نتایج جستجو برای: soil moisture content
تعداد نتایج: 592806 فیلتر نتایج به سال:
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...
The measurement and control of soil moisture are the key technologies of precision agriculture. In order to real-time detect soil moisture content faster and more accurately, a portable soil moisture sensor based on NIR spectroscopy was developed. With the sixty soil samples collected from a winter jujube orchard, a linear regression model was established. The determination coefficients of the ...
Soil moisture is one of the most important variable that in uences the soil-vegetation-atmosphere uxes. However, due to its high temporal and spatial variability, it is dif cult to provide accurate quantitative information on soil moisture at regional and global scales. Different approaches exist, but remote sensing is the more appropriated to measure soil moisture values and its variations. It...
Retrieving information from remotely sensed data is an important task. In the present work, data of L band microwave radiometer has been used to collect the brightness temperature over bare and vegetated fields in two polarizations at different moisture levels. Artificial neural network (ANN) trained with Levenberg-Marquardt algorithm has been used to determine soil moisture from brightness tem...
The grey-brown alluvial soil is a typical soil in the Northern China. It was selected as research object to reveal feasibility and possibility of real-time analyzing soil parameter with NIR spectroscopic techniques. 150 samples were collected from a winter wheat farm. And then the NIR absorbance spectra were rapidly measured under the original conditions by a Nicolet Antaris FT-NIR analyzer. Th...
Airborne remote sensing provides a viable option for high resolution mapping of nearsurface soil moisture that allows larger areas to be covered in greater spatial and temporal detail than has hereto been possible from traditional ground based techniques. However, the current retrieval algorithms require information on near-surface soil temperature and vegetation water content in order to estim...
Ecologists have long classified Midwestern prairies based on compositional variation assumed to reflect local gradients in moisture availability. The best known classification is based on Curtis' continuum index (CI), calculated using the presence of indicator species thought centered on different portions of an underlying moisture gradient. Direct evidence of the extent to which CI reflects di...
Half-lives (t1/2) of two soil incorporated s-triazines (atrazine and prometon) and two thiocarbamate (EPTC and triallate) herbicides were determined in relation to soil moisture content in two California soils. Treated soils were incubated at three moisture levels in aerated glass vials at 25 +/- 1 degree C and were analyzed at 0, 7, 16, 28, 56 and 112 day intervals. Loss of herbicides in all t...
While it is well known that soil moisture directly affects microbial activity and soil organic matter (SOM) decomposition, it is unclear if the presence of plants alters these effects through rhizosphere processes. We studied soil moisture effects on SOM decomposition with and without sunflower and soybean. Plants were grown in two different soil types with soil moisture contents of 45% and 85%...
Hydraulic conductivity is an important parameter in the design of geotechnical structures such as earth dam, floor construction, retaining walls and environmental structures. In unsaturated soils, hydraulic conductivity is a function of moisture content and soil water suction i.e. soil moisture characteristic curve. In this study, the values of unsaturated hydraulic conductivity in two soil typ...
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