this study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. the study was carried out in steppe rangelands of saveh, markazi province, iran. four sites with four grazing intensities including very high, high, moderate and non-grazed with the same ecological conditions were selected. to study various vegetation and...

Genetic variation for potentially adaptive traits of the key restoration species Sandberg bluegrass (Poa secunda J. Presl) was assessed over the intermountain western United States in relation to source population climate. Common gardens were established at two intermountain west sites with progeny from two maternal parents from each of 130 wild populations. Data were collected over 2 years at ...

A brief analysis on the distribution range of some of the species dominating in the arid and extra arid regions of North Africa and Arabian Peninsula is presented. These species are belonging to three phytogeographical categories namely: Saharo-Sindian, Sudano-Deccanian and Tropical African-Indian elements. Species included for this study are either disjunct or they have a wider distribution, s...

On July 17, 2003, the National Bureau of Economic Research announced that the United States economy had troughed in November 2001 following the peak in March 2001. This makes the 2001 recession one of the shortest in U.S. history being only eight months in length. Whereas business cycles are defined in terms of the overall economies the authors of this paper investigate whether this national re...

Cynara cardunculus.L exhibits an important adaptability to arid and semi-arid regions where high salinity is frequently present. Aiming to introduce its cultivation in the Mediterranean environment especially in Tunisia, it seemed interesting to study seed germination of eight populations of cardoon in four concentrations of NaCl: 0g/L, 2g/L, 4g/L, and 8g/L. Our results showed a good variabilit...

Arid and semi-arid areas occupy one third of the total area of the world. This vast region is rich in natural resources. In recent times, desertification has become a world-wide phenomenon, due to human activities. China also suffers from this problem. Desertification is especially severe in the southeastern part of the arid and semi-arid region of the country. In this paper, the use of remote ...

Riparian zones in semi-arid regions often exhibit high rates of evapotranspiration (ET) in spite of low soil moisture content due to vegetation that is able to withdraw water from shallow aquifers. This work better defines the relationship between ET and the saturated zone by comparing the observed water table drawdown to analytically modeled drawdown in fully penetrating wells of an unconfined...