Susceptibility of twelve soft wheat varieties (Triticum aestivum) to Sitophilus granarius (L.) (Coleoptera: Curculionidae)

International audienceThe aim of study is the effect of trophic medium of twelve soft wheat varieties on the biotic potential of S.granarius L. After 3 months of storage under laboratory conditions at 27 ± 2 ° C and 70 ± 5% rh, have reveals that the preferred varieties for development of this species are Hidhab, Mahon Demias, Arfort and Siete Ceros. This latest was found to be the most susceptible. Growth index and loss were highest with 2.08 and 3.27% respectively. Laboratory analysis of the main grain components of the different varieties suggested that the susceptibility of these varieties to S. granarius infestation may be attributed to the high content of protein and low content of carbohydrate compared to resistance varieties

Assessment of nutrient contamination in surface water, case study of Ain Zada Dam (North-East of Algeria)

In order to evaluate the impact of potential pollutions on the water quality in the watershed of the upstream of wadi Boussellem (North-east of Algeria), the evolution of the chemical composition of waters of the Ain Zada dam was studied over a period of ten years. Using a linear  model  of  trends and a  principal  components  analysis  (PCA)  methods,  have  been detected and quantified for the substances that are connected with the fertilizers and domestic effluents. An increasing concentration is observed for most of these substances. The increase of 88% in COD, 66% in BOD5  and the decrease of 4.3% in pH, suggests a degradation of O.M 85% by microorganisms. This degradation was accompanied by a decrease of 2% of O2dis  content. The large increases of E.C 76%, NH4  290% and NO2  100%, are related to a marked  increase  in  fertilizers  applications  and  the denitrification  of NO3  where  latters declined by 77%. These increases are related also to the large amount of human and animal organic materials and industrial waste dumped.Keywords: Pollution; Eutrophication; wadi Boussellem; microorganisms, fertilizer

Operating Systems of the Meadows in Semi-Arid Region of Algeria

Permanent meadows are the base of the fodder resources and also provide environmental services (MAP France, 2002). The function of fodder production is no longer solely to ensure bulk agricultural production. It must also allow the development of livestock products of good quality, contribute to environmental protection, the quality of the landscape and ensure a viable economic activity in the rural areas. These areas have decreased greatly (from 1 million ha at the beginning of the century (Lapeyronie, 1982) to less than 300,000 ha in 2000), in particular in the semi-arid zones at high altitude; however they contribute very effectively to natural diversity and the fight against desertification (Faye & Alary, 2001). The lack of a global solution to agricultural development and the intensification of production in certain sectors (cultivation of cereals) have induced a continued loss of meadow areas. This paper is the first study of the diversity of production systems comprising natural meadows in a small area of Algeria on a randomly selected sample of farms