نتایج جستجو برای: subsurface soil

تعداد نتایج: 194045  

2015
Yohei Sawada Toshio Koike Jeffrey P. Walker

Despite the importance of the coupling between vegetation dynamics and root-zone soil moisture in land-atmosphere interactions, there is no land data assimilation system (LDAS) that currently addresses this issue, limiting the capacity to positively impact weather and seasonal forecasting. We develop a new LDAS that can improve the skill of an ecohydrological model to simulate simultaneously su...

1998
Robert S. Kerr Eva L. Davis

Innovative technologies for subsurface remediation, including in situ techniques based on heating the subsurface to enhance the recovery of organic contaminants, are increasingly being evaluated for use at specific sites as the limitations to the conventionally-used techniques are recognized. The purpose of this Issue Paper is to provide to those involved in assessing remediation technologies f...

Journal: :Ecological applications : a publication of the Ecological Society of America 2009
V Bala Chaudhary Matthew A Bowker Thomas E O'Dell James B Grace Andrea E Redman Matthias C Rillig Nancy C Johnson

Communities of plants, biological soil crusts (BSCs), and arbuscular mycorrhizal (AM) fungi are known to influence soil stability individually, but their relative contributions, interactions, and combined effects are not well understood, particularly in arid and semiarid ecosystems. In a landscape-scale field study we quantified plant, BSC, and AM fungal communities at 216 locations along a gra...

2003
C. A. Cambardella T. B. Moorman D. B. Jaynes J. L. Hatfield T. B. Parkin W. W. Simpkins D. L. Karlen

Nonpoint source contamination of surface and groundwater resources with nitrate-N (NO3-N) has been linked to agriculture across the midwestern USA. A 4-yr study was conducted to assess the extent of NO3-N leaching in a central Iowa field. Water flow rate was monitored continuously and data were stored on an internal datalogger. Water samples for chemical analysis were collected weekly provided ...

2017
P. Singh Ramesh S. Kanwar K. E. Johnsen Lajpat R. Ahuja R. S. Kanwar L. R. Ahuja

This study was designed to calibrate and evaluate the subsurface drain flow component of the Root Zone Water Quality Model (RZWQM; Version 2.5) for four tillage-systems: chisel plow (CP), moldboard plow (MB), no-tillage (NT), and ridge-tillage (RT). Measured subsurface drain flow data for 1990 was used for model calibration. Main parameters calibrated were lateral saturated hydraulic conductivi...

ژورنال: علوم آب و خاک 2019

Subsurface drip irrigation systems, compared to other irrigation systems (basin and furrow), enhance the delivery of water and nutrients directly into the root zone. The purposes of this study were to determine wetting front advancement in a subsurface drip irrigation and to compare the results with the HYDRUS 2D model simulation. In this study, the irrigation using T-Tape was carried out on a ...

The aim of this research was to study how water use management can increases vegetation cover inrainwater catchment systems. The study was conducted through comparison of two methods of irrigation, i.e. traditional sub-surface drip irrigation and drip irrigation. Three soil samples were taken and analyzed from three locations in north of Sistan from a depth of 50 cm. A furrow was dug with a bas...

2006
Wei Zheng Scott R. Yates Sharon K. Papiernik Joe Nunez

Metam sodium is the most widely used soil fumigant in the United States. The primary breakdown product of metam sodium in soil is methyl isothiocyanate (MITC), an active pesticidal agent with a high toxicity and a great potential for volatilization. Reducing atmospheric emissions of MITC is therefore critical to maintain air quality. The objective of this study was to examine the rate and effic...

Journal: :Journal of environmental quality 2001
R W McDowell A N Sharpley

Phosphorus application in excess of crop needs has increased the concentration of P in surface soil and runoff and led many states to develop P-based nutrient management strategies. However, insufficient data are available relating P in surface soil, surface runoff, and subsurface drainage to develop sound guidelines. Thus, we investigated P release from the surface (0-5 cm depth) of a Denbigh ...

2000
Ed. Chen D. C. CHIN ROBERT E. BALL

The Electrical Conductivity Object Locator (ECOL) has been developed with the goal of detecting buried objects. Its specific capability to detect and characterize small-size plastic and metal objects buried at shallow depths is demonstrated. The technique can also detect larger objects at greater depths. The ECOL technique maps the soil subsurface conductivity and identifies variations in the c...

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