DEPARTEMENT DES SCIENCES AGRONOMIQUES

An inventory was carried out at five stations in the oasis of Ziban, an oasis that is characterized by its high-quality dates, in order to study the relationships between the oasis ecosystem and its insect fauna. Specimens were sampled using pitfall traps containing ethylene glycol as a preservative. In total, 115 arthropod species were collected during 5 months of survey. These species belonged to 61 families, 17 orders, and 4 classes (12 orders from Insecta, 3 from Arachnida, 1 from Chilopoda, and 1 from Malocostraca). The most represented insect orders were Coleoptera (44.42%), Hymenoptera (20.86%), and Lepidoptera (7.87%). Represented in the collections were phytophagous, omnivorous, and predator/parasite species. Given the large number of species collected, and the largely unknown relationships existing between the various ecological groups, this study is a first step in the description of the oasis entomofauna. RESUMEN. Dans les oasis des Ziban, cinq stations qui se caractérisent par la haute qualité des dattes produites, ont fait l'objet d'un inventaire, afin d'e ´tudier les relations entre l'e ´cosystè me oasien et l'entomofaune qui y habite. Les exemplaires ont e ´té e ´chantillonnés en utilisant des piè ges a ` fosse (pitfall traps) faits avec des demi-bouteilles en plastique contenant des agents conservateurs a ` base d'e ´thylè ne glycol. Pendant les cinq mois d'inventaire, 115 espè ces ont e ´té collectées, appartenant a ` 61 familles et 17 ordres de différ-entes classes : douze Insecta, trois Arachnida, un Chilopoda et un Isopoda. Les ordres d'insectes les plus représentés sont les Coléoptè res (44,42%), les Hyménoptè res (20,86%) et les Lépidoptè res (7,87%), tous compris dans les 3 principaux groupes e ´cologiques des phytophages (41,73%), des zoophages (36,52%) et des omnivores (21,73%). Dans cet e ´cosystè me oasien, parmi les zoophages les plus importants il y a des prédateurs (Coléoptè res) et des parasitoı¨des trè s utiles dans la lutte biologique; les Diptè res ou les Hyménoptè res. Quoi qu'il en soit, en dépit du grand nombre des espè ces collectés et les relations existantes entre les différents groupes e ´cologiques, notre e ´tude n'est que le début de la description exhaustive de toute l'entomofaune présente dans les oasis, qui mérite d'e ˆtre poursuivie.

The present study was carried out at the I.T.D.A.S. station (Ain Ben, Biskra), it consists on a contribution to the knowledge of the Ziban oasis arthropods. During the study (2013-2014), every seven days, arthropods were collected using five methods: pitfall traps, yellow water traps, collecting net, light traps and direct hunting. The sample was composed of 2 647 individuals belonging to 18 orders, 69 families and 127 species. The results showed a predominance of the Coleoptera order with 27especes followed by Hymenoptera order with 16 species, Hemiptera order with 15 species and Lepidoptera order with 13especes. A qualitative and quantitative analysis of species identified was done using the different ecological indices and data processing software R.

La phoeniciculture constitue l'une des principales activités agricoles de la wilaya de Biskra ; elle assure non seulement la production de dattes, mais elle est aussi un stimulant du commerce dans la région en amont et en aval ; elle joue également le rôle de couvert végétal pour beaucoup d'espèces cultivées en intercalaire. Les différentes spéculations pratiquées au niveau de nos oasis subissent diverses attaques : les insectes, les maladies, les rongeurs et, spécialement, les adventices. L'infestation des plantations par ces dernières causent des dégâts importants et engendrent des pertes de production. De ce fait, les fellahs tentent continuellement de lutter contre ces plantes concurrentes, soit par les pratiques culturales, soit par les moyens physiques et surtout par la méthode chimique. Cette dernière, plus fréquemment utilisée, n'est souvent pas efficace et constitue un facteur de pollution pour l'environnement.

Dans les oasis de Ziban, cinq stations qui se caractérisent par la haute qualité
des dattes produites ont été inventoriées afin d’étudier les relations entre
l’écosystème oasien et l’entomofaune qui y habite. Les exemplaires ont été
échantillonnés en utilisant des pièges à fosse (pitfall trap) faits avec des demibouteilles en plastique contenant des agents conservateurs à base d’éthylène.
Pendant cinq mois d’enquête, 115 espèces ont été collectées, appartenant à 61
familles et 17 ordres de différentes classes : douze Insecta, trois Arachnida, un
Chilopoda et un Isopoda. Les ordres d’insectes les plus représentés son les
Coléoptères (44,42%), les Hyménoptères (20,86%) et les Lépidoptères
(7,87%), tous compris dans les 3 principaux groupes écologiques des
phytophages (48,98%), des zoophages (26,75%) et des omnivores (24,26%).
Dans cet écosystème oasien, parmi les zoophages les plus importants il y a des
prédateurs (Coléoptères) et des parasitoïdes très utiles dans la lutte biologique
contre les Diptères ou les Hyménoptères. Quoi qu’il en soit, en dépit du grand
nombre d’exemplaires collectés et de la démonstration de l’existence de
relations entre les différents groupes écologiques, notre étude n’est que le
début de la description exhaustive de toute l’entomofaune  présente dans l’oasis
Mots clés: Ecosystème, insectes, oasis de Ziban, inventaire, groupes écologiques.

Algerian steppes are now experiencing a sharp decline resulting in an ecological imbalance and decreased pastoral performance. Based on surveys conducted in the study region in 2015, an inventory of spontaneous plant species was carried out, using the linear method, the pastoral local inventoried taxa in three selected sites revealed a richness of 45 flora species belonging to 41 genera and 26 families. Among the most represented families, Chenopodiaceae with 5 species (11.11%), Fabaceae and Brassicaceae with 4 species for each (8.88%), followed by Asteraceae, Lamiateaeand Zygophyllaceae with 3 species for each (6.66%). The 10 other Families are represented by only one species (2.22%). 31 of the 45 sampled species are perennial and 14 Acheb (annual). The abundance of flora is deferent for the same species from one site to another. The bio-morphological forms are noted, the chamaephytes are more dominant with 21 species (46%).

This work deals with the physico-chemical quality of groundwater intended for irrigation and the prediction of their salinity in the mid-western Cheliff plain. Under a semi-arid climate, irrigation is unavoidable for most crops. As a result, groundwater is under increasing pressure. In addition to the quantitative problem, water quality does not always comply with irrigation standards as defined by individual schools.  The evaluation of the quality of these waters was carried out by analyzing 63 boreholes, the aim of which was to find out their irrigation skills. A study on the spatial variation of electrical conductivity was carried out by applying geostatics, the spatial structure of which is determined by studying the variogram, three classes of salinity were found in this plain; (C3) medium quality; (C4) poor quality; and a quality not recommended for irrigation (C5). Water salinity maps were mapped using Arcgis software10.2. The mapping of the salinity of water by ordinary kriging has shown that the class (C3) largely dominant in the plain, It is a class qualified as very high salinity to be used with great care because it has an effect on the soil and the plant, However, the mapping of this salinity by multiparametric geostatistics allowed us to geolocate the location of the three groups in the study area.

Description of the subject: Remote sensing is an important tool for studying soil characteristics, such as salinity and for monitoring changes in land cover and land use. Objective: This study aims to examine the applicability of Landsat imagery data for soil salinity prediction in El Ghrous palm groves and for the detection of land-use changes that occurred between 2009 and 2017. Methods: Two methods were assessed for the detection of salty soils, the first one; use of spectral indices, which are derived from the Landsat 8OLI satellite image and second one, is application of a non-parametric supervised classification for the detection of changes in land. Results: Combinations between image data and field measurements show that there is not significant correlation.Landsat imagery has shown that the study area has different soil cover units. The superposition map produced indicated major changes in the class of vegetable crops under cover (plasticulture), and a decrease in the surface of salty grounds 9% to 5% during this period. Conclusion: The results of this study explain the expansion in land use mainly for the plasticulture sector and show the advantage of agricultural land development project. Description du sujet : La télédétection est un outil important pour l'étude des caractéristiques du sol, telles que la salinité, et pour la surveillance des changements dans la couverture et l'utilisation des sols. Objectifs : Cette étude vise à examiner l'applicabilité des données d'imagerie Landsat pour la prévision de la salinité des sols dans les palmeraies El Ghrous et pour la détection des changements d'affectation des sols survenus entre 2009 et 2017. Méthodes : Deux méthodes ont été évaluées pour la détection des sols salins, la première : l'utilisation d'indices spectraux dérivés de l'image satellite Landsat 8OLI et la seconde, l'application d'une classification non paramétrique supervisée pour la détection des changements des terres. Résultats : Les combinaisons entre les données d'images et les mesures sur le terrain montrent qu'il n'y a pas de corrélation significative.l'imagerie Landsat a montré que la zone d'étude a différentes unités de couverture du sol. La carte de superposition produite indique des changements majeurs dans la classe des cultures légumières sous abri (plasticulture), et une diminution de la surface des sols salins de 9 à 5 % durant cette période. Conclusion : Les résultats de cette étude expliquent l'expansion de l'utilisation des terres principalement pour le secteur de la plasticulture et montrent l'avantage du projet de développement des terres agricoles.

Description of the subject: Remote sensing is an important tool for studying soil characteristics, such as salinity and for monitoring changes in land cover and land use. Objective: This study aims to examine the applicability of Landsat imagery data for soil salinity prediction in El Ghrous palm groves and for the detection of land-use changes that occurred between 2009 and 2017. Methods: Two methods were assessed for the detection of salty soils, the first one; use of spectral indices, which are derived from the Landsat 8OLI satellite image and second one, is application of a non-parametric supervised classification for the detection of changes in land. Results: Combinations between image data and field measurements show that there is not significant correlation.Landsat imagery has shown that the study area has different soil cover units. The superposition map produced indicated major changes in the class of vegetable crops under cover (plasticulture), and a decrease in the surfac...

Description of the subject: Remote sensing is an important tool for studying soil characteristics, such as salinity and for monitoring changes in land cover and land use. Objective: This study aims to examine the applicability of Landsat imagery data for soil salinity prediction in El Ghrous palm groves and for the detection of land-use changes that occurred between 2009 and 2017. Methods: Two methods were assessed for the detection of salty soils, the first one; use of spectral indices, which are derived from the Landsat 8OLI satellite image and second one, is application of a non-parametric supervised classification for the detection of changes in land. Results: Combinations between image data and field measurements show that there is not significant correlation.Landsat imagery has shown that the study area has different soil cover units. The superposition map produced indicated major changes in the class of vegetable crops under cover (plasticulture), and a decrease in the surfac...

Chestnut cultivation is a type of traditional centennial exploitation in southern areas of Extremadura. Currently, chestnut is in danger of extinction due to the effects of climate change, some diseases (e.g. Cryphonectria parasitica) and land mismanagement. The high temporal variability of rainfall leads to soil erosion in chestnut cultivation. New forms of management are proposed to try, among other things, to reduce soil losses. This study quantifies soil losses in areas under tree canopies and open areas considering two different age plantations; 1990s and 1960s. To achieve the proposed goal 18 erosion plots were installed as paired plots under tree canopies and open areas in both plantations. The total amount of rainfall per event, tree cover, bare soil, runoff coefficient and sediment concentration were also measured in every plot. The results showed that the highest percentage of bare soil (> 45%) coincides with the period of greatest tree cover (> 75%). The open areas ...