Conservation agriculture in the dry Mediterranean climate

The objective of this article is to review: (a) the concepts and principles that underpin Conservation Agriculture (CA) ecologically and operationally; (b) the potential benefits that can be harnessed through CA systems in the dry Mediterranean climates; (c) current status of adoption and spread of CA in the dry Mediterranean climate countries; and (d) opportunities for CA in the Central and West Asia and North Africa (CWANA) region. CA, comprising minimum mechanical soil disturbance and no-tillage seeding, organic mulch cover, and crop diversification is now practised on some 125 million ha, corresponding to about 9% of the global arable cropped land. Globally, the area under CA is spread across all continents and all agro-ecologies, including the dryland climates in the Mediterranean basin region as well as in the Mediterranean climates elsewhere in the world. Worldwide empirical and scientific evidence is available to show that significant productivity, economic, social and environmental benefits exist that can be harnessed through the adoption of CA principles for sustainable production intensification in the dry Mediterranean climates, including those in the CWANA region. The benefits include: fundamental change for the better in the sustainability of production systems and ecosystem services; higher stable yields and incomes; climate change adaptation and reduced vulnerability to the highly erratic rainfall distribution; and reduced greenhouse gas emissions. CA has taken off globally and is now spreading in several Mediterranean climates outside the Mediterranean basin particularly in South America, South Africa and Australia. In the dry Mediterranean climates in the CWANA region, CA is perceived to be a powerful tool of land management but CA has not yet taken off. Research on CA in the CWANA region has shown that there are opportunities for CA adoption in rainfed and irrigated farming systems involving arable and perennial crops as well as livestock

Effect of tillage practices on the soil carbon dioxide flux during fall and spring seasons in a Mediterranean Vertisol

In this study, we assessed the effect of conventional tillage (CT), reduced (RT) and no tillage (NT) practices on the soil CO2 flux of a Mediterranean Vertisol in semi-arid Morocco. The measurements focused on the short term (0 to 96 h) soil CO2 fluxes measured directly after tillage during the fall and spring period. Soil temperature, moisture and soil strength were measured congruently to study their effect on the soil CO2 flux magnitude. Immediately after fall tillage, the CT showed the highest CO2 flux (4.9 g m-2 h-1); RT exhibited an intermediate value (2.1 g m-2 h-1) whereas the lowest flux (0.7 g m-2 h-1) was reported under NT. After spring tillage, similar but smaller impacts of the tillage practices on soil CO2 flux were reported with fluxes ranging from 1.8 g CO2 m-2 h-1 (CT) to less than 0.1 g CO2 m-2 h-1 (NT). Soil strength was significantly correlated with soil CO2 emission; whereas surface soil temperature and moisture were low correlated to the soil CO2 flux. The intensity of rainfall events before fall and spring tillage practices could explain the seasonal CO2 flux trends. The findings promote conservation tillage and more specifically no tillage practices to reduce CO2 losses within these Mediterranean agroecosystems. (Résumé d'auteur

First principles calculations of electronic and optical properties for mixed perovskites: Ba (1-x) Ca (x) TiO 3 and Ba (1-x) Sr (x) TiO 3 (x=0.4, 0.6)

International audienceThe effect of Ca and Sr-doping on the structural electronic and optical properties of the cubic Ba1-xCaxTiO3 and Ba1-xSrxTiO3 (x=0.4, 0.6) mixed crystals was investigated using first-principles calculations based on density functional theory (DFT). The calculated band structures based on the optimized geometry of the cell for the solid solutions show an indirect band gap character at M-points, with low energy dispersion along height symmetry directions in the Brillouin zone. The band gaps increase with Ca and Sr concentrations. The total and partial densities of states were analyzed to examine the contribution of different orbitals to the maximum of valence band and the minimum of the conduction band. The optical properties such as reflectivity, energy loss, refractive index and extinction coefficient were studied

Optimization of NPK levels of Clementine Sidi Aissa (Citrus reticulata Blanco) trees grafted on different citrus rootstocks

Received: August 15th, 2023 ; Accepted: October 18th, 2023 ; Published: November 5th, 2023 ; Correspondence: [email protected] present study aims to investigate the impact of various nitrogen concentrations on young Clementine Sidi Aissa citrus trees (Citrus reticulata Blanco), grafted on five citrus rootstocks namely Moroccan Carrizo citrange, French Carrizo citrange, Troyer citrange, Citrus macrophylla, and sour orange (Citrus aurantium L.). The experiment took place in greenhouses at the Experimental station of El Menzeh INRA-Morocco, with the young trees grown in containers. We applied five different nitrogen treatments (expressed as mg L-1 of N-P2O5-K2O): (0–0–0), (0–25–50), (25–25–50), (50–25–50), and (100–25–50). The split-plot experimental design was used with three replications. The findings demonstrate that the nitrogen enrichment resulted in enhanced plant growth, marked by increased plant height, rootstock and scion stem diameters, diameter and shoot length, relative water content (RWC), as well as leaf chlorophyll and proline content. Optimal growth of the Clementine Sidi Aissa trees was observed under the 100–25–50 (mg L-1 of N-P2O5-K2O) treatment. The study also found that leaf nitrogen concentration increased in line with the quantity of nitrogen added, whereas the percentages of phosphorous and potassium in the leaves decreased. The most significant growth increase across the majority of the studied parameters was noted in Clementine Sidi Aissa trees grafted on Moroccan Carrizo citrange and Troyer citrange rootstocks

Tillage system affects soil organic carbon storage and quality in Central Morocco

Stabilizing or improving soil organic carbon content is essential for sustainable crop production under changing climate conditions. Therefore, soil organic carbon research is gaining momentum in the Mediterranean basin. Our objective is to quantify effects of no tillage (NT) and conventional tillage (CT) on soil organic carbon stock (SOCs) in three soil types (Vertisol, Cambisol, and Luvisol) within Central Morocco. Chemical analyses were used to determine how tillage affected various humic substances. Our results showed that, after 5 years, surface horizon (0–30 cm) SOC stocks varied between tillage systems and with soil type. The SOCs was significantly higher in NT compared to CT (10% more in Vertisol and 8% more in Cambisol), but no significant difference was observed in the Luvisol. Average SOCs within the 0–30 cm depth was 29.35 and 27.36 Mg ha−1 under NT and CT, respectively. The highest SOCs (31.89 Mg ha−1) was found in Vertisols under NT. A comparison of humic substances showed that humic acids and humin were significantly higher under NT compared to CT, but fulvic acid concentrations were significantly lower. These studies confirm that NT does have beneficial effects on SOCs and quality in these soils

Page number not for citation purposes 1 Des Furoncles résistants aux antibiotiques: penser à la myiase !!

Les myiases sont des infections parasitaires par des larves de mouches. La localisation cutanée doit être évoquée de retour d'un pays tropical devant une évolution inhabituelle de lésions cutanées. Nous rapportons une observation d'un militaire tunisien, ayant séjourné en République Démocratique du Congo. Il était atteint de myiase cutanée simulatrice d'une furonculose résistante aux antibiotiques. L'intérêt de cette observation est de souligner l'importance d'évoquer la myiase dont le traitement est simple et rapide chez un patient de retour de zone d'endémie.Key words: Furoncles, myiase, mouche

Optimización de la extracción de aceite de semilla de dátil mediante la ayuda de tecnologías hidrotermales y de ultrasonido

The date seed is a by-product from the date industry. Its use as a source of added-value compounds is of great interest. Oil accounts for 5-13% of the seed’s weight. Soxhlet extraction with organic solvents is the traditional method for obtaining oil from seeds. In this work, hydrothermal pre-treatments and sonication are proposed to make the extraction a more environmentally friendly process. Factors such as sonication time and temperature and hexane-to-seed ratio (H/S) have been considered. Response surface methodology was applied for optimization. Hydrothermal treatments increased oil recovery. H/S was the most influential factor, and was close to 7 mL/g seeds for both samples. 71% recovery was achieved for native seeds after 15 min sonication at 45 ºC, and 80% for 180 ºC-treated seeds after 45 min at 35 ºC when compared to Soxhlet extraction. These conditions comply with our initial aim. Pre-treatments seem to have a negative effect on oil stability, although this observation needs to be confirmed.La semilla de dátil es un subproducto de la industria datilera. Su uso como fuente de compuestos de valor añadido sería muy interesante. El aceite representa el 5-13% del peso de la semilla. La extracción mediante Soxhlet con disolventes orgánicos es el método tradicional para obtener aceite de semillas. En este trabajo se proponen pretratamientos hidrotérmicos y sonicación para diseñar un proceso de extracción más respetuoso con el medio ambiente. Se han considerado factores como el tiempo y la temperatura de sonicación y la proporción hexano/semilla (H/S). La optimización del proceso se llevó a cabo por el método de superficie de respuesta. Los tratamientos hidrotérmicos aumentaron el porcentaje de recuperación. El factor más influyente fue H/S, y su valor óptimo estuvo cerca de 7 mL/g para ambas muestras. La recuperación óptima fue del 71% para las semillas sin tratamiento tras 15 min de sonicación a 45 ºC, y del 80% para las semillas tratadas a 180 ºC después de 45 min a 35 ºC. Estos resultados cumplen con nuestro objetivo inicial. Sin embargo, los pretratamientos parecen tener un efecto negativo sobre la estabilidad del aceite, lo que se confirmará en estudios posteriores

La fertilisation améliore la production des prairies humides naturelles dans la montagne du haut Atlas oriental du Maroc : cas de la région d'Imilchil

The oriental High Atlas mountains in southeast of Morocco are characterized by small natural wet grasslands called “Almous”, they are suitably well managed by the local population. They are destined to feed cattle and mullets. This trial was implemented in order to assess the effects of nitrogen fertilization on the phytomass production on the Tissila meadow (6.5 Ha) in Imilchil region. The experimental design consisted in dividing the meadow into 3 parcels. One parcel is leaved as control and the other two parcels have received two doses of nitrogen during three periods in the year (D1 =67 kg N/ha (split in three applications October, April and May) plus 46 Kg P2O5/ha (split in two applications April and May); D2 (with applications as D1=134kg N/ha more 46 Kg P2O5/ha; D3 = control). The phytomass production has doubled in Tissila region due to the effect of fertilization basically for dose (D2). The assessment of flora revealed a great specific richness (79 species) and some endemism.Les montagnes orientales du Haut Atlas au sud-est du Maroc sont caractérisées par de petites prairies humides naturelles applées "Almous" elles sont convenablement bien gérées par la population locale. Ellesont destinées à nourrir les bovins et mulets. Un essai a été réalisé pour évaluer les effets de la fertilisation azotée sur la production de la prairie de Tissila, (6,5 Ha) dans la région d'Imilchil. Le plan expériemental consistait à diviser la praiire en 3 parcelles. Une parcelle est laissée comme témoin et les deux autres parcelles ont reçu deux doses d'azote pendant trois périodes de l'année (D1 = 67 kg N / ha (réparti en trois applications en octobre, avril et mai) plus 46 kg de P2O5 / ha  en deux applications (en avril et mai); D2 (avec les mêmes applications en D1) = 134 kg N / ha plus 46 kg P2O5 / ha; D3 = contrôle). La production de phytomasse a doublé dans la région de Tissila en raison de l'effet de la fertilisation surtout pour la D1. L'évaluation de la flore a révélé une grande richesse spécifique (79 espèces) et une certaine endémicité qui mérité d'être sauvegardée

Salsola vermiculata espèce prometteuse pour la réhabilitation des pâturages présahariens du Maroc

Salsola vermiculata L. Syn. Caroxylon villosum (Delile) Akhani & Roalson (Chenopodiaceae) is a perennial small woody species widely distributed in arid zones of Middle East and North Africa (MENA) region. It is one of the promising pastoral species for the rehabilitation of arid rangelands in Mororcco. The objectives of this study were to determine the effects of temperature and duration of seed storage on the germination of Salsola vermiculata, to determine the optimal transplant age of Salsola vermiculata seedlings and to compare the production of two varieties of Salsola vermiculata (villosa and brevifolia). The germination tests were carried out in a germination incubator at the laboratory of the Errachidia experimental station. 12 temperature regimes and three durations of seed storage were tested. For transplantation, comparisons were made between villosa variety seedlings of 1.5 months, 4 months and 8 months. In addition, the production the 8-month-old seedlings of the two varieties of Salsola vermiculata (var. villosa and var. brevifolia) were compared. The percentage of germination and the germination rate were very high for several temperature regimes, except for the high temperatures. In addition, it decreased very significantly with the storage duration of the seeds. Regarding the age of seedling transplants, the eight-month-old seedlings were the best in terms of production and growth rate. In addition, the villosa variety produced very significantly more phytomass than the local variety brevifolia.Salsola vermiculata L. (Chenopodiaceae) est une ligneuse basse largement répandue dans les zones arides du Moyen-Orient et de l’Afrique du Nord (MENA). C'est l'une des espèces pastorales prometteuses pour la réhabilitation des pâturages arides du Maroc. Les objectifs de cette étude sont de déterminer les effets de la température et de la durée de stockage des graines sur la germination de Salsola vermiculata, de déterminer l’âge optimal de transplantation des plantules de Salsola vermiculata et de comparer la production de deux variétés de cette espèce (variétés villosa et brevifolia). Les essais de germination sont menés dans une enceinte de germination au laboratoire de la station expérimentale d'Errachidia. Douze régimes de température et trois durées du stockage de graines sont testés. Pour la transplantation, des comparaisons sont effectuées entre des plants de 1.5 mois, 4 mois et 8 mois de la variété villosa. En outre, la comparaison de la production des plantules de 8 mois des deux variétés de Salsola vermiculata (villosa et brevifolia) sont effectuées. Les résultats montrent que le pourcentage de germination et la vitesse de germination sont très élevés pour plusieurs régimes de température, sauf pour les hautes températures. En outre, ils diminuent très significativement avec la durée de stockage des graines. Concernant, l’âge de transplantation, les plantules de 8 mois se comportent mieux des points de vue reprise, production et croissance. En outre, la variété villosa a produit très significativement plus de phytomasse que la variété locale brevifolia

Salinité et pollution par les nitrates des eaux souterraines de la plaine des Triffa

Les eaux souterraines de la plaine des Triffa (Basse Moulouya) deviennent de plus en plus polluées. Les résultats analytiques montrent que la plupart des puits sont chargés en sels et en nitrates, donc impropres à la consommation humaine et peuvent avoir un effet négatif sur les cultures maraîchères de la région. Dans la zone étudiée, des teneurs de 2,32 à 174,70 mg/l de NO3-, de 134 à 3614 mg/l de Cl- et de 103 à 1518 mg/l de Na+ ne sont pas exceptionnelles. Elles dépassent largement les normes fixées par l’OMS et la CEE (50 mg/l pour les NO3 -, de 250 mg/l pour Cl- et de 175 mg/l pour Na+). L’intensification de l’agriculture dans la plaine, notamment dans les périmètres irrigués, l’épandage excessif des engrais, les applications répétées, et à quantités fortes, de fumiers, l’irrigation, les précipitations et la remontée de la nappe dans certaines régions ont engendré une pollution croissante des ressources en eau