نتایج جستجو برای: it causes soil moisture shortage and reduced current waters

تعداد نتایج: 17047266  

Journal: Desert 2009
A. Tavili J. Farzadmehr M. Rostampour m.a Zare Chahouki

Abstract This paper presents a quantitative account of vegetation–environmental factor relationships in arid rangelands. Vegetation cover was recorded using Braun-Blanquet combined abundance-cover scale in each quadrat. Within each quadrat, one profile was dug and soil samples being taken at 0-20cm and 20-100cm depths. Under study physical-chemical characteristics included texture, lime, orga...

2009
Claire Gruhier François Cabot Yann Kerr Patricia de Rosnay Edouard Belin

Soil moisture is one of the most important variables that influences the soil-vegetation-atmosphere fluxes. This is particularly true over the Sahelian region, soil moisture has an important feedback on precipitation. It is particularly difficult to access to soil moisture values because its high temporal and spatial variability. Different approaches exist, but microwave remote sensing is the m...

2001
JEFFREY P. WALKER GARRY R. WILLGOOSE JETSE D. KALMA

The Kalman filter assimilation technique is applied to a simplified soil moisture model for retrieval of the soil moisture profile from near-surface soil moisture measurements. First, the simplified soil moisture model is developed, based on an approximation to the Buckingham–Darcy equation. This model is then used in a 12month one-dimensional field application, with updating at 1-, 5-, 10-, an...

2010
M. Choi H. Kim

Passive microwave sensors have many advantages including the ability to directly measured soil moisture at large spatial scales regardless of weather conditions or time of day. However, microwave-sensed soil moisture’s inevitable limitation is that it cannot describe hydrology at the watershed because its retrieved soil moisture scale is too large. Thus, microwave-sensed soil moisture requires ...

2015
Yuan Huang Yongdong Wang Ying Zhao Xinwen Xu Jianguo Zhang

Salinization and secondary salinization often appear after irrigation with saline water. The Taklimakan Desert Highway Shelterbelt has been irrigated with saline ground water for more than ten years; however, soil salinity in the shelterbelt has not been evaluated. The objective of this study was to analyze the spatial and temporal distribution of soil moisture and salinity in the shelterbelt s...

2011
G. W. Moore J. A. Jones B. J. Bond

The water balance equation dictates that streamflow may be reduced by transpiration. Yet temporal disequilibrium weakens the relationship between transpiration and streamflow in many cases where inputs and outputs are unbalanced. We address two critical knowledge barriers in ecohydrology with respect to time, scale dependence and lags. Study objectives were to correlate components of the water ...

Journal: :Global change biology 2014
Zachary A Sylvain Diana H Wall Karie L Cherwin Debra P C Peters Lara G Reichmann Osvaldo E Sala

Climate change will result in reduced soil water availability in much of the world either due to changes in precipitation or increased temperature and evapotranspiration. How communities of mites and nematodes may respond to changes in moisture availability is not well known, yet these organisms play important roles in decomposition and nutrient cycling processes. We determined how communities ...

2016
L. Hao G. Sun Y.-Q. Liu G. S. Zhou J. H. Wan L. B. Zhang J. L. Niu Y. H Sang J. J. He

Precipitation, evapotranspiration (ET), and soil moisture are the key controls for the productivity and functioning of temperate grassland ecosystems in Inner Mongolia, northern China. Quantifying the soil moisture dynamics and water balances in the grasslands is essential to sustainable grassland management under global climate change. We conducted a case study on the variability and character...

Journal: :Tree physiology 2011
S Polverigiani M L McCormack C W Mueller D M Eissenstat

In woody plants, pioneer roots are the main roots used to expand the root system horizontally and vertically whereas fibrous 'feeder' roots are chiefly used in the absorption of water and nutrients. Because of their different roles, we expected newly emerged pioneer and fibrous roots to respond differently to restrictions in soil moisture. We hypothesized that fibrous roots would exhibit greate...

1999
T. C. Todd J. M. Blair G. A. Milliken

Climate change predictions for the Great Plains region of North America include reduced growing season precipitation. The consequence of this prediction for soil fauna and belowground processes was investigated at two spatial scales by integrating experimental manipulation of soil moisture levels with natural variation in soil-water availability. Experiments consisted of (1) reciprocal core tra...

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