depth of frost penetration is one of the main indices in agriculture, civil and transportation engineering. soil temperature is a function of several factors including: topography, solar radiation, air temperature, moisture content and other physical properties of soil such as thermal capacity, coefficient of heat conductivity, and specific heat. the main objective of the present paper is to de...

BACKGROUND AND AIMS The timing of flowering and summer dormancy induction plays a central role in the adaptation of Mediterranean geophytes to changes in the length of the growth season along rainfall gradients. Our aim was to analyse the role of the variation in the responses of flowering and summer dormancy to vernalization, daylength and growth temperature for the adaptation of Poa bulbosa, ...

knowledge about low flow statistics is essential for effective water resource planning and management in ungauged orpoorly gauged catchment areas, especially in arid and semi-arid regions such as iran. we employed a data set of 20 riverflow time-series from the iranian central plateau river basin, iran to evaluate the low-flow series using several frequencyanalysis methods and compared the resu...

in arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. a study was done to analyze the effects of grazing on plant species diversity and plant functional types‘ (pfts) diversity of arid and semi-arid rangelands. we analyzed plant richness and diversity data from 75 sa...

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...

Hypotheses about the origin of vegetation pattern formation in semi-arid areas around the world almost all include a common feature of semi-arid areas: the presence of a positive feedback between plant density and water infiltration. We investigate whether this positive feedback and the spatial redistribution of runoff water are sufficient to explain vegetation pattern formation. For this purpo...

Streamflow in arid and semi-arid regions tends to be dominated by rapid responses to intense rainfall events. Such events frequently have a high degree of spatial variability, coupled with poorly gauged rainfall data. This sets a fundamental limit on the capacity of any rainfall-runoff model to reproduce the observed flow. The IHACRES model is a parameterically efficient rainfall-runoff model t...

the part of precipitation that directly meets the water requirements of a plant, is termed the effective rainfall. effective rainfall estimation methods consist of: direct measurement, empirical methods, and soil-water balance modeling. due to the high costs of measurements and storing devices such as lysimeter, empirical and balance methods are most commonly used to estimate the effective rain...