In this study we develop a first-order, nonstationary stochastic model for steady state, unsaturated flow in randomly heterogeneous media. The model is applicable to the entire domain of a bounded vadose zone, unlike most of the existing stochastic models. Because of its nonstationarity, we solve it by the numerical technique of finite differences, which renders the flexibility in handling diff...

Soybean (Glycine max) producers in Ohio rarely use soybean cyst nematode (Heterodera glycines, SCN)-resistant cultivars because of concerns over limited yield potential and lack of resistance to Phytophthora sojae. A two-year study was initiated to determine grain yield and nematode population increase on soybean cyst nematode-resistant cultivars in maturity groups II and III in production fiel...

This study evaluated the effectiveness of soils with different textures and thickness to treat BOD, N and P eluted from household septic effluent. The assessments were accomplished by leaching undisturbed soil monoliths of 30, 45 and 60 cm thickness and 25 cm in diameter, representing the four different textural groups and hydraulic loadings recommended by the Kentucky Health Department, with d...

Estimation of soil hydraulic and solute transport parameters is important to provide input parameters for numerical models simulating transient water ̄ow and solute transport in the vadose zone. The Levenberg±Marquardt optimization algorithm in combination with the HYDRUS-1D numerical code was used to inversely estimate unsaturated soil-hydraulic and solute transport parameters from transient m...

This study compared the granulometric properties, mineralogical composition and concentrations of major and trace element oxides of commonly ingested soils (geophagic soil) collected from different countries with a view of understanding how varied they may be in these properties and to understand the possible health implications of ingesting them. Soil samples were collected from three differen...