The vertical migration of M. incognita juveniles introduced at 20 cm from the roots was studied in five natural soils, 100% silica sand, 95% silica sand with 5% clay, 90% silica sand with 10% clay, and 95% silica sand with 5% clay as a concentrated layer. In natural soils the percentage of juveniles capable of migrating 20 cm and penetrating the roots decreased when the percentage of clay and s...

The study of the strength reconstituted and stabilised soft soils is very important in geotechnical engineering. soil particles, such as clay, sand, silt play roles determining behaviour soils. clay sand particles are unique; however, lie a transitional form between clay. Therefore, this paper seeks to investigate (a) effect contents on soils; (b) content cement-stabilised (c) microstructure sp...

Incubation experiment was conducted on four soil types in Nigeria using cattle dung (CD) at the rate of 2.5g/kg soil ( 5 t ha), Urea fertilizer at the rate of 0.1g/kg soil ( 200 kg ha ) and cattle dung (2.5g/kg soil) combined with Urea 0.05g/kg soil (100 kg ha) as treatments. The objective of the experiment was to compare the rate of OC, NH4 – N, NO3 – N and available P release on soils selecte...

sons, clay and organic matter differences between soils should be incorporated into any kind of predictive model. Measuring the cation exchange capacity (CEC) for all horizons of Several researchers have attempted to predict CEC every map unit component in a survey area is very time consuming from clay and organic C contents alone, using multiple and costly. The objective of this study was to d...

Johansson. T. 1995. Site index curves for Norway spruce plantations on farmland with different soil types. Studici Forestulia S~lecicu 198. 19 pp. ISSN 0039-3150, ISBN 91-576-5089-6. Growth data were collected from 157 Norway spruce (Picea abies (L.) Karst.) stands planted on farmland in Sweden. The stands ranged in latitude from 55'N to 66'N. The mean age of the stands was 41 years (range, 25-...

The engineering behavior of nonplastic silts is more difficult to characterize than is the behavior of clay or sand. Especially, behavior of silty soils is important in view of the seismicity of several regions of alluvial deposits in the world, such as the United States, China, and Turkey. In several hazards substantial ground deformation, reduced bearing capacity, and liquefaction of silty so...

In order to evaluate the effects of parent material on clay mineralogy in northface of the Elborz mountain area that is covered with deciduous trees, five mountain physiographical units with dolomite, sandstone, marl, limestone and conglomera parent material were selected and in each physiographical unit some soil profiles were studied. Soil samples were taken from different horizons and leyers...

Palaeosols in the Granada Basin (SE Spain) have been studied in two different situations: surface soils on geomorphically stable surfaces since the Early Pleistocene with younger pedogenic overprinting and buried soils on unstable surfaces from the Middle–Late Pleistocene on which successive erosional–depositional episodes have alternated with pedogenic episodes. For each soil clay and iron acc...

Two soil profile sequences on paragneiss debris in the Val di Rabbi (Northern Italy) along an altitude gradient ranging from 1200 to 2400 m a.s.l. were studied to evaluate the effect of aspect on the weathering of clay minerals. All the soils had a coarse structure, a sandy texture and a low pH. Greater weathering intensities of clay-sized phyllosilicates (greater content of smectites) were obs...

Cement stabilization is one of the commonly used techniques to improve the strength of soft ground/clays, generally found along coastal and low land areas. The strength development in cement stabilization technique depends on the soil properties, cement content, curing period and environmental conditions. For optimal and effective utilization of cement, there is a need to develop a mathematical...