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A 3‐year experiment was conducted to monitor and subsequently predict field water contents using the water transport model. Saturated hydraulic conductivities and soil water characteristic curve results were measured and averaged for each soil layer. The Millington‐Quirk (MQ) method was used to calculate average model parameters. Direct use of the MQ‐derived conductivity and diffusivity functions did not give an exact fit to the observed field results. However, when reasonable adjustments were made to the K(θ) and D(θ) functions the prediction was improved considerably. The methodology for “averaging” and utilizing field data to derive model parameters, and subsequent adjustment or optimization of the model parameters all require more research if we hope to use the unsaturated flow equation for field water content prediction.

Nitrate nitrogen and chloride concentrations were monitored in a 3‐year field study in order to examine factors affecting their variability. Fertilized and control plots, established each year, were sampled at least eight times throughout the year by removing about six‐replicate soil cores for individual analyses each sampling time. It was found that non‐uniform fertilization application accounted for 38 to 100% of the sampling variability immediately after fertilization. In fall and spring, differential rates of leaching of NO3‐N and Cl appeared to contribute significantly to variability increasing C.V.'s from about 40% to over 100%. Field and model results showed that differential leaching patterns could be attributed to two main factors: (i) variability of physical properties that determine water storage and transport, and (ii) point differences in redistribution of incoming rain (runoff) due to differences in surface microrelief.

A noncontacting soil resistivity probe, based on electromagnetic induction, was used to measure soil salinity. Good correlations were obtained between the apparent bulk soil conductivity measured by the instrument and the electrical conductivity of saturated paste extracts or the bulk electrical conductivity measured by the Wenner four‐probe method. The electromagnetic induction technique provided less detailed information on salinity changes with depth than the other methods, but was faster and can provide a continuous record of salinity changes along a transect.