Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 11/9/2000
Publication Date: 11/9/2000
Citation: Marquez, C.O., Cambardella, C.A., Isenhart, T.M., Schultz, R.C. 2000. Seasonal trends in soil organic matter and aggregates in multi-species riparian buffers, forests, and crop fields. American Society of Agronomy Meetings. P.384.
Technical Abstract: A study was conducted to quantify season changes in soil organic matter associated with aggregates in a 76-yr-old multispecies riparian buffer (MRB), natural mixed hardwood riparian zones, cool season grass riparian zones, and streamside cropped fields in central Iowa. Surface soil samples were collected in 1997 and 1998. Four aggregate size classes were analyzed for organic matter. Size distribution of aggregates changed throughout the growing season and varied among vegetation types. Carbon associated with macroaggregates (greater than 250 um) followed a bimodal, pattern, reaching a maximum in June (29.5 mgC g-1) and early fall (34.8 mgC g-1). Hardwood forest and switchgrass (MRB) peaked in July (25.1 and 17.9 mgC g-1). Cropped field soil peaked in June-July (12.8 mgC g-1) and decreased in August. These data suggest that seasonal trends in the amount of C associated with macroaggregates responds to temporal changes among vegetation types, especially with very fine root dynamics.