Transfer of moisture through the unsaturated zone in the tropical forest using the neutron probe

Abstract

ABSTRACT:Knowledge of moisture content is crucial in assessing spatial and temporal movement of water through the unsaturated zone. Moisture storage is also important for monitoring the soil water balance and for validation of water balance models. The purpose of this work was to determine and analyse moisture content profiles at point locations in the unsaturated zone of a lateritic soil around Nsimi, south of Cameroon. Neutron probe has been connected to a set of tensiometers in an area of 60 ha. A comparative study between a site covered with vegetation and a site uncovered was conducted to assess the influence of vegetation in the process of moisture transfers. The results showed that the spatial distribution of moisture profiles varied according to the site and the texture of the soil, with in general increasing of moisture from the surface horizon toward the deeper layers. The mean values of moisture varied from θ m = 0,397 cm 3 /cm 3 on barren site, against θ m = 0,429 cm 3 /cm 3 in vegetation. Values of suction were generally strong in surface and at depth, but weak in the intermediate layers.

Kinetic Modelling and Half Life Study of Adsorptive Bioremediation of Soil Artificially Contaminated With Bonny Light Crude Oil

“…Nevertheless, contrary observations on the effects of strong AC amendments on pollutant biodegradation processes have been reported. The addition of AC to contaminated soils was shown to reduce spiked 14 C phenanthrene metabolism to 14 CO 2 in laboratory batch experiments. Karapanagioti et al [2001] showed that slow sorption kinetics limited spiked phenanthrene biodegradation in sediment slurries containing coal particles.…”

“…As a result of this limitation, great deals of literature have reported that bioremediation methods are alternatives and/or supplements to these methods. This is because of their cost effectiveness, environmental friendliness, simplicity in technology and conservation of soil texture and characteristics [Mandri and Lin, 2007; Adams and Guzmán-Osorio, 2008; Fouépé et al, 2009]; however, the method requires longer treatment time [Agarry and Ogunleye, 2012]. Despite the great advantages of bioremediation, this approach is now used in only about 5% of all soil treatments [Vasilyeva et al, 2006].…”

Earthworm-assisted bioremediation of petroleum hydrocarbon contaminated soil from mechanic workshop

“…Due to limitations of the physicochemical technologies, great deals of literature have reported that bioremediation technologies are alternatives and or supplements to these technologies. This is because of their cost effectiveness, environmental friendliness, simplicity in technology and conservation of soil texture and characteristics (Vidali, 2001;Yerushalmi et al, 2003;Adams and Guzman-Osorio, 2008;Fouépé et al, 2009). Bioremediation of petroleum hydrocarbons suffers mass transfer limitations as a result of the high hydrophobicity and low solubility of the contaminants in aqueous media (Li et al, 1995).…”

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“…Soil moisture measurements were carried out at two hours after saturation, every day for 3 days, every 3 days for 30 days, and every week for two weeks. Measurement of soil moisture in the field was done using the Neutron probe and these measurement results were calibrated with the gravimetric soil moisture content (Fouépé et al, 2009).…”

“…Determination of the neutron probe calibration equation needs the secondary data of the volumetric moisture content, soil fresh-weight, soil dry-weight, soil bulk density, soil moisture tension (Fouépé et al, 2009). Volumetric soil moisture content data were obtained by soil sampling at the several depths.…”