Eutrophication of Microponds
1975
Batchelder, A. R.
Three soils having different chemical and physical properties were flooded with deionized water and used as bottom soils for greenhouse microponds. The submerged soils supplied sufficient nutrients to the overlying waters to sustain algal growth for 489 days in two successive floodings of 219 and 270 days each. Differences in electrical conductivity, pH, and nutrient concentration were observed among the three soils and a control nutrient solution. During the first flooding, indigenous algae prevailed in the soil systems, but during the second flooding the dominant algal genera were less diversified. In a companion study, in which perennial ryegrass (Lolium perenne L.) was grown in the same three soils, the grass yields per kilogram of soil could not be related to the ash-free biomass yields per kilogram of soil in the microponds. Algal growth could not be predicted from soil characteristics or solution composition, or the productivity of cropped soils, but the study showed that submerged soils can be a sole source of algal nutrients.
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