نتایج جستجو برای: soil and vegetation
تعداد نتایج: 16870582 فیلتر نتایج به سال:
The ecosite unit in Ontario‘s boreal forest ecological land classification system is a polygon of common vegetation type and soil conditions intended to provide a standardized provincial framework to inform meso-scale forestry and planning applications. To determine whether the physical factors used for ecosite classification relate to patterns in ecological function over finer spatial scales, ...
We discuss a simplifed, conceptual model for the dynamics of the soil-vegetation system in drylands. The model considers the different dynamical processes taking place in vegetated and non-vegetated soil and it distinguishes between the upper soil layer, where rapid evaporation dominates, and the deeper root layer where only plant transpiration takes place. We explore the role of rainfall inter...
Two neural network algorithms trained by a physical vegetation model are used to retrieve soil moisture and vegetation variables of wheat canopies during the whole crop cycle. The first algorithm retrieves soil moisture using L band, two polarizations and multiangular radiometric data, for each single date of radiometric acquisition. The algorithm includes roughness and vegetation effects, but ...
Background and objectives: Mountain habitats, due to their climatic conditions, are considered to be very sensitive areas and generally have less plant diversity compared to the lower elevations. Unfortunately, in the past years, due to human attacks, parts of these areas have been destroyed and now some areas are either devoid of vegetation or have very little vegetation. Since Crataegus and B...
Rangeland vegetation dynamics can be affected by various natural and unnatural factors over time. The purpose of this study was to investigate the dynamics of vegetation under the climatic conditions and soil properties. Accordingly, data collection for evaluating vegetation dynamics in rangeland ecosystems of Ardabil province was conducted at three research sites including Moqan winter rangela...
A multi-layer one-dimensional vertical model of the upper soil, vegetation and lower atmosphere is developed and implemented. This model includes explicit representations of the heat and moisture diffusion both in the soil and in the atmosphere, and computations of various mass and energy fluxes at the soil-air, vegetation-air and soil-root interfaces. Four models are run in parallel to compute...
In this paper, the results of an experiment carried out for exploiting the capabilities of X-band Cosmo-SkyMed data in the monitoring of soil and vegetation characteristics are summarized. SAR data have been collected in two agricultural areas in Italy and compared with ground truth measurements of soil and vegetation parameters. A rather good sensitivity to vegetation features, biomass and the...
Dispersion and transport of Cryptosporidium Oocysts from fecal pats under simulated rainfall events.
The dispersion and initial transport of Cryptosporidium oocysts from fecal pats were investigated during artificial rainfall events on intact soil blocks (1,500 by 900 by 300 mm). Rainfall events of 55 mm h(-1) for 30 min and 25 mm h(-1) for 180 min were applied to soil plots with artificial fecal pats seeded with approximately 10(7) oocysts. The soil plots were divided in two, with one side de...
Multitemporal processing of synthetic aperture radar imagery, e.g. for the extraction of a soil moisture index, requires normalization of acquisitions from different locations in space to a common incidence angle. Incidence angle dependence of backscatter is known to depend on the amount of aboveground vegetation, and can thus be expected to vary seasonally as a result of vegetation phenology. ...
We studied the impacts of re-vegetation on soil moisture dynamics and evapotranspiration (ET) of five land cover types in the Loess Plateau in northern China. Soil moisture and temperature variations under grass (Andropogon), subshrub (Artemisia scoparia), shrub (Spiraea pubescens), plantation forest (Robinia pseudoacacia), and crop (Zea mays) vegetation were continuously monitored during the g...
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