نتایج جستجو برای: surface soil

تعداد نتایج: 797336  

2012
Du Changwen Zhou Jianmin Keith W. Goyne

Paddy soils are classified as wetlands which play a vital role in climatic change and food production. Soil carbon (C), especially soil organic C (SOC), in paddy soils has been received considerable attention as of recent. However, considerably less attention has been given to soil inorganic carbon (SIC) in paddy soils and the relationship between SOC and SIC at interface between soil and the a...

2003
W. J. Parton Melannie Hartman

The potential sensitivity of ecological models to differences in soil temperature and soil water from land-surface models was evaluated by using model output from the PILPS land-surface model comparison. Simulated soil water and temperatures from the land-surface models were used to calculate the abiotic decomposition factor (ADF). ADF is used by ecosystem models to directly control microbial a...

2007
C. W. Ross R. E. Sojka J. A. Foerster

Polyacrylamide (PAM) is used at rates of i to 2 kg ha per irrigation on a half million hectares of United States irrigated farmland to prevent 94% of irrigation-induced erosion and to enhance infiltration by i5% to 5o% on medium to fine-textured soils. The polyacrylamides used for this application are large (i2 to i5 megagrams per mole), water-soluble anion molecules applied in the irrigation s...

ژورنال: علوم آب و خاک 2019

Long-term use of treated wastewaters for irrigation adds compounds and/or ions to soils which might alter the soil physical, hydraulic and mechanical properties. Soil mechanical properties are closely linked with the plant growth. This study was conducted to investigate the effect of short-, mid- and long-term applications of the treated wastewater of Mobarake Steel Company in Isfahan on the so...

2010
Y. Y. Liu J. P. Evans M. F. McCabe

Vertisols are clay soils that are common in the monsoonal and dry warm regions of the world. One of the characteristics of these soil types is to form deep cracks during periods of extended dry, resulting in significant variation of the soil and hydrologic properties. Understanding the influence of these varying soil properties on the hydrological behavior of the system is of considerable inter...

Journal: :Journal of environmental quality 2012
Ana R García Roberto Maisonnave Marcelo J Massobrio Alicia R Fabrizio de Iorio

Accumulation of beef cattle manure on feedlot pen surfaces generates large amounts of dissolved solutes that can be mobilized by water fluxes, affecting surface and groundwater quality. Our objective was to examine the long-term impacts of a beef cattle feeding operation on water fluxes and manure leaching in feedlot pens located on sandy loam soils of the subhumid Sandy Pampa region in Argenti...

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 ...

2003
J. P. Walker N. Ursino R. B. Grayson

Knowledge of temporal and spatial variation in root zone soil moisture content across Australia is vital for a wide range of environmental and socio-economic activities. However, such information is not currently available, due to an inability to monitor with ground-based point measurement techniques at an appropriate spatial resolution, and the uncertainty associated with land surface model pr...

2010
C. Kobayashi O. Kashimura T. Maruyama M. Oyanagi I. C. Lau T. Cudahy D. Carter

In this study, to remove the effects of topography and surface roughness to observed spectrum initially, a method using the normalised reflectance (pseudoreflectance) was employed. Then, we examined the removal of the vegetation effects (such as green vegetation and dry vegetation) and a method to estimate soil pseudo-reflectance spectrum, because the ground surface shows the mixture of soil an...

Journal: :مرتع و آبخیزداری 0
مجید آجورلو استادیار گروه مرتع و آبخیزداری، دانشکدة منابع طبیعی، دانشگاه زابل محبوبه ابراهیمیان دانشجوی دکتری آبخیزداری، دانشکدة جنگل داری، دانشگاه پوترا، مالزی رمضانی عبدالله دانشیار دانشکدة مطالعات محیط زیست، دانشگاه پوترا، مالزی

root morphological and distribution responses of signal grass (brachiaria decumbens) to long-term cattle grazing were examined in a tropical pasture in malaysia. the treatments were no grazing by cattle and grazing at a moderate stocking density (2.7 animal unit/ha) under rotational grazing for 33 years. the method consists of taking soil core using a soil corer to a depth of 30 cm and extracti...

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