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Classification and management of earthen aquaculture ponds, with emphasis on the role of the soilBowman, James R. 09 January 1992 (has links)
Soil, water, and climatic classification systems are reviewed as
background for the construction of a classification system for earthen
aquaculture ponds. The physical and chemical properties of important
soil types are also reviewed because of the critical role that the
soil plays in earthen pond systems. A pond classification system is
constructed using key elements from established climate, water, and
soil classification systems, and its use as a management tool is
demonstrated. Additional benefits of pond classification are
discussed.
Functional relationships pertaining to a particular management
practice--the application of lime--are examined for seven classes of
acid soils. Theoretical and empirical models of pH-percent base
saturation relationships are evaluated using data from United States
soils. Selected models are partially validated using an independent
set of data and incorporated into a lime requirement determination
model. A table of lime requirement estimates based on initial soil pH
values is calculated for each soil class.
Partial validation of the classification system is achieved by
ANOVA for the cation exchange capacities of the soils, by fitting the
selected pH-percent base saturation models to data from an independent
source, and by comparison of the estimated lime requirements with
previously published guidelines. Possible reasons for weaknesses in
the classification system, the pH-percent base saturation models, or
the approach to lime requirement determination are explored, and areas
requiring further research are identified. Additional uses and
benefits, and further validation and refinement of the classification
system are discussed. It is concluded that the proposed
classification is a good first approximation that provides a basis for
further work. / Graduation date: 1992
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Biophysical interpretation of spectral indices for semi-arid soil and vegetation types in Niger.van Leeuwen, Willem Jan Dirk,1961- January 1995 (has links)
In situ radiometric field data and data simulated with a radiative transfer model were used to evaluate the performance and biophysical interpretation of spectral indices Concurrently with remotely sensed measurements, temporal biophysical measurements for different vegetation types for two semi-arid regions in Niger were made, including leaf area index (LAI), fraction of absorbed photosynthetically active radiation (fAPAR), percent vegetation cover, and biomass. The spectral dynamics of vegetation and soil were characterized at the leaf and canopy scale by optical measurements under many adverse conditions, including variability in vegetation optical and structural properties, soil reflectance properties, sun and view geometry and atmospheric perturbations. The spectral indices evaluated in this research comprised spectral vegetation indices and spectral mixture model indices, computed from spectral reflectances. The performance of different vegetation indices and their sensitivity to green and non-green vegetation and soils were compared and quantified by utilizing estimates of percent relative error in spectral vegetation indices, and estimates of vegetation equivalent noise expressed in terms of biophysical parameters (LAI, fAPAR). The soil adjusted vegetation index (SAVI) and modified normalized vegetation index (MIND VI) were improvements over the normalized difference vegetation index (NDVI), but were still sensitive to many perturbing variables such as soil and vegetation distribution, soil optical properties, litter and green vegetation optical properties and leaf angle distribution. The spectral mixture model indices were designed to be sensitive to vegetation, soil and non-green vegetation components and were shown to provide useful surface information that can aid in minimizing the noise in spectral vegetation indices, and also in improving their biophysical interpretation. Vegetation and soil brightness imagery were created from remotely sensed reflectance data, by calibrating the spectral mixture model with the data generated with a radiative transfer model. The effect of standing litter on spectral indices was shown to possibly cause both an increase and a decrease in the vegetation index, depending on the coupled spectral and structural properties of litter, green vegetation and soil. In situ measurements confirmed the results obtained from the analysis of data sets generated with a radiative transfer model. The implications of the effect of perturbing variables on spectral indices were also discussed.
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PREDICTION OF ATRAZINE DISTRIBUTION AND MOVEMENT IN SOIL SYSTEMSSwanson, Roger Arliss, 1939- January 1972 (has links)
No description available.
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Clay mineral characterization of young cinder cone soilsAndrew, Allen David, 1945- January 1970 (has links)
No description available.
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A laboratory study of salt movement in artificial soil columnsWarren, John H., Jr. January 1953 (has links)
No description available.
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Influence of the decomposition of organic materials on the physical and chemical properties of some Arizona soilsKleinkauf, Wesley Arthur Lee, 1917- January 1940 (has links)
No description available.
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The effect of field applications of organic matter on the properties of some Arizona soilsSullivan, Michael John, 1918- January 1942 (has links)
No description available.
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The carbon dioxide extraction method of determining available phosphates in alkaline-calcareous soilsPearson, George Allen, 1915- January 1941 (has links)
No description available.
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Chemical methods for evaluating available phosphorus in Arizona soilsJones, James Preston, 1935- January 1959 (has links)
No description available.
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Shear wave data collection in mid America using an automated surface source during seismic cone testingCasey, Thomas J. 12 1900 (has links)
No description available.
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