The relative humidity at the surface of a soil is calculated as a function of time from a realistic, exactly solvable model for unsaturated fluid flow. When the evaporation rate is constant, as in the atmosphere-controlled phase, the surface relative humidity suddenly drops at a particular time, even though the humidity–time function is differentiable. This sudden transition still occurs, but i...

Assessing the behaviour of organic chemicals in soil is a complex task as it is governed by the physical chemical properties of the chemicals, the characteristics of the soil as well as the ambient conditions of the environment. The chemical partitioning space, defined by the air-water partition coefficient (K(AW)) and the soil organic carbon-water partition coefficient (K(OC)), was employed to...

Novel evaporation experiment to determine soil hydraulic properties K. Schneider, O. Ippisch, and K. Roth Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany Interdisciplinary Center for Scientific Computing, University of Heidelberg, Heidelberg, Germany Received: 24 April 2006 – Accepted: 27 April 2006 – Published: 29 June 2006 Correspondence to: K. Schneider (kla...

The Penman-Monteith equation is useful for computing evaporation rates of uniform surfaces, such as dense vegetation or bare soil. This equation becomes less useful for evaluation of evaporation rates at the regional scale, where surfaces are generally characterized by a patchy combination of vegetation and soil. This is particularly true in the arid and semi-arid regions of the world. The appr...

Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Papers published in Hydrology and Earth System Sciences Discussions are under open-access review for the journal Hydrology and Earth System Sciences Abstract Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Abstract The soil-water balance and plant water use are investi...

Sugarcane is a major land use in KwaZulu-Natal and Mpumalanga and competes with other crops, as well as industrial and domestic water users, for water resources. Approximately 420 000 ha is currently under sugarcane in South Africa, of which approximately 21% is irrigated, primarily supplying the northern mills of Malelane, Komati, Pongola, Umfolosi and Felixton. In the northern areas where ann...

Many engineered barriers are expected to function for hundreds of years or longer. Over the course of time, it is likely that some barriers will experience infiltration to the point of breakthrough. This study compares the recovery from breakthrough of two storage-evapotranspiration type engineered barriers. Replicates of test plots comprising thick soil and capillary-biobarrier covers were wet...

oped (Wind, 1968; Becher, 1971; Boels et al., 1978; Schindler, 1980; Tamari et al., 1993; Wendroth et al., Soil hydraulic properties are important parameters affecting water 1993; Halbertsma and Veerman, 1994). flow in variably saturated soils. We estimated the hydraulic properties from a laboratory evaporation experiment using both a parameter An important modification was suggested by Wind es...

The objective of this work was to explain an apparent contradiction in the literature related to the relationship between mean and variance (or standard deviation) of soil moisture fields. Some studies found an increase in soil moisture variance with decreasing mean soil moisture, while others showed a decrease. The evidence of maximum variance in the mid-range of mean soil moisture was also re...

Np, for NPP Nec, Net ecosystem carbon exchange, as measured by micrometeorologists NB, Net biome productivity Gp, Gross primary productivity Jpmax, maximum flux density of canopy photosynthesis Reco, ecosystem respiration Rplant, plant respiration Rauto, soil autotrophic respiration Rhetero, soil heterotrophic respiration Rsoil, total soil respiration Ea,actual evaporation Ep, potential evapora...