Theme Overview: Agriculture and Water Quality in the Cornbelt: Overview of Issues and Approaches

Resource /Energy Economics and Policy, Q25,

Riparian forests with and without grass filters as buffers of concentrated flow from crop fields

Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.A vegetation inventory within naturally occurring forested riparian buffers (natural forest buffers) and a survey comparing buffering of concentrated flow paths (CFPs) by natural forest buffers with and without planted grass filters was conducted along first and second order streams in three northeast Missouri watersheds. Seven natural forest buffers without grass filters were inventoried and found to be composed of dense stands of mixed tree species with a forest floor cover comprised largely of unrooted woody plant debris, which does not adequately buffer concentrated runoff. Seventy-four CFPs were found in row crop fields along 10 natural forest buffers with or without grass filters established using USDA conservation practice standards. Natural forest buffers without grass filters dispersed 80 [percent] of CFPs before they reached the stream, while those with grass filters dispersed 100 [percent]. We estimated 473 metric tons of sediment moved to the buffers/filters via CFPs since last tillage. Nine of the 74 CFPs passed completely through natural forest buffers without grass filters, and accounted for 97 metric tons of the total estimated 473 metric tons. The average width of breached forest buffers without grass filters was 12.8 m, while the width of those not breached was 17.9 m. Average width of cool-season grass filters (CSGF) adjacent to forest buffers was 17.6 m, while average width of warm season grass filters (WSGF) was 22.1 m. These data, along with previous research, suggest that adding a grass filter along narrow natural forest buffers would improve water quality by reducing sediment loss to streams.K.W. Knight (1), R.C. Schultz (2), C.M. Mabry (2), T.M. Isenhart (2), and L. Long (2) ; 1. The Nature Conservancy, Skagit River Office, 410 N. 4th St., Mt. Vernon, WA 98273. 2. Dept. of Natural Resource Ecology and Management, Iowa State University, 339 Science II, Ames, Iowa 50011-3221.Includes bibliographical references

A Tale of Three Watersheds: Nonpoint Source Pollution and Conservation Practices across Iowa

Resource /Energy Economics and Policy, Q25,

Identification of a Carboxyl group at the Active Site of Barley MaIt Phosphatase

The dependence of the maximal velocity, Vm with pH for barley malt phosphatase has been studied from pH 4.0 to 5.4. The data show that an ionizable group in the enzyme-substrate complex with a pK2 of 4-4.6 is important for enzymic activity. These results suggest strongly the involvement of a carboxyl group of a glutamic or aspartic acid residue at the active site of this enzyme

Nitrous oxide emissions from riparian forest buffers, warm-season and cool-season grass filters, and crop fields

International audience(Civ. 1re, 18 sept. 2008, pourvoi n° 07-17.270, arrêt n° 849 F-P+B+I, D. 2008. AJ. 2343, obs. V. Avena-Robardet