نتایج جستجو برای: and mixed with clay or silt soils

تعداد نتایج: 18540106  

Journal: :Journal of environmental quality 2002
Richard McDowell Andrew Sharpley

Phosphorus (P) loss in overland flow varies with spatial distribution of soil P, management, and hydrological pathways. The effect of flow time, flowpath length, and manure position on P loss in overland flow from two central Pennsylvania soils packed in boxes of varying length (0.5, 1.0, 1.5, 2.75, and 4.0 m long x 15 cm wide x 5 cm deep) were examined by collecting flow samples at 5-min inter...

2004
Patrick Durkin

with Kd values. 0.29. Not very detailed.Dickens and Wehtje1986 Kd values: 0.04-0.6 kg/L at 0-20 cmKd values: 0.019-0.036 kg/L at 65-95 cmOnce herb leaches past the top 10 cm of soil, retardation of herbicides would be slight.Contamination of ground water would depend on rate of decomposition. Composition of soils determined, but soil types not classifiedKoskinen et al.<l...

2010
S. Syafruddin

We conducted two laboratory experiments to examine the effects of fertilisation and agitation (aeration) on crude oil degradation in two soils with differential nutrient (nitrogen, phosphorus) availability. Two soils that had been spiked with crude oil two years before were mixed with nitrogen and/or phosphorus at three different levels and subsequently incubated 28 days (Exp. 1). In experiment...

N. Asgari Hafshejani S. Jafari

ABSTRACT-This experiment was carried out to study particle size distribution (PSD) of carbonates in soils and its effect on some calcareous soil properties in Khuzestan Province, Iran. Soil samples (n=72) were collected from different regions. To evaluate the effect of carbonates on water contents at pressure head of -1500kpa and PSD of soil samples, these properties were determined before and ...

2015
Zilin Song Chao Zhang Guobin Liu Dong Qu Sha Xue Rita Grosch

The application of fractal geometry to describe soil structure is an increasingly useful tool for better understanding the performance of soil systems. Only a few studies, however, have focused on the structure of rhizospheric zones, where energy flow and nutrient recycling most frequently occur. We used fractal dimensions to investigate the characteristics of particle-size distribution (PSD) i...

2010
P. K. Robertson

An initial application of CPT results is to evaluate soil type and soil stratigraphy. One of the more common CPT-based methods to estimate soil type is the chart suggested by Robertson et al (1986) based on cone resistance, qc and friction ratio, Rf. Although newer charts have been developed based on normalized parameters, the simple chart based on qc and Rf is still popular because it is easy ...

2013
Mahdi NAJAFI-GHIRI Ali ABTAHI

Najafi-Ghiri M., Abtahi A. (2013): Potassium fixation in soil size fractions of arid soils. Soil & Water Res., 8: 49–55. Amounts of potassium (K) fixed in soil fractions of 10 calcareous soils of southern Iran were measured to evaluate the contributions of different soil size fractions to K fixation. Soil particles were fractionated after dispersion of the soils with an ultrasonic probe. Potass...

Journal: :مرتع و آبخیزداری 0
محسن پادیاب دانشجوی دکتری آبخیزداری دانشکدة منابع طبیعی، دانشگاه تهران سادات فیض نیا استاد دانشکده منابع طبیعی دانشگاه تهران حسن احمدی استاد گروه آبخیزداری، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران اردشیر شفیعی عضو هیئت علمی مرکز تحقیقات کشاورزی و منابع طبیعی استان کهکیلویه و بویراحمد

small precipitation with temporal and spatial variation of rainfall is the main responsible factors on flood occurrence in arid and semi arid regions. floods in their regions usually contain high concentration of sediments which when they are deposited on the surface of lands, they change the properties of soils of the area. in this research, the effect of floodwater spreading on physic-chemica...

Journal: :آب و خاک 0
محمدمهدی چاری بیژن قهرمان کامران داوری علی اصغر خشنود یزدی

introduction: water and soil retention curve is one of the most important properties of porous media to obtain in a laboratory retention curve and time associated with errors. for this reason, researchers have proposed techniques that help them to more easily acquired characteristic curve. one of these methods is the use of fractal geometry. determining the relationship between particle size di...

ژورنال: علوم آب و خاک 2014
رفیعی‌الحسینی, محمد , صالحی, محمدحسن , مصلح, زهره ,

  Many studies have been carried out on pure minerals to study the effect of plant roots on minerals weathering, but information on mineral weathering that normally occurs in different soil fractions is limited. To investigate the effect of German Chamomile (Matricaria chamomilla L.) cultivation on mineral weathering of clay and silt fractions in five different soil series amended or not amende...

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