Estimating water infiltration and retention characteristics using a computer program in R

Mixed-effects modelling of time series NDVI-rainfall relationship for detecting human-induced loss of vegetation cover in drylands

“…Some authors have used it to improve the accuracy of mathematical models (Pinheiro and Bates, 2000;Faraway, 2006). Others have used it in environmental modelling to account for important correlates which can give additional insights on the management factors affecting the environmental processes (Omuto et al, 2006;Omuto and Gumbe, 2009). These applications encourage the need to test the potential of mixed-effects in accounting for the differences between and within vegetation types when modelling NDVI-rainfall relationships.…”

Effect of fast pyrolysis biochar on physical and chemical properties of a sandy soil

“… Ѳr = Residual water content  Ѳs = Saturation water content  α ~ 1/P Pressure at which slope is the steepest  'n' is related to slope at P greater slope, greater 'n' (Parameter explanation was extracted from van Genuchten (1980)) The analysis of the water retention curves was carried out using a non-linear mixed model (HydroMe R package (Omuto and Gumbe, 2009)). Available water-holding capacity was analyzed using a linear model (Proc Mixed, SAS 9.2, SAS Institute Inc., Cary, NC, USA), where the terms in the model were incubation day (1, 15, 29 and 91days), biochar (control, DRR_3, DBR_6, UTM_3 and UTM_6), and the interaction between incubation day and biochar.…”

Review of Soil Water Retention Characteristic (SWRC) Models between Saturation and Oven Dryness

“…( ) and residual moisture contents 2 r θ in the textural pore-space; 1 α represents the inverse of air-entry potential in the structural pore-space; 2 α represents the inverse of air-entry potential in the soil textural pore-space; r θ is the sum of residual moisture contents in the structural pore-space ( ) …”

“…Adsorption is responsible for moisture held on the surface of soil particles while capillarity holds water in the pores between the soil particles or between aggregates of the particles [1]. The relationship between combined effect of these forces (also often expressed in the form of potential head) and soil water content forms a basic property of soil referred to as the Soil Water Retention Characteristics (SWRC) [2]. Typically, soils exhibit large variations in space and occasionally in time as well.…”