atmosphere Article GIS-Based Land Suitability and Crop Vulnerability Assessment under Climate Change in Chtouka Ait Baha, Morocco Marieme Seif-Ennasr 1,*, Lhoussaine Bouchaou 1,2 , Zine El Abidine El Morjani 3, Abdelaziz Hirich 4, El Hassane Beraaouz 1 and Redouane Choukr-Allah 5 1 Applied Geology and Geoenvironment Laboratory, Faculty of Sciences, Ibn Zohr University, Agadir 80000, Morocco; [email protected] (L.B.); [email protected] (E.H.B.) 2 International Water Research Institute, (IWRI), Mohammed VI Polytechnic University (UM6P), Ben Guerir 43150, Morocco 3 Polydisciplinary Faculty of Taroudant, Ibn Zohr University, Taroudant 83000, Morocco; [email protected] 4 African Sustainable Agriculture Research Institute (ASARI), Mohammed VI Polytechnic University (UM6P), Laayoune 70000, Morocco; [email protected] 5 Agronomic and Veterinary Medicine Hassan II Institute, Rabat 10000, Morocco; [email protected] * Correspondence: [email protected]; Tel.: +212-665616271 Received: 22 September 2020; Accepted: 4 October 2020; Published: 29 October 2020 Abstract: Agriculture plays a crucial role in the economic development in Morocco, contributing to 14% of the national gross domestic product. However, this sector is facing various challenges, including climate change. This study aims to assess relevant indicators that may affect land suitability, water demand, and crop growing season duration under climate change. Further, it may be used as a decision support tool in the Chtouka area known for its irrigated agriculture. The approach proposed, the spatial distribution of land based on suitability, is founded on the multiple-criteria decision-making method of four parameters; soil texture, temperature, land use, and slope. The duration of the length of crop season was simulated using the concept of growing degree days. The projection of land suitability for 2031–2050 indicated an important decrease of 12.11% of “highly suitable” agricultural land under the RCP4.5 emission scenario and a significant increase of 4.68% of “highly unsuitable” land, according to the RCP8.5 emission scenario compared to the baseline (1985–2005). The projected growing degree days in 2031–2050 showed a strong shortening in the growing period length compared to the baseline 1985–2006, mainly under the RCP8.5 emission scenario, with a reduction from 8% to 21% depending on crops. Moreover, crop water productivity indicated that berries were over 50% less water productive than other vegetable crops for almost the same amount of applied irrigation water. These findings highlight the vulnerability of agriculture to climate change, which requires important political and management efforts to sustain agricultural activity. Keywords: GIS; land suitability; MCDM model; growing period length; growing degree days; crop water productivity; climate change 1. Introduction Agriculture plays a significant socio-economic role in the development of the Kingdom of Morocco. Nowadays, this sector contributes up to 14% of the gross domestic product (GDP) [1]. Many scientists have raised concerns about food supply and demand in response to the pressure of a growing population and increased water consumption in the agricultural sector in several developing countries [2,3]. Therefore, in an effort to achieve self-sufficiency in agricultural production, designing Atmosphere 2020, 11, 1167; doi:10.3390/atmos11111167 www.mdpi.com/journal/atmosphere Atmosphere 2020, 11, 1167 2 of 23 innovative approaches to predict the climate and land suitability for different types of agriculture is necessary. The net impact of long-term progressive climate change on crop yields is a major concern for both farmers and policymakers at the local, national, and regional levels [4]. It is axiomatic that inappropriate land use results in land degradation and decline in agricultural productivity. Reliable, accurate land suitability assessment is, therefore, required for the policy-making process to support sustainable agriculture development. Land suitability analysis (LSA) is a key tool for rational land use planning and optimizing resource use for the present and in the future in several countries, as well as in Morocco. It can be assessed through the identification of the main limiting factors of agricultural production, whose optimum utilization enables decision-makers and farmers to achieve efficient land management. Land suitability is a multi-dimensional problem that involves the combination of numerous factors (topographic, soil, climatic, and management factors). Therefore, its evaluation requires a multi-criteria decision making (MCDM) approach to make proper management decisions, especially where the productivity of the land is limited. Several GIS-based land suitability analyses have been developed, such as fuzzy evaluation and the Boolean overlay [5,6]; however, climate suitability has not been sufficiently addressed. Temperature is a main climatic driver that affects the crop growth rate. The warmer temperatures expected with climate change and the potential for more extreme temperature events, such as drought, will impact water availability and plant productivity [7,8]. Climate change could affect crop production through many different mechanisms [9,10]. Interestingly, on the one hand, it may have impact on the length of crop season (LCS). In fact, Alexandrov and Hoogenboom [11] demonstrated that higher temperatures and a precipitation deficit shortened the winter wheat and maize growing seasons and, consequently, decreased their yield. Furthermore, Challinor et al. [12] found that the optimal temperature should not exceed 36.8 ◦C, as the mean yields fall significantly due to a shortened crop duration. Moreover, through Providing REgional Climates for Impacts Studies, pronounced pray-sea (PRECIS) model simulations, Jalota et al. [13] predicted a future reduction in rice and wheat yields associated with a shortening of the growth period due to increased temperature. On the other hand, less frequent and more intense precipitation, in addition to higher evapotranspiration, may increase water stress and diminish crop water productivity, as demonstrated by Amisigo et al. [14]. In the early 1990s, agricultural activity was extended in areas where the factors of production were abundant (good soil, labor availability, access to inputs, underground and superficial water availability); however, no measure of optimization of these resources was taken into consideration. Today, given the scarcity of resources, it is necessary to adopt scientific methods to evaluate the exploitability of existing lands and to guide future extensions. Furthermore, many studies have focused on the impacts of climate change on agricultural sustainability with respect to crop productivity, water availability, and demand. However, there is obviously limited literature on the impacts of potential changes in land suitability, which has a critical role in formulating future land policies. Thus, the main objectives of this work are to (1) identify the influencing parameters (climatic and physical) that have an impact on land cropping, (2) generate crop suitability maps based on the weighted combination method of the studied parameters under different climate change scenarios towards 2050, and (3) project the crop behavior with respect to water demand and growing period length under climate change. 2. Study Area Already known to be the best agricultural area in Morocco, and with a surface of 34,354 km2, Chtouka Ait Baha is considered the agricultural center of the region of Souss–Massa. This area is characterized by a suitably sloping topography, sandy soils, and an existing irrigation network that includes canals from the Youssef Ibn Tachfin dam, with an irrigated area in the Chtouka–Massa plain Atmosphere 2020, 11, 1167 3 of 23 of 1500 km2. The modern, irrigated agriculture focuses on early crops of high quality that are destined Atmosphere 2020, 11, x FOR PEER REVIEW 3 of 25 for export markets, which have steadily gained ground internationally in the last ten years. TheThe regionregion isis surroundedsurrounded toto thethe northnorth byby twotwo mountainmountain ranges:ranges: TheThe WesternWestern HighHigh AtlasAtlas andand thethe EasternEastern HighHigh Atlas,Atlas, andand inin thethe south,south, byby thethe Anti-Atlas.Anti-Atlas. ToTo thethe westwest isis thetheAtlantic AtlanticOcean Ocean (Figure (Figure1 ).1). FigureFigure 1.1. LocationLocation andand elevationelevation ofof thethe studystudy areaarea (Chtouka(Chtouka AitAit Baha).Baha). 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