall) derived from the probability distribution of extreme rainfall, which is based on historical rainfall records and assumed to be stationary. However, the stationary assumption is being increasingly challenged by climate change (Milly et al, 2008;Li et al, 2017;Rolim et al, 2017;Yan et al, 2017a;Xu et al, 2018;Zhang et al, 2018). It is anticipated that the frequency and magnitude of extreme rainfall will increase due to global climate change (Intergovernmental Panel on Climate Change (IPCC), 2013).…”