Nutrient value of plants in an extremely arid environment (Wadi Allaqi Biosphere Reserve, Egypt)

The vegetation of Wadi Allaqi is of critical importance to the quality of life of the local nomadic population. Many species are known to be of potential value and use for animal grazing. Eight common species were collected from different parts of Wadi Allaqi in order to evaluate their nutritional status and identify the potential suitability of these species for grazing. Plant samples were analysed for P, K, Na, Ca, Mg, Cl, crude protein, carbohydrates, fibres, fats and secondary products. The results showed that Tamarix nilotica, which forms the major source of livestock grazing due to its dominance around the lake, has a high protein and carbohydrate content and is also a salt accumulator. Astragalus vogelii provides a good source of livestock grazing due to its nutrition value, but only for the short period following the seasonal rain event, while the good quality grazing period of Psoralea plicata was much longer. The grasses, such as Eragrostis aegyptiaca, Fimbristylis bisumbellata, and Crypsis schoenoides, represent the main source of grazing for livestock on the shores of Lake Nasser after the inundation of water. Citrullus colocynthis and Euphorbia granulata are common species all over the wadi and are only grazed by gazelle.