Evaluation participative de la dégradation des parcours d’El Hadra (province de Rhamna)

The degradation of the El Hadra rangeland was approached by exploring user’s perception and by a technical study which concerned both the vegetation and the substrate. Results show that the users' perception is very rich. The breeders recognize that their rangeland is much degraded. This deterioration is mainly due to their actions and partly to the climatic conditions. The study of the vegetation confirmed the breeders finding. The results show that the plant cover is much degraded. The floristic composition is dominated by annuals. The overall vegetation covert is around 20 to 30% during seasonal growth. The density of vegetation is very high and mainly consists of annuals, explaining the strong seasonality of this rangeland. Dry matter production, composed by a large part of perennials species, is variable depending on the substrate; it is 700 to 1000 kg DM / ha for heavy and less stony soils and 350 to 500 kg DM per hectare for calcareous and stony soils.L’état actuel de dégradation des parcours d’El Hadra a été approché par l’exploration de la perception des usagers et par une étude technique qui a concerné aussi bien la végétation que le substrat. Les résultats montrent que la perception des usagers est très riche. Les éleveurs reconnaissent que leur parcours est très dégradé. Cette dégradation est due surtout à l’action humaine et en partie aux conditions climatiques.L’étude de la végétation a confirmé le constat des éleveurs. Les résultats montrent que le couvert végétal est très dégradé. La composition floristique est dominée par les annuelles. Le recouvrement global de la végétation est de l’ordre de 20 à 30% en pleine période de croissance de la végétation. La densité de la végétation est très élevée et composée essentiellement d’annuelles, ce qui explique la forte saisonnalité de ce parcours. La production en matière sèche est variable selon le substrat, elle est de 700 à 1000 kg de MS/ha pour les sols lourds et moins caillouteux et de 350 à 500 kg de MS à l’hectare pour les sols calcaires et caillouteux, composée en grande partie des pérennes

Resistance source to cowpea aphid (Aphis craccivora Koch) in broad bean (Vicia faba L.) Algerian landrace collection

The present study evaluated the resistance of 7 varieties of the broad bean Vicia faba L. to cowpea aphid, Aphis craccivora Koch, 1854. These landraces from the region of Biskra (in the south of Algeria)were selected in an initial field trial and subjected to further testing in the greenhouse. Landrace V51 proved to be the most interesting, in that it resisted aphid attack by mechanisms involving toleranceand antibiosis. Aphid infestation of this landrace resulted in a dry weight loss of only 3.09% (comparison with uninfested plants). The antibiotic resistance of this landrace also significantly decreased the biological potential of the cowpea aphid. In addition to the agronomic and heritage value, some of the landraces of the Biskra region displayed tolerance and antibiosis characteristics suggesting that they might serve as an important genetic resource in future bean selection programs. All tested landraces are attractive to A. craccivora but only this preference is marked more for varieties V23 and V24

Resistance source to cowpea aphid (Aphis craccivora Koch) in broad bean (Vicia faba L.) Algerian landrace Collection

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceThe present study evaluated the resistance of 7 varieties of the broad bean Vicia faba L. to cowpea aphid, Aphis craccivora Koch, 1854. These landraces from the region of Biskra (in the south of Algeria) were selected in an initial field trial and subjected to further testing in the greenhouse. Landrace V51 proved to be the most interesting, in that it resisted aphid attack by mechanisms involving tolerance and antibiosis. Aphid infestation of this landrace resulted in a dry weight loss of only 3.09% (comparison with uninfested plants). The antibiotic resistance of this landrace also significantly decreased the biological potential of the cowpea aphid. In addition to the agronomic and heritage value, some of the landraces of the Biskra region displayed tolerance and antibiosis characteristics suggesting that they might serve as an important genetic resource in future bean selection programs. All tested landraces are attractive to A. craccivora but only this preference is marked more for varieties V23 and V2

A Zero-Index Metamaterial Single Layer Superstrate for Patch Antenna Gain Enhancement

The objective of this paper is to use a zero refractive index n metamaterial as single layer superstrate suspended above a microstrip patch antenna (MPA), operating at 43 GHz, for the gain enhancement. The single metamaterial layer superstrate is composed of a periodic arrangement of Jerusalem cross unit-cells, and behaves as an homogeneous medium characterized by a refractive index close to zero. This metamaterial low index property allows gathering radiated waves from the antenna and collimates them towards the superstrate normal direction. The proposed design improves the antenna gain by 5.1 dB

Investigation of the effect of piperidin-1-yl-phosphonic acid on corrosion of iron in sulfuric acid

The inhibitive effect of the piperidin-1-yl-phosphonic acid (PPA) on the corrosion of iron in 1 M H2SO4 solution has been investigated by weight loss measurement, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The presence of (PPA) reduces remarkably the corrosion rate of iron in acidic solution. The effect of temperature on the corrosion behavior of iron was studied in the range of 298–328 K. Results clearly reveal that the (PPA) behaves as a mixed type corrosion inhibitor with the highest inhibition at 5 × 10−3 M. The adsorption of PPA on the iron surface obeys the Langmuir's adsorption isotherm

Population dynamics of cattle ticks in Gharb Region in Morocco

This study was conducted in the rural town of Sidi Boubker El Haj in Gharb Region, Morocco, from November 2009 to October 2010. The objective was to identify the various tick species collected on cattle, to monitor their seasonal dynam­ics and determine their abundance and infestation variability according to the age and sex of the hosts. Thirty cattle head were monitored and sampled monthly for a year. A total of 6899 ticks were collected. Identification revealed nine species belonging to five genera with the following prevalence: Rhi­picephalus bursa 28.61%, Ixodes ricinus 26.39%, Hyalomma lusitanicum 23.33%, Rhipicephalus turanicus 14.44%, Hya­lomma detritum detritum 13.06%, Rhipicephalus sanguineus 1.39%, Hyalomma marginatum marginatum 1.11%, Derma­centor marginatus 1.11% and Haemaphysalis sulcata 0.83%. I. ricinus was active in winter, R. bursa, Hyalomma lusitanicum and R. turanicus in spring, and Hyalomma d. detritum in sum­mer. R. sanguineus, Hyalomma m. marginatum, D. margina­tus and Haemaphysalis sulcata were less prevalent and their presence on cattle may be referred to as occasional parasitism. This study on tick population dynamics may help implement a strategy for tick control and tick-transmitted disease control, taking into account the parasite seasonal activity, parasitic loads, and infestation rates