Peter J. Shouse

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tially variable soil properties that affect crop yield to better optimize crop productivity and to maintain the Crop yield inconsistently correlates with apparent soil electrical sustainability of agriculture. conductivity (ECa) because of the influence of soil properties (e.g., Site-specific crop management is the management of salinity, water content,(More)
Because of field-scale heterogeneity in soil hydraulic and solute transport properties, relatively large-scale experiments are now increasingly believed to be critical to better understand and predict the movement of water and dissolved solutes under field conditions. In this study, five field experiments were conducted on short blocked-end furrows to(More)
Many regions of southern California's coastal sage scrub (CSS) are rapidly declining as exotic annual plants replace native shrubs. During this conversion, the subsurface hydrology of the semiarid hillslopes that support CSS may be altered. This could chronically suppress the ability of native shrubland to revegetate the landscape since ecosystem processes(More)
One of the most common vehicles by which Escherichia coli O157:H7 may be introduced into crops is contaminated irrigation water. Water contamination is becoming more common in rural areas of the United States as a result of large animal operations, and up to 40% of tested drinking-water wells are contaminated with E. coli. In this study, 2 contrasting soil(More)
tiveness of TDR. However, the emergence of low-cost, high-frequency oscillators has led to an increased interThe capacitance (CAP) method and time domain reflectometry est in CAP techniques (e.g., Dean et al., 1987; Evett (TDR) are two popular electromagnetic techniques used to estimate soil water content. However, the frequency dependence of the real and(More)
The Arya-Paris model is an indirect method to estimate the soil water characteristic from particle-size data. The scaling parameter, a, in the original model was assumed constant for all soil textures. In this study, a is defined as a, = (logJV//log«,-), where n, is the number of spherical particles in the ith particle-size fraction (determined by the(More)
Methods to predict soil hydraulic properties frequently require information on the particle size distribution (PSD). The objectives of this study were to investigate various protocols for rapidly measuring PSD using the laser diffraction technique, compare the obtained PSD with those determined using the traditional hydrometer-and-sieves method (HSM), and(More)
The objectives of this study were to: (i) examine the efficacy of two sampling techniques for characterizing solute transport under steady-state water flow, (ii) study the variation in transport model parameters with increasing depth of solute leaching, and (iii) perform model discrimination to examine the transport process operative within a field plot.(More)
Forty years after conversion from chaparral to perennial veldt grass in the San Dimas Experimental Forest, we compared land surface and soil properties between areas of the two vegetation types. Our objective was to evaluate the impact of this vegetation conversion on the soil physical properties likely to impact zero-order watershed hydrology. In three(More)
Soil and water resources can be severely degraded by salinity when total salt input exceeds output in irrigated agriculture. This study was conducted to examine partitioning of Ca2+, Na+, and Cl- between soil and soybean [Glycine max (L.) Merr.] plants under different irrigation regimes with both field and modeling assessments. In drip and sprinkler(More)