نتایج جستجو برای: soil water uniformity

تعداد نتایج: 705692  

2010
Marko Bertmer Gabriele Schaumann

Water plays a crucial role in soil organic matter (SOM) having various different functions such as transport of material, elution of ,e. g., pollutants in soil, and also the sequestration of humic substances. Furthermore, the generation and quantification of hydrophilic and hydrophobic regions in soil has several effects on SOM which can also include the storage amount and time of certain mater...

2012
Zilong Wang Qiuxiang Jiang Qiang Fu Tianxiao Li

The identification of freezing-thawing soil hydraulic properties is the basis and key problem of studying soil water movement. Current identifying methods of the properties have many limitations, such as big error, high uncertainty and low operability. Thus, the identifying method of freezingthawing soil hydraulic properties was researched in the research. The estimating parameters of soil free...

Journal: :Journal of nematology 1994
R F Davis R D Wauchope A W Johnson

Field and greenhouse experiments were conducted to determine the extent to which fenamiphos and its degradation products, fenamiphos sulfoxide and fenamiphos sulfone, are available to contact nematodes in the soil. Water extraction provided a relative measure of each chemical's availability to the soil water where the chemicals could contact nematodes, and methanol extraction provided a relativ...

Journal: :Journal of experimental botany 2010
Xavier Draye Yangmin Kim Guillaume Lobet Mathieu Javaux

Due in part to recent progress in root genetics and genomics, increasing attention is being devoted to root system architecture (RSA) for the improvement of drought tolerance. The focus is generally set on deep roots, expected to improve access to soil water resources during water deficit episodes. Surprisingly, our quantitative understanding of the role of RSA in the uptake of soil water remai...

Journal: :Tree physiology 2009
Kathleen D Eggemeyer Tala Awada F Edwin Harvey David A Wedin Xinhua Zhou C William Zanner

We used the natural abundance of stable isotopic ratios of hydrogen and oxygen in soil (0.05-3 m depth), plant xylem and precipitation to determine the seasonal changes in sources of soil water uptake by two native encroaching woody species (Pinus ponderosa P. & C. Lawson, Juniperus virginiana L.), and two C(4) grasses (Schizachyrium scoparium (Michx.) Nash, Panicum virgatum L.), in the semiari...

Journal: :Tree physiology 2006
K R Hultine D F Koepke W T Pockman A Fravolini J S Sperry D G Williams

We investigated hydraulic constraints on water uptake by velvet mesquite (Prosopis velutina Woot.) at a site with sandy-loam soil and at a site with loamy-clay soil in southeastern Arizona, USA. We predicted that trees on sandy-loam soil have less negative xylem and soil water potentials during drought and a lower resistance to xylem cavitation, and reach E(crit) (the maximum steady-state trans...

2007
Jianjun Zhou Gang Liu Su Li Xiu Wang Man Zhang

Owing to the difference of soil water in the farm, a system of variable rate irrigation was developed with Visual C++ and MapObjects that can save water as well as can improve economy benefit. Soil water content can be forecasted by using the forecast model of soil water, according to the real soil water content of different sampling sites in this system. Irrigation or not can be decided by com...

2011
Pankaj Sharma Geeta Singh Rana P. Singh

The field experiments were conducted on sandy loam soil at New Delhi, during 2007 and 2008 to investigate the effect of conservation tillage, irrigation regimes (sub-optimal, optimal and supra-optimal water regimes), and integrated nutrient management (INM) practices on soil biological parameters in wheat cultivation. The conservation tillage soils has shown significant (p<0.05) increase in soi...

2014
Wei Ouyang Siyang Chen Guanqing Cai Fanghua Hao

Understanding the fates of soil hydrological processes and nitrogen (N) is essential for optimizing the water and N in a dryland crop system with the goal of obtaining a maximum yield. Few investigations have addressed the dynamics of dryland N and its association with the soil hydrological process in a freeze-thawing agricultural area. With the daily monitoring of soil water content and acquis...

2013
Feng Jiao Zhong-Ming Wen Shao-Shan An

The relationship between vegetation and soil moisture deserves attention due to its scientific importance and practical applications. However, the effects of soil moisture on vegetation development and succession are poorly documented. Here we study soil water storage in Yanhe watershed at northern Shaanxi on five different land uses, namely shrubland, farmland, natural grassland, woodland, and...

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