Submitted to: Ecological Society of America Bulletin
Publication Type: Abstract Only
Publication Acceptance Date: 8/12/1999
Publication Date: N/A
Citation: Marquez, C.O., Cambardella, C.A., Isenhart, T.M., Schultz, R.C. 1999. Temporal dynamics of aggregates and organic matter in stream riparian zone soils [abstract]. Ecological Society of America Bulletin. Available: www.esa.org/publications
Technical Abstract: Riparian buffer zones can potentially increase soil C sequestration and enhance surface water quality in the intensively-row-cropped upper Midwest. The purpose of this study was to quantify seasonal changes for soil organic C, biologically-active soil C, and aggregate size distributions in a 7-yr old multi-species riparian buffer strip, a natural mixed hardwood forest riparian zone, a cool season grass riparian zone, and streamside cropped fields in central Iowa. We collected soil samples to a depth of 15 cm once a month from April-November in 1997 and in early spring, mid-summer, and early fall in 1998. Total soil organic matter C, light and heavy particulate organic matter C, and aggregate size distributions and stability were quantified. Macroaggregate size distributions changed across the growing season and varied among the vegetation types. For example, cool season grass macroaggregate distributions followed a bimodal pattern, with maximum macroaggregation occurring in early spring and early fall. Peaks in macroaggregate stability also appeared to coincide in time with expected periods of rapid plant growth. The data suggest that biologically-active organic matter C responds to time of sampling, and the temporal pattern appears to vary among vegetation types. Further analysis of the data will provide a more detailed description of these temporal patterns and will permit the development of relationships between temporal changes in macroaggregation, aggregate stability, and biologically-active soil organic C.