Phosphorus stratification and edge of-field phosphorus losses
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This document summarizes research on phosphorus (P) stratification and edge-of-field P losses in the Western Lake Erie Basin. The research found that subsurface drainage accounted for most annual P loss, while surface runoff was a concern during high rainfall events. Less than half of field sites were meeting P loss targets. Soil test P levels influenced dissolved reactive P (DRP) in both surface runoff and tile drainage, but the influence varied based on flow amounts. P stratification did not predict average annual DRP losses. Greater stratification occurred on fields with surface nutrient application. Management practices that reduce both surface and subsurface P losses are needed.
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Phosphorus stratification and edge of-field phosphorus losses
- 1. P stratification and edge-of-field P losses in the Western Lake Erie Basin SOIL DRAINAGE RESEARCH UNIT
- 2. PHOTOGRAPH BY PETER ESSICK, NATIONAL GEOGRAPHIC
- 3. PHOTOGRAPH BY HARAZ N. GHANBARI, ASSOCIATED PRESS http://www.toledoblade.com/local/2014/08/02/City-of-Toledo-issues- do-no-drink-water-advisery.html PHOTOGRAPH BY JOSHUA LOTT, REUTERS
- 4. Edge-of-Field Research 20 Paired Field Sites Surface Runoff Subsurface Drainage SOIL DRAINAGE RESEARCH UNIT
- 5. Columbus Cleveland Toledo % of county with tile drainage 0-5 5-15 15-30 30-50 50-80 Lake Erie Major city USDA-ARS edge-of-field site Cincinnati Dayton Edge-of-field locations in Ohio Williams et al. 2016. J. Soil Water Conserv. 71:9-12 SOIL DRAINAGE RESEARCH UNIT
- 6. DRP Concentration: Surface > Subsurface on(mgL-1 ) 1 DRPConcentration(mgL-1 ) 0.001 0.01 0.1 1 10 A B TPConcentration(mgL-1 ) 0.01 0.1 1 DRPConcent 0.001 0.01 0.1 March to July Annual B 1.0 2.0 2.5 1.5 3.0 Subsurface Surface Target LoadDRPLoad(kgha-1 ) A Target Conc. 0.05 0.05 0.09 0.21 0.08 0.27 SOIL DRAINAGE RESEARCH UNIT
- 7. 0.5 1.0 2.0 2.5 3.5 4.0 0.0 1.5 3.0 0.5 1.0 0.0 March to July Annual DRTPLoad(kgha-1 ) B DRP Load: Surface < Subsurface 3.5 4.0 3.0 0.5 1.0 2.0 2.5 0.0 1.5 3.0 Subsurface Surface Target Load DRPLoad(kgha-1 )ha-1 ) A B 0.11 0.29 0.13 0.03 0.22 0.06 SOIL DRAINAGE RESEARCH UNIT
- 8. • Subsurface drainage discharge = majority of annual EOF P loss • Surface runoff = concern with high intensity/large rainfall events • Less than half of field sites are currently meeting targets • Surface and subsurface load reduction needed to meet targets and reduce extent of algal blooms in Lake Erie Key points SOIL DRAINAGE RESEARCH UNIT
- 9. Soil Test P vs Environmental Risk King et al., 2018 Duncan et al., 2017 SOIL DRAINAGE RESEARCH UNIT
- 10. Soil Test P vs Environmental Risk King et al., 2018 Soil Test P above agronomic rates poses an environmental risk Duncan et al., 2017 SOIL DRAINAGE RESEARCH UNIT
- 11. Soil Test P vs Environmental Risk King et al., 2018 Soil Test P above agronomic rates poses an environmental risk BUT Soil Test P does not equal environmental risk Duncan et al., 2017 SOIL DRAINAGE RESEARCH UNIT
- 12. Soil Test P vs Environmental Risk King et al., 2018 Soil Test P above agronomic rates poses an environmental risk BUT Soil Test P does not equal environmental risk Duncan et al., 2017 SOIL DRAINAGE RESEARCH UNIT
- 13. Objective Does stratification influence DRP loss? Soil test P and DRP SOIL DRAINAGE RESEARCH UNIT
- 14. #offields 0-1 1-3 3+ P Stratification [M3P] 0-5 cm [M3P] 5-20 cm SOIL DRAINAGE RESEARCH UNIT
- 15. P Stratification and fertilizer recs SOIL DRAINAGE RESEARCH UNIT
- 16. Calculated 50th 75th and 95th percentiles of Qmm for all precipitation events at each outlet for all sites (organized by surface runoff and tile drainage) Selected the corresponding DRP EMC values for each calculated percentile Stats on log transformed data: ANCOVA & linear regressions. Removed STP values < 150 ppm Regressions: STP vs DRP EMC for 0-5 cm and 5-20 cm STP concentrations for each water source (surface and tile) by percentile P Stratification and event data analysis Paired the DRP data with 0-5 cm and 5-20 cm weighted soil test phosphorus conc. SOIL DRAINAGE RESEARCH UNIT
- 17. STP and event DRP for surface and tile As Q in surface r/o relationship between DRP and STP As Q in tile drainage, relationship between DRP and STP Size of the event influences DRP loss more than the STP Each flow path transports DRP differently SOIL DRAINAGE RESEARCH UNIT
- 18. P Stratification and DRP concentrations (surface runoff) SOIL DRAINAGE RESEARCH UNIT
- 19. P Stratification and management SOIL DRAINAGE RESEARCH UNIT
- 20. Does stratification influence DRP loss? Key points SOIL DRAINAGE RESEARCH UNIT • STP does influence surface r/o EMC, but there is no influence of depth (0-5 vs 5-20 cm) or event size • STP does influence tile drainage, depth was only significant in 75th percentile flows, STP explained 21- 48% of variation in DRP EMC • influence of STP on DRP did not vary with tile event size • P stratification did not predict avg. annual DRP EMC • Greater stratification for fields with surface applied nutrients • No significant relationships between tillage practice and stratification
- 21. Acknowledgements Edge-of-Field Team Kevin King, PhD Lindsay Pease, PhD Brittany Hanrahan, PhD Jed Stinner, PhD Katie Rumora, MS Phil Levison, MS Sara Henderson, MS Eric Fischer, MS Marie Pollock, MS Elizabeth Callow Mark Day SOIL DRAINAGE RESEARCH UNIT Funding partners USDA-Natural Resources Conservation Service CEAP - Conservation Effects Assessment Project MRBI: Mississippi River Basin Initiative 201/202 EOF activities USDA-Agriculture Research Service 4R Research Fund (IPNI and Fertilizer Industry) The Nature Conservancy Becks Hybrids/Ohio State University Ohio Agri-Businesses Ohio Corn and Wheat Growers CIG: 69-3A75-12-231 (OSU) CIG: 69-3A75-13-216 (Heidelberg University) Ohio Soybean Association U.S. Environmental Protection Agency: DW-12-92342501-0
- 22. Contact Information: Emily Duncan 590 Woody Hayes Dr. Columbus, OH 43210 emily.duncan@ars.usda.gov SOIL DRAINAGE RESEARCH UNIT
Editor's Notes
- So to set the stage: all of the field sites are located in the western Lake Erie Basin which includes parts of Michigan, Indiana and Ohio… Lake Erie has had a resurgence in of harmful algal blooms since the 1970s when there was a big push to adopt BMPs to reduce particulate and total P.
- However, while TP has declined dissolved reactive P has increased over the last decade or so, due to a combination of factors: change in rainfall distribution during the year, legacy of over application of P, increased applications of fertilizer and manure without incorporation in the fall and winter; a buildup of P in the soil surface with conversion to no till planting These factors helped to contribute to a “do not drink water advisory” issued by the city of Toledo in 2014. In this photo you can see a water intake location for the City and the green water
- ARS scientists established an edge-of-field research network to quantify the impact of agricultural crop production on water quality. This network will allow ARS to develop mutually beneficial solutions that protect public health and aquatic ecosystems while ensuring sustained agricultural production. LAKE EOF Binational annex 4 agreement
- Numbers in green = median value Blue = threshold (Tri state Annex target) Concentrations greater in surface than subsurface
- However, when you look at loads, subsurface loads are > surface loads (adding flow into the equation)
- Talk through the dashed lines first (define them) Annex 4 DRP and TP recs Then the STP recs Then how STP can pose environmental risk But that STP can be above and below the thresholds and still pose environmental risk (or not)
- Talk through the dashed lines first (define them) Annex 4 DRP and TP recs Then the STP recs Then how STP can pose environmental risk But that STP can be above and below the thresholds and still pose environmental risk (or not)
- Talk through the dashed lines first (define them) Annex 4 DRP and TP recs Then the STP recs Then how STP can pose environmental risk But that STP can be above and below the thresholds and still pose environmental risk (or not)
- Talk through the dashed lines first (define them) Annex 4 DRP and TP recs Then the STP recs Then how STP can pose environmental risk But that STP can be above and below the thresholds and still pose environmental risk (or not)
- Previous papers have investigated P stratification, but have not defined severity. All of our agronomic soils will be stratified, but how severe? And does that matter in relation to what we measure in EOF field losses Cite dave baker 2017 and doug smith unpublished? Dimensionless value, smaller number = less stratification, larger = greater stratification Tallied # of fields in each ranking stratification ranking for each fertilizer rec zone. Buildup maintenance and drawdown
- P stratification ranged from 0.93-3.9 STP influenced event mean DRP concentration in surface flows, but soil sample depth had no effect on DRP Hypothesized that surface runoff DRP would be strongly related to 0-5 cm depth STP and potentially increase with event size. Across surface flow percentiles we found that Event mean DRP concentration increased with STP with no effect of depth, We also investigated if the influence of STP on event mean DRP concentration varied with flow event size using ANCOVA We hypothesized that the relationship between STP and DRP would increase with event size. However we found that DRP was similarly and strongly influenced by STP and that there was no effect of event size. TILE FLOW: hypothesized hat concentrations in tile flow would increase with increasing STP concentrations. We found that DRP was strongly influenced by STP, and the effect of depth was only evident with 75th percentile flows. Though the relationship between DRP and STP did not vary with soil sampling depth within any flow ‘category’. STP explained 21-48% of the variation in DRP EMC in tile flows STP and DRP would incrase with event size in tile drainage. We found that the influence of STP on DRP concentration did not vary with event size at the 0-5 cm depth, nor did it influence the event size at the 5-20 cm depth
- Did not predict avg annual DRP EMC or 50th, 75th , 95th percentile concentrations
- Median P stratification from surface application of nutrients was statistically greater compared with fields that incorporated and the two fields without P application (Kruskal-wallis, p<0.05) Fields that practiced minimum tillage had slightly greater P stratification values (median = 1.94) than conventional (1.56), no-till (1.86) and rotational tillage (1.68), but there was no significant (P = 0.38) relationship with respect to tillage (Figure 4b).
- STP influenced event mean DRP concentration in surface flows, but soil sample depth had no effect on DRP Hypothesized that surface runoff DRP would be strongly related to 0-5 cm depth STP and potentially increase with event size. Across surface flow percentiles we found that Event mean DRP concentration increased with STP with no effect of depth, We also investigated if the influence of STP on event mean DRP concentration varied with flow event size using ANCOVA We hypothesized that the relationship between STP and DRP would increase with event size. However we found that DRP was similarly and strongly influenced by STP and that there was no effect of event size. TILE FLOW: hypothesized hat concentrations in tile flow would increase with increasing STP concentrations. We found that DRP was strongly influenced by STP, and the effect of depth was only evident with 75th percentile flows. Though the relationship between DRP and STP did not vary with soil sampling depth within any flow ‘category’. STP explained 21-48% of the variation in DRP EMC in tile flows STP and DRP would incrase with event size in tile drainage. We found that the influence of STP on DRP concentration did not vary with event size at the 0-5 cm depth, nor did it influence the event size at the 5-20 cm depth