نتایج جستجو برای: and mixed with clay or silt soils
تعداد نتایج: 18540106 فیلتر نتایج به سال:
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...
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...
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...
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 ...
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...
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 ...
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...
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...
estimating soil water retention curve using the particle size distribution based on fractal approach
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...
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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