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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #312965

Title: The Heartland Region P-Index Conservation Innovation Grant: protecting water quality through improved phosphorus management

item NELSON, NATHAN - Kansas State University
item Baffaut, Claire
item VAN LIEW, MIKE - University Of Nebraska
item SENAVIRATNE, ANOMAA - University Of Missouri
item BANDHARI, AMMAR - Kansas State University
item LORY, JOHN - University Of Missouri
item SWEENEY, DAN - Kansas State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/8/2014
Publication Date: 11/13/2014
Citation: Nelson, N., Baffaut, C., Van Liew, M., Senaviratne, A., Bandhari, A., Lory, J., Sweeney, D. 2014. The Heartland Region P-Index Conservation Innovation Grant: protecting water quality through improved phosphorus management [abstract]. Meeting Abstract. Oral presentation.

Interpretive Summary:

Technical Abstract: Reducing phosphorus loss from agricultural land is important for improvement and protection of surface water quality. Agricultural models can be used to determine management impacts on P loss and therefore serve as a guide for recommending best management practices. However, the models must be compared to measured data as a validation prior to their use. The objectives of this study are to i) evaluate the P loss estimates from the Agricultural Policy/Environmental Extender (APEX) model for several soils and management systems common to the Heartland region using various calibration methods; ii) use the validated models to extend the impact of measured data to estimate long-term effects of soils and management on the risk of P loss from agricultural fields; iii) use model results to evaluate and improve P indices in KS, MO, NE and IA. APEX estimated runoff, sediment, and P loss was compared to measured data from 18 watersheds at five sites representing a range of hydrologic conditions and management systems. Although the model performance for flow was acceptable with minimal parameter adjustment (NSE = 0.5), full calibration improved flow estimation (NSE = 0.6). Acceptable estimation of sediment and total phosphorus losses (NSE = 0.7 and 0.6, respectively) was obtained only after full calibration at each site. Models at select sites were used to determine the effects of poultry litter management on P loss. Preliminary results indicate that larger, but less frequent applications of poultry litter do not increase average P losses compared to smaller more frequent applications. However, higher and less frequent poultry litter application rates increase the variability of field-scale P loss. These results can assist and encourage producers to implement best management practices for P loss. Project results also confirm that APEX model results will provide estimates of long-term P loss needed to evaluate and improve state P Indices.