نتایج جستجو برای: topsoil
تعداد نتایج: 1920 فیلتر نتایج به سال:
BACKGROUND Subsurface transport via tile drains can significantly contribute to pesticide contamination of surface waters. The spatial variation in subsurface leaching of normally applied herbicides was examined together with phosphorus losses in 24 experimental plots with water sampled flow-proportionally. The study site was a flat, tile-drained area with 60% marine clay in the topsoil in sout...
Boreal lands have long been considered unsuitable for agriculture. Climate change projections support a shift towards increased agricultural production in boreal ecosystems via land use conversion. Depending on the conversion protocol, new plough layer may variably reflect properties of different soil depths. This study assessed how adding mineral or organic fertilizer sources to distinct layer...
Shallow basal root growth angle (BRGA) increases phosphorus acquisition efficiency by enhancing topsoil foraging because in most soils, phosphorus is concentrated in the topsoil. Root hair length and density (RHL/D) increase phosphorus acquisition by expanding the soil volume subject to phosphorus depletion through diffusion. We hypothesized that shallow BRGA and large RHL/D are synergetic for ...
Concentrations of Cd, Cr, Ni, Pb, and Zn in the top-(0-10 cm) and sub-surface (10-20 cm) soils of the Talcahuano urban area were measured. The main soil properties (organic matter, CaCO3, pH, particle sizes) were determined for a network of representative sampling sites. The mean Cr, Ni, Pb, and Zn contents in the urban topsoil samples from Talcahuano (37.8, 22.6, 35.2, 333 mg kg(-1), respectiv...
Soil contaminant levels and early tree growth data are helpful for assessing phytoremediation systems. Populus (DN17, DN182, DN34, NM2, and NM6) and Salix (94003, 94012, S287, S566, and SX61) genotypes were irrigated with landfill leachate or municipal water and tested for differences in (1) element concentrations (P, K, Ca, Mg, S, Zn, B, Mn, Fe, Cu, Al, and Na) of a topsoil layer and a layer o...
Tianjin urban/industrial complex is highly polluted by some persistent organic pollutants. In this study, the levels of 16 priority polycyclic aromatic hydrocarbons (PAHs) were tested in sediment, water, and suspended particulate matter (SPM) samples in 10 rivers in Tianjin. The total concentration of 16 PAHs varied from 0.787 to 1943 microg/g dry weight in sediment, from 45.81 to 1272 ng/L in ...
The recent widespread increase in iron chlorosis on acid, sandy soils in Florida has led to studies of the underlying causes. The leaves on affected trees are deficient in iron (10). Field observations show that tree condition can be substantially improved by liming. Additions of iron sulphate to the soil has not improved tree condition noticeably. Recently foliage condition improved when small...
The establishment of a vegetative cover to enhance evapotranspiration and control runoff and drainage was examined as a method for stabilizing a landfill containing coal combustion waste. Suitable plant species and pretreatment techniques in the form of amendments, tilling, and chemical stabilization were evaluated. A randomized plot design consisting of three subsurface treatments (blocks) and...
From site-specific crop and soil information collected from a Missouri claypan soil field for over a decade (1993 to 2003), we implemented a precision agriculture system in 2004 with a goal of using site-specific management practices to improve farming profitability and conserve soil and water resources. The objectives of this study were to: 1) show how precision crop and soil information was u...
Metals are ubiquitous within the earth crust. However, the exceptional high-level concentration of heavy metals in the soil due to natural or anthropogenic activities and the chemical forms in which they exist determine the level of risk they portend to the environment. This work was aimed at determining the background level of the presence of seven priority toxic metals (Cr, Ni, Pb, As, Cd, Cu...
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