This investigation was carried out during the period extended from spring 2011 to autumn 2012 at Sidi-Barrani in the North Western Coast of Egypt under rainfed conditions. The objective of this investigation was to study the natural vegetation qualitatively and quantitatively in relation to the effect of some ecological factors, i.e., plant communities and growth seasons on some range measurements, i.e., botanical composition, plant density, coverage, frequency, importance value, foliage yield and nutritive value of some perennial species. Thirty-eight plant species belonging to 16 families were found; the highest number of plant families, number of plant species and palatable plant species were obtained under Artemisia herba-alba community. The highest values of plant density, coverage % and forage yield were recorded under A. herba-alba community in spring season during both years. Meanwhile, the lowest values of all studied traits were recorded under Anabasis articulata community in autumn season.Significant differences were found between plant communities, growth seasons and their interaction.Among perennial species, the highest figure of importance value (IV) was contributed by A. articulata, A. herba-alba and Gymnocarpos decandrum in both years. While, Trigonella stellata and Aegilops kotschyi have the highest values (IV) among the annual species in the first year. Meanwhile, Hippocrepis bicontorta, Scorpiurus muricatus gave the highest (IV) during spring season in the second year.Highest digestible crude protein percentage (DCP) was recorded in Helianthemum lippii species followed by A. herba-alba. The highest TDN % were achieved by Noaea mucronata and G. decandrum. A. herba-alba and H. lippii gave the maximum values of digestible energy (DE), metabolized energy (ME) and net energy (NE). Deverra tortuosus recorded the highest value of gross energy (GE).ª 2014 Production and hosting by Elsevier B.V. on behalf

Two field experiments were carried out in the Desert Research Center (D.R.C.), Agricultural experimental station at El-Kharga, New Valley Governorate, during two growing seasons of 2005 and 2006, to study the effect of planting dates and plant densities on productivity of cowpea (Vigna Sinensis L., cv. Kareem 7). The soil texture was sandy clay loam containing 2.04 % organic matter, pH 8.3 and EC 4.4 dS/ m. Underground water was the source of irrigation its pH was 7.3 and EC 1.08 dS/ m. Combined analysis of the two seasons data showed the follows: 1-Planting on 15 March as well as the density of 224000 plants / fed. each gave the highest significant values in plant height, number of branches / plant, fresh and dry weight / plant, fresh and dry forage yield/fed, number of pods / plant, number of seeds / plant, seed weight / pod, 100-seed weight, biological yield, seed yield, straw yield and chemical composition such as, nitrogen, phosphorus, potassium, total carbohydrate, crude protein contents and TDN % in seeds and straw of cowpea plants. 2-The interaction between planting date and plant density had a significant effect on plant height, number of branches / plant, fresh and dry weight / plant, fresh and dry forage yield/fed, number of pods / plant, number of seeds / plant, seed weight / pod, 100-seed weight, biological yield, seed yield and straw yield. The highest values were obtained by planting on 15 March with the density of 224000 plants / fed. while the reverse were obtained by planting on 15 February with 84000 plants / fed. Planting on 15 March increased all chemical characters i.e., nitrogen, phosphorus, potassium, total carbohydrate and crude protein contents of cowpea plants under planting density of 224000 plants / fed., except TDN % of straw which gave the highest value by planting in1 st March with 224000 plant / fed.

Seasonal variations in climatic factors have a great effect on growth parameters of most plant species. The importance of the recent investigation is to evaluate the grazing value and availability of development the desirable plants for feeding livestock around the year and its relationship with climatic factors. Therefore, this study was carried out in 1998/1999 -1999/2000 to make survey to the plant vegetation at wadi El Natron -El Almeen road (East Marsa Matrouh) at 5 sites in that area. every wet and dry season to evaluate the vegetation structure throughout 25 chart quadrates (5*5m 2 each ) . Correlation coefficient between some climatic factors (rainfall, temperature, and evaporation) and each of the different vegetation parameters within each of the vegetation types was calculated.The results showed that most of the pasture measurements such as coverage %, Frequency %, Abundance %, fresh and dry production (Ton/fed.) reached their maximum during dry seasons except plant density (plant/m 2 ) was greater in wet seasons. The results indicated that fifteen species belonging to eleven families were found. The majority of these species were perennial plants. Anabasis articulate and Thymelaea hirsuta were highest dominnet comparing the other plants to its adaptability to dry conditions.Generally, positive correlation between rainfall and each of annual palatable species was found, adversely, temperature take an opposite trend, incase of unpalatable and perennial species, each of the climatic factors had variable effect on each of the vegetation measurements.