A field survey suggests changes in oasis characteristics in the Kebili region of southern Tunisia

Abstract

Since their establishment, “traditional” oases have been known to be three-layered, while modern oaseshave been organized from their outset with one layer only of ‘Deglet Nour’ date palm cultivars. However, these definitions may no longer apply for Kebilian oases. A survey was therefore carried out on a random sample of 52 plots in Kebilian oases (“traditional” n=26 and “modern” n=26) to investigate the current situation. The data collected were analysed by the Pivot Tables method and a Chi-2 test of independence, and by a Multiple Component Analysis completed by an Ascending Hierarchical Classification analysis to characterise and classify each oasis type. Our results showed that “modern” oases have greater crop diversity than expected and can be organized in two or three-layer oases. In contrast, high crop diversity and the three vertical layers were found to be less frequent than expected in “traditional” oases. Our investigation found water availability in the oases, and irrigation frequency, to be the key factors of Kebilian oasis layout and typology changes. Agro-biodiversity losses could jeopardize the sustainability of the oasis system in “traditional” oases.

The oasis extensions: Typology and heterogeneity of profiles in Toudgha

“…This type of analysis makes it possible to go beyond a "fixed" dichotomy of ancient oases, which are awarded heritage status and the extensions, which overexploit groundwa-ter resources (Carpentier et al, 2021). Other studies clearly showed that farms in the ancient oasis that lack water tend to cultivate monocrops, while in the extensions; farms tend toward crop diversification and to a 2-3 tier system (Benmoussa et al, 2022). Further studies would improve our knowledge of the links between the ancient oases and their extensions.…”

“…In Tunisia, except where the state created the extensions, these lands are considered illegal but still play an important role in the oasis economy thanks to private investments and their extent has increased rapidly in the last two decades. For example, the agricultural extensions in Kebili (Tunisia), are four times bigger than the original oasis (Benmoussa et al, 2022;Mekki et al, 2021). In Morocco, oasis extensions are an integral part of the agricultural and collective land liberalisation policy (Mahdi, 2020;Kadiri and Er-rayhany, 2019).…”

Response of Date palm trees Phoenix dactylifera L. Khastawi cultivar to chemical, organic and biological fertilization

“…Also, biological fertilizers encourage biological processes inside the plant, which increases the efficiency of carbon metabolism and the accumulation of materials manufactured in this process and its transmission from the leaves and the rest of the branches to the fruits, and this leads to an increase in the number of fruits and the average weight of the fruit. In the end, an increase in the production of fruits 26 and the improvement of the biological activity in soil 27 , in turn, significantly increase the set percentage and, thus, increase the total yield.…”

Making sense of on-going dynamics and innovations in oases and newly irrigated areas of North African arid regions: towards more sustainable development pathways

“…The articles in this special issue are organised in four topics: evolving agroecosystems, water use and governance, innovation and entrepreneurial systems, and emerging value chains. Benmoussa et al (2022) characterise the dynamics of irrigated systems based on palm groves in Kebili Region, Tunisia, where traditional oases have been three-layered, whereas, at the outset, the newly irrigated areas only had one layer comprised of the Deglet Noor date cultivar. The study shows that this typology no longer applies.…”

“…In Drâa Tafilalet Region, the expansion of watermelon cultivation led to a decrease in crop diversity and in livestock breeding (Sraïri and Naqash, 2022). Conversely, in Kebili Region, water availability is a major factor enabling crop diversity, which may be higher in extensions than in traditional oases (Benmoussa et al, 2022). In extension areas in Drâa Tafilalet Region and in those located in the periphery of traditional oases in Ghardaïa Region, some farmers replicate the logics of three-layer cropping and are aware of the link between cropping and livestock breeding.…”