Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/9/2000
Publication Date: 11/9/2000
Citation: MALLARINO, A.P., BAKER, J.L., DOWNING, J.A., FENTON, T.E., MILLER, G.A., SAWYER, J.E., STEWART, B.M., KOVAR, J.L. DEVELOPMENT OF A PHOSPHORUS ASSESSMENT TOOL FOR IOWA. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2000. CD-ROM. MADISON, WI.
Technical Abstract: Excessive phosphorus (P) loss from soil impairs water quality in surface water bodies. A P assessment tool or index has been proposed to identify fields with potential risk of P loss. The index integrates P source and transport field characteristics into a decision making process that may lead to changes in current management and soil conservation practices. The index recognizes that establishing one soil-test threshold is not appropriate with the varying conditions across the state. The Iowa index adapts characteristic elements common to most indices being developed in the U.S. Source and transport characteristics are considered in a multiplicative manner in three factors to yield an overall relative risk index. An erosional factor considers sheet and rill erosion, sediment delivery rates, P enrichment, soil-test P, total soil P, and buffers. A runoff factor considers water runoff (based on a modification of the runoff curve number), soil-test P, rate, time, and method of P application. An internal drainage factor considers the presence of tiles, an index of water flow through the soil profile, soil-test P, and rates of P application. Use of this tool will provide alternative management criteria for reducing P losses from soil.