In the Senegal valley, it is commonly considered that the Acid Sulfate Soils of the delta are fossil soils overlain by more recent sediments, and that the Vertisols, which abruptly overlie a thick sandy horizon, result from a change in the sedimentation mode of the river. However, we show that both soils belong to the same pedological system extending from the delta to the limit of the last mar...

This study aimed to evaluate the effect of shrub encroachment on soil organic carbon (SOC) content at broad scales and its controls. We conducted a meta-analysis using paired control data of shrub-encroached grassland (SEG) vs. non-SEG collected from 142 studies worldwide. SOC contents (0-50 cm) were altered by shrub encroachment, with changes ranging from -50% to + 300%, with an effect size of...

seismic piezocone device (scptu) together with resonant column and cyclic triaxial test apparatus are employed to measure small strain shear modulus (g0) of carbonate sandy and clayey soils of southern coasts of iran. a large area of southern regions of iran is formed from clay, silt and sand. in this study, maximum shear modulus that is derived from both field (by seismic piezocone) and labora...

Arenosols in the Brazilian Cerrado are increasingly being used for agricultural production, particularly maize. These sandy soils are characterized by low soil organic matter, low available nutrients, and poor water-holding capacity. For this reason, adding biochar as a soil amendment could lead to improved water and nutrient retention. A greenhouse experiment was carried out using twelve bioch...

Heating effects on carbon and mineral nitrogen contents of soils within different land use types were investigated in this study. With this intention we collected soil samples from 3 different land use types which are abandoned agricultural lands (AAL), shrub land (SL) and Oak forest land (OFL) and are in neighborhood with each other. The sampling was made at mid-summer to provide a better corr...

Fluorescein diacetate (FDA) hydrolysis is widely accepted as an accurate and simple method for measuring total microbial activity in a range of environmental samples, including soils. Colourless fluorescein diacetate is hydrolysed by both free and membrane bound enzymes, releasing a coloured end product fluorescein which can be measured by spectrophotometry. The current method for measuring FDA...

BACKGROUND AND AIMS Root soil penetration and path optimization are fundamental for root development in soil. We describe the influence of soil strength on root elongation rate and diameter, response to gravity, and root-structure tortuosity, estimated by average curvature of primary maize roots. METHODS Soils with different densities (1·5, 1·6, 1·7 g cm-3), particle sizes (sandy loam; coarse...

Seismic piezocone device (SCPTu) together with Resonant Column and Cyclic Triaxial test apparatus are employed to measure small strain shear modulus (G0) of carbonate sandy and clayey soils of southern coasts of Iran. A large area of southern regions of Iran is formed from clay, silt and sand. In this study, maximum shear modulus that is derived from both field (by seismic piezocone) and labora...

abstract agriculture is the largest consumer of water resources in iran. one of the best options for increasing the irrigation efficiency and better application of precipitation in arid and semi-arid areas is employing of superabsorbent polymers to soil. polymers can absorb rain and irrigation water, decrease deep percolation and increase water use efficiency. in order to investigate the effect...

Describes field experiments to determine the effects of previous organic waste composts, using different types and application rates, on sunflower yield. Oil, carbohydrates and metal content were evaluated. Experiments were conducted in the Nuclear Research Centre Farm, in sandy, infertile soil. Results show a remarkable increase in dry matter and seed yields, due to previous single compost add...