Phytotoxicity and fertilising potential of olive mill wastewaters for maize cultivation

The use of organic wastes as agricultural amendment is an effective strategy to regenerate degraded soils and represents an economical alternative that provides a local source of fertiliser. Olive mill wastewaters are widely known for their fertilising value. However, they can still not be recommended as a safe practice because of their potential ecological risks. Here, the effect of olive mill wastewaters on maize is investigated. Olive mill wastewater samples were collected in semi-modern and traditional mills of the Marrakech area, Morocco. Samples were analysed for pH, electrical conductivity and total phenolic content. Major phenolic compounds were identified and quantified. Phytotoxicity was assayed in the laboratory using maize seedlings, and under field conditions. Field fertilisation was conducted through land application accompanied or not by foliar spray according to a fractionated application mode. Our results show a high variability in physicochemical characteristics of wastewaters, notably for phenolic profiles. Variable toxicity levels were also attributed to each sample according to its salinity and phenolic load. Under field conditions, a 9% reduction of seedling emergence was observed in olive mill wastewater-pre-treated soil as compared with the control. However, olive mill wastewater-fertilised plots showed a net improvement in plant height of 10–11% compared with the control. A yield improvement reached 28% over that of the control when the plants were amended both by land application and foliar spray. These results show that the large variability in olive mill wastewaters composition constitutes a major limiting factor for their re-use in agricultural systems. Olive mill wastewaters can be used as a safe agronomic amendment provided the application is moderate and progressive and critical development stages are avoided, notably the preliminary development stages. Foliar fertilisation using olive mill wastewaters is also revealed to be a promising way to manage these effluents

Problématique de la phœniciculture au Maroc

Importance écologique et socio-économique du palmier dattier Le palmier dattier (Phœnix dactylifera L.) est « l’arbre » fruitier par excellence du désert où il constitue le pivot de l’agriculture oasienne caractérisée par une stratification et une association de plusieurs cultures sous jacentes. Aussi, le dattier présente l’immense bénéfice de lutter contre la désertification par l’interception du rayonnement solaire intense et la mise en place d’un « barrage vert et productif », l’oasis. La ..

Variation of morphological traits in natural populations of maritime pine (Pinus pinaster Ait.) in Morocco

Pinus pinaster Ait. is the main species used for reforestation in Morocco, both in mountain and low lands areas. However, little information is available about its intraspecific variation and adaptability in this range. This work studied the morphological variation of nine native populations, covering the distribution area of maritime pine in Morocco (Rif, Middle Atlas and High Atlas). Thirteen morphological and anatomical traits from cones (length and width), seeds (length, width, thickness and weight), seed wings (length and width) and needles (length, width, thickness and the number of stomata rows on the dorsal and convex faces of the needle) were measured in 232 trees. A Principal Component Analysis was used to explain the variation observed in four principal components related to cone (PCA3), seed (PCA1) and needle (PCA2 and PCA4) traits. Variability in morphological traits was high in Moroccan populations of maritime pine and significant differences among populations were found. Moreover, cone and needle traits showed clinal variation responding to latitude/altitude gradients. A hierarchical classification of all populations led to the formation of three major groups: (i) Mediterranean coastal populations, (ii) southeastern Rif, composed only by one population and (iii) the rest of populations, widely distributed through Moroccan maritime pine range.Variation des caractères morphologiques des populations naturelles du pin maritime (Pinus pinaster Ait.) au Maroc. Pinus pinaster Ait. est une espèce forestière habituellement choisie pour le reboisement au Maroc, aussi bien dans la montagne que dans la plaine. Cependant, peu de données sont disponibles sur sa variabilité et adaptabilité intra spécifiques dans ces milieux. Ce travail a permis d’étudier la variabilité morphologique de neuf populations indigènes, couvrant l’aire du pin maritime au Maroc (Rif, Moyen Atlas et Haut Atlas). Treize caractères morphologiques et traits anatomiques des cônes (longueur et largeur), des graines (longueur, largeur, épaisseur et poids), des ailes de graine (longueur et largeur) et des aiguilles (longueur, largeur, épaisseur et le nombre des lignes stomatiques sur les faces dorsales et convexes de l'aiguille) ont été mesurés sur 232 arbres. Une analyse en composantes principales a été employée pour expliquer la variance observée. Les quatre principaux axes correspondent à des caractères liés aux cônes (PCA3), aux graines (PCA1) et aux aiguilles (PCA2 et PCA4). La variabilité des caractères morphologiques est importante dans les populations marocaines de pin maritime et des différences inter populations significatives ont été mises en évidence. D’autre part, les caractéristiques des cônes et des aiguilles ont montré une variation clinale répondant aux gradients de latitude/altitude. La classification hiérarchique basée sur les caractères morphologiques de toutes les populations a conduit à l’individualisation de trois groupes principaux : (i) les populations de la côte méditerranéenne, (ii) une population du sud-est du Rif et (iii) le reste des populations, qui sont dispersées dans toute l’aire de répartition du pin maritime au Maroc