Tillage, cropping, harvest, and nutrient management systems impacts on phosphorus loss with surface runoff: A research update
Date
Authors
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Authors
Research Projects
Organizational Units
Journal Issue
Is Version Of
Versions
Series
The Iowa State University Integrated Crop Management Conference is Iowa's premier crop production education event. No other program in Iowa brings together the diverse range of topics, slate of expert presenters and results of the latest University research.
The ICM Conference offers workshops focusing on the latest in crop production technology. Experts from Iowa and surrounding states will provide research updates and results in soil fertility, soil and water management, crop production and pest management.
Department
Abstract
Eroded soil and phosphorus (P) impair several Iowa lakes and streams, and exported P contributes to hypoxia in the Gulf of Mexico. Most of the sediment and P originate from agricultural fields and stream banks. Phosphorus is lost from fields mainly by surface and subsurface transport processes, although delivery through water erosion and surface runoff accounts for the vast majority of the P reaching surface water bodies. The P lost with runoff can be classified into particulate P, dissolved reactive P (DRP), and bioavailable P (BAP). Particulate P includes forms in or attached to soil mineral and organic particles (sediment-bound P), and has been reported to account for 60 to 90% of P transported with surface runoff. Dissolved reactive P includes mainly orthophosphate P that was desorbed from soil, leached from plant residues, and dissolved from recently applied fertilizer or manure. Bioavailable P is an estimate of P available to algae and aquatic plants over a short period of time, and includes dissolved P and P weakly retained by soil constituents. A significant portion of the sediment-bound P becomes available to algae over a longer period of time.