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Granitic bedrock, generally weathered several meters deep, is widespread in upland areas of California. Sound management of these areas requires knowledge of the hydraulic properties of both soils and weathered bedrock. The objectives of this research were to determine the saturated hydraulic conductivity (Ksat) of weathered granitic bedrock and overlying soils and to relate the measured Ksat to the regolith morphology and porosity. The study sites in the foothills of the San Jacinto Mountains represent common regolith conditions in granitic terrain of southern California: a coarse‐loamy Entisol <50 cm thick and a fine‐loamy Alfisol ≈ 100 cm thick, both over weathered granitic rock. The underlying bedrock (Cr horizon) at each site has a low clay content (<6%) and is weathered such that chunks of it can be excavated by chopping with a spade and crushed into grains using bare hands. In situ Ksat, measured using constant‐head permeameters, was highest (29 cm h−1) in the Entisol AC horizon, which also had the greatest macrovoid (>0.1 mm diam.) space (24%), a low clay content (6%), and abundant roots to provide pore continuity. A pedogenic horizon also had the lowest Ksat, with the Alfisol Bt horizon averaging 0.9 cm h−1. This horizon had 9% macrovoid space and 21% clay. The Cr horizons had intermediate Ksat values (1.4–3.7 cm h−1). Low clay contents, joint traces, and macrovoids (7–9%) largely unimpeded by illuvial clay help make weathered granitic bedrock an effective conductor of water under saturated conditions. On a landscape scale, water should percolate readily into regolith on Entisol sites, whereas runoff is more likely on Alfisol sites due to the low Ksat of the Bt horizon.

This study examined the application of a relatively new automated three‐dimensional scanning technology to bulk density determination of intact soil clods and rock fragments. The method uses an inexpensive commercially available three‐dimensional desktop scanner. Measurements obtained by the scanning method were compared with those of the paraffin‐coated clod method determined on the same clods. Results showed excellent agreement between volume and bulk density measurements obtained by the two methods across a wide range of textural classes. Use of the technology has several important advantages over the traditional clod method. The nondestructive nature of the scanning method makes it possible to use the same intact ped or clod for other purposes, such as thin sections for micromorphological analysis. In addition, high‐resolution digital imaging opens up possibilities for new physical measurements of soil morphological features.

Crops tolerant to salt and boron have an advantage when grown in soils, near power plants, that are contaminated by saline cooling tower water or by waste products such as coal fly ash containing high levels of B. In addition, tolerant crops may have higher yields in arid and semi arid regions where salt and B problems coexist. This greenhouse study was conducted in order to compare the response of tepary bean (Phaseolus acutifolius A. Gray) and kidney bean (Phaseolus vulgaris L.) to combinations of high levels of solution B and chloride salts. The plants of both species were grown in 10-L plastic buckets containing silica sand and were irrigated with half-strength Hoagland's No. 1 nutrient solution to which boric acid and a mixture of NaCl and CaCl2·2H2O on a 1:1 equivalent ratio were added. Boron treatments consisted of 5, 20, and 25 mg·L-1 and the target electrical conductivity (EC) levels were 1, 4, 8, 12, and 15 dS·m-1. The maximum growth and yield for tepary bean occurred at 5 mg·L-1 B and 4 dS·m-1. These values of B and salinity were 6.5 and 4 times higher than those threshold values reported for kidney bean. Furthermore, tepary bean produced profitable yield (80% of control) in the 5 mg·L-1 B, 8 dS·m-1 treatment and it even produced beans at B concentration as high as 20 mg·L-1 B, four times higher than that observed for kidney bean.