Moisture Characteristics of Pennsylvania Soils: II. Soil Factors Affecting Mositure Retention Within a Textural Class—Silt Loam
1968
Petersen, G. W. | Cunningham, R. L. | Matelski, R. P.
The relationships of morphology and other selected soil properties to mositure retained after equilibration at ⅓ and 15 atm (approx. 0.34 and 15.5 kg/cm²) tension was investigated within silt loams. This laboratory study was restricted to an individual textural class in an effort to hold texture relatively constant while scrutinizing the influence of other soil properties upon the soil moisture regime. Available moisture, which is assumed as the difference between moisture retained at ⅓ and 15 atm tension, was generally highest in the A, less in the B, and lowest in the C horizon. This moisture retention however, was more a reflection of coarse fragment content than of such horizon developmental features as clay accumulation, gleying, structural development, or fragipan characteristics. There was no significant difference between the moisture retention of cultivated and noncultivated horizons nor between the moisture supplying abilities of gleyed and nongleyed horizons. Nonfragic horizons retained almost twice as much available moisture as fragic horizons. Moisture retention decreases as coarse fragments increase and therefore moisture retention calculations should be corrected for coarse fragments. Available moisture remained almost constant as organic matter increased within silt loams. Weight percentage contents of kaolinite, illite, vermiculite, montmorillonite, chlorite, and interstratified clays were not significantly correlated with moisture retention. Correlation analyses suggested the 20-5µ silt as the most important <2 mm size separate controlling available moisture and moisture retained at field capacity.
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