| dc.description.abstract | The objectives of this research were to classify sediments from wild rice
lakes, and to examine, in detail, one type of sediment that is not suitable for
commercial production of wild rice.
Based on physical and chemical differences, cluster and discriminant analysis
classified sediments from 39 potential and existing wild rice lakes into clay, organic,
flocculent, organic-flocculent, organic-clay, and organic over clay (organic/clay)
types. The major differences among the six sediment types were the percent loss on
ignition, bulk density, phosphorus and cation content, and pH values. Wild rice
production was best in organic, organic over clay, and organic-clay sediments.
Flocculent, clay, and organic-flocculent sediments produced the lowest dry weights
of individual plants.
Organic-flocculent and organic/clay sediments were examined for further
physical and chemical differences, as well as seasonal nutrient trends and wild rice
production. Organic-flocculent and organic/clay sediments were found to have
C:N>10, and similar inorganic biogenic composition, mineral content, pH, and redox
values. Major differences in nutrient values were found to exist between the
sediments. Lower nutrient values (except N) in organic-flocculent sediment appear
to be closely linked to the origin, type, and degree of decomposition of the organic
material within the sediment. A comparison of seasonal nutrient trends between
organic-flocculent and organic/clay sediments showed no nutrient depletion during
the exponential growth of wild rice.
Fertilizer trials and foliar nutrient deficiency symptoms determined which
nutrients were limiting production in organic-flocculent sediments. Phosphorus was found to be the main limiting nutrient; nitrogen deficiency played a secondary role.
Plants grown in unfertilized organic-flocculent sediments displayed the purple leaves
and slower maturation rate characteristic of phosphorus deficiency. | |
