نتایج جستجو برای: soil cover and soil moisture and bromus tomentellus p
تعداد نتایج: 17053075 فیلتر نتایج به سال:
Current paradigm suggests that spatial and temporal competition for resources limit an exotic invader, cheatgrass (Bromus tectorum L.), which once established, alters fire regimes and can result in annual grass dominance in sagebrush steppe. Prescribed fire and fire surrogate treatments (mowing, tebuthiuron, and imazapic) are used to reduce woody fuels and increase resistance to exotic annuals,...
Using a fully coupled climate–terrestrial ecosystem model, we demonstrate explicitly that an initial perturbation on vegetation induces not only a direct positive vegetation feedback, but also a significant indirect vegetation–soil moisture feedback. The indirect feedback is generated through either fractional cover change or soil moisture depletion. Both indirect feedback mechanisms are trigge...
ABSTRACT- To evaluate effects of different soil moisture conditions namely, phosphorus (P) and zinc (Zn) application, on extractable Zn and Fe, two experiments were conducted in laboratory conditions based on a completely randomized design with a factorial arrangement of treatments with two replications. The first experiment was performed with the following factors; incubation time at four leve...
During the last decade, great progress has been made by the scientific community in generating satellite-derived global surface soil moisture products, as a valuable source of information to be used in a variety of applications, such as hydrology, meteorology and climatic modeling. Through the European Space Agency Climate Change Initiative (ESA CCI), the most complete and consistent global soi...
Soil moisture information is an important factor in the fields of hydrology, meteorology and climatology. For hydrological applications, soil moisture data with a spatial resolution of 1 km is often requested. Current remote sensing methods are limited to a spacial resolution of 25–50 km. This study was motivated by the need to improve the resolution of soil moisture information. The aim was to...
This study was conducted to investigate the effects of soil moisture content on the absorbance spectra of sandy soils with different phosphorus (P) concentrations using ultraviolet (UV), visible (VIS), and near-infrared (NIR) absorbance spectroscopy. Sieve sizes were 125, 250, and 600 m for fine, medium, and coarse, respectively. The medium size of the samples was used for the study. Investigat...
In this research, a back-propagation neural network was used to retrieve and map the surface soil moisture in Oklahoma (97d35'W, 36d15'N) from Synthetic Aperture Radar data acquired by RADARSAT-1 satellite. In addition to SAR backscattering, different vegetation-related information (vegetation optical depth and Normalized Difference Vegetation Index) have been added as additional inputs to the ...
In tundra ecosystems, bryophytes influence soil processes directly and indirectly through interactions with overstory shrub species. We experimentally manipulated moss cover and measured seasonal soil properties and processes under two species of deciduous shrubs with contrasting canopy structures, Salix planifolia pulchra and Betula glandulosa-nana complex. Soil properties (seasonal temperatur...
Accurate land surface process modelling might be limited due to lack of reliable model input data. Key surface variables as land cover information or soil moisture conditions have been proven to be observable by remote sensing systems. The integration of remote sensing data into land surface process models might therefore help to improve their simulations results. Longer wavelength SAR data has...
Seasonal changes over 2 years (2004–2006) in soil moisture content ( v) of frozen alpine frost meadow soils of the QinghaiTibet plateau permafrost region under three different levels of vegetation cover were investigated. Vegetation cover and air temperature changes had significant effects (synergistic effect) on v and its distribution in the soil profile. During periods of soil freezing or tha...
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