Date of Award

1992

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Plant, Enviromental and Soil Sciences

First Advisor

Wayne H. Hudnall

Abstract

This study had the purposes of investigating the aquic conditions of two selected Natraqualfs to define the relationship between wetness and morphological properties and prediction of major soil processes. The proposed criteria for aquic conditions as defined by the International Committee on Aquic Conditions (ICOMAQ) were identified by: (i) presence of redoximorphic features, and (ii) measurement of saturation and reduction. They were used to locally verify morphological inferences used to predict the aquic conditions. Morphological properties and laboratory analysis were used to predict the periodicity and duration of saturation and reduction. Soil and ground water analyses were used to understand the fate of electroactive species to predict reduction. Physical, chemical and mineralogical data were used to predict major soil environmental processes relationship with aquic conditions. Results indicate that: (i) both soils supported aquic conditions with episaturation; (ii) redoximorphic features found in both soils did not define uniquely soil episaturation or endosaturation; (iii) episaturation produces long periods of stagnation when precipitation exceeds evapotranspiration, otherwise episaturation occurs far very short periods of less than 2 weeks; (iv) the redox capacity factors OXC and AC predicted anaerobic conditions that correlated well with field Eh measurements; (v) the strong horizon differentiation between E and B horizons is the product of dispersion and degradation of clay minerals. Dispersion and degradation occur by interaction of seasonally wet conditions and the presence of Na in the soil system.

Pages

197

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