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RELATIONSHIP OF MORPHOLOGICAL INDICATORS OF SOIL WETNESS AND FREQUENCY AND DURATION OF SATURATION
Abstract
In classifying soils, moisture regimes are essential in separating Orders, Suborders, and Great Groups. Since saturation status influences reduction, oxidization, mineral solubility and leaching, it controls to a great extent the genesis of the soil. Saturation status has never been measured directly on soils of eastern Nebraska, instead soil color and contrasting mottles have been used as indicators of moisture regimes. To examine the relationship of morphology of mottles to moisture regimes, ten sites were selected where soils were different in their colors/distribution and depth of mottles. Water content of the soil from 0-1.80 m depth in 0-0.30 m increments was monitored weekly by neutron scattering for three years. Water content data were then converted to saturation status by determining duration and frequency of saturation. Results indicate that the ten sites are naturally grouped in three regimes based on saturation status. The first regime remained unsaturated at all depths, the second regime was saturated for about half the time of the wettest one. Among these groups, more variation was due to saturation and the properties effecting it than neither the chroma nor the color of mottles. Chroma 2 mottles existed regardless of whether the soil was saturated or not. In addition, the same color mottles were observed at depths where soils were saturated for different durations. However, distribution of mottles in the interior and the exterior of peds were associated with duration of saturation. The discriminant function that separated the regimes classified 85% of unknown soils correctly. The study was extended to try digitization techniques to quantify and characterize the color of these soils. Color of the soils were separated into three primary colors (red, green and blue). The results indicate that soils with wettest regime have less red color than medium and dry, respectively. In addition, primary colors for all sites were clustered into their original regimes.
Subject Area
Agronomy
Recommended Citation
AL-ABED, SOUHAIL RADHI ALI, "RELATIONSHIP OF MORPHOLOGICAL INDICATORS OF SOIL WETNESS AND FREQUENCY AND DURATION OF SATURATION" (1986). ETD collection for University of Nebraska-Lincoln. AAI8715843.
https://digitalcommons.unl.edu/dissertations/AAI8715843