The objective of this report is to present simulation analyses of heat and water flow during soil freezing. The analyses utilize a modified form of a model presented by Harlan. The model is tested by using experimental data reported by Dirksen and Miller and Jame and Norum. The basic elements of the model are the heat and water flow equations. An implicit finite-difference scheme is used to solve these two equations for the boundary conditions used in the experiments. The agreement between simulated and experimental results is illustrated for temperature, water, and ice contents.

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A resistance network analog is described which incorporates some improved features in flexibility, accuracy, and ease of operation. The network consists of 575 variable resistance units and is mounted on a 6-by 8-foot board. The resistive units are of the plug-in type, and the mesh size is smaller on one-fourth of the board. The use of a control console, automatic digital voltmeter and numerous switches permits rapid measurement of voltages and currents.Improved equations are presented for calculating network resistances adjacent to the drain. These equations utilize a logarithmic expression rather than a linear one as reported by previous investigators. Comparisons are made of drain flow rates in homogeneous medium as evaluated by the network and by analytic solutions of Kirkham. Compared to the analytical solutions, the network data generally deviates < 2% if the logarithmic expression is used to calculate drain resistors; while deviations as high as 30% or more may occur if a linear relationship is utilized.

The drawdown in a pumped unconfined aquifer can be analyzed by computer methods. The computer can give simultaneous solutions for flow in the saturated and unsaturated zone. The surface of seepage can also be included in the analysis.

The mineral uptake by corn (Zea mays L.) was studied in field lysimeters for the following variables: constant water table (WT) depths, intermittent flooding, and two levels each of N and the micronutrients Zn and Cu. The WT depths. of 15 and 30 cm and intermittent flooding during early growth decreased the ear leaf concentrations of N, P, K, Zn, Cu, and B and increased the leaf concentrations of Al, Fe, Mn, and Mo. Applications of N, Zn, and Cu increased the concentrations of N, P, Zn, Cu, B, Mn, and Fe but decreased that of K. Mineral uptake under wet soil conditions was associated with reducing conditions, inhibited soil mineralization and an increase in soil pH.