Using Paired Edge of Field Data to Assess Impacts of Management on Surface and Subsurface P Loss Kevin W. King, Mark R. Williams, and Norm R. Fausey USDA ARS Soil Drainage Research Unit Columbus, OH
Edge-of-field research 40 fields (20 paired fields) representative of Ohio crop production agriculture Surface runoff and tile discharge measurements Using a before-after controlimpact study design
Funding Sources: 4R Research Fund USDA ARS: USDA Agriculture Research Service CEAP: Conservation Effects Assessment Project EPA: DW 12 92342501 0 Ohio Agri Businesses Ohio Corn and Wheat Growers CIG: 69 3A75 12 231 (OSU) CIG: 69 3A75 13 216 (Heidelberg University) MRBI: Mississippi River Basin Initiative The Nature Conservancy Becks Hybrids/Ohio State University Ohio Soybean Association
Phosphorus Concentrations 2.5 2.0 1.5 0.5 surface tile Event mean concentration (mg/l) DRP TP
Annual DRP loading (kg/ha/yr) Annual TP loading (kg/ha/yr) 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 0.8 0.6 0.4 0.2 4.0 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 0.8 0.6 0.4 0.2 Tile Surface P Tack Force recommendation A B C D E F G H I J K L M N O P Q
Effect of event size on surface losses 0.8 Discharge 0.6 0.4 0.2 2094 rainfall events greater than 6.3 mm (0.25 inches) Fraction of Annual 0.8 0.6 0.4 0.2 0.8 DRP TP Across all sites, rainfall events > 50.8 mm (2 inches) accounts for: 10.2% of all rainfall events 65% of discharge 0.6 64% of DRP load 0.4 0.2 65% of TP load <12.7 12.7-25.4 25.4-38.1 38.1-50.8 50.8-63.5 63.5-76.2 76.2-88.9 > 88.9 Event Size (mm)
Effect of event size on tile losses 0.8 0.6 0.4 Discharge 1601 rainfall events greater than 6.3 mm (0.25 inches) 0.2 Fraction of Annual 0.8 0.6 0.4 0.2 0.8 DRP TP Across all sites, rainfall events > 50.8 mm (2 inches) accounts for: 6% of all rainfall events 45% of discharge 0.6 33% of DRP load 0.4 0.2 33% of TP load <12.7 12.7-25.4 25.4-38.1 38.1-50.8 50.8-63.5 63.5-76.2 76.2-88.9 > 88.9 Event Size (mm)
4R Preliminary Findings Rate Timing Source Placement
Fertilizer Rate
Fertilizer Rate 500 400 300 Mehlich 3 STP (ppm) 180 160 140 120 100 80 60 40 20 0 0.2 0.4 0.6 0.8 Discharge:Precipitation Ratio <0.3 kg/ha >0.3 kg/ha tri-state critical level tri-state maintencance level
Discharge (m3/s) 2500 2000 1500 1000 500 0 2500 2000 1500 1000 500 discharge 20 15 10 5 0 0.4 0.3 0.2 0.1 NO3 + NO2 - N (mg/l) DRP (mg/l) 0 3/1/15 4/1/15 5/1/15 6/1/15 7/1/15 8/1/15 Data from Heidelberg Univ. Laura Johnson
Timing
180 Surface Losses Time of Application 160 140 120 100 80 60 4 kg/ha 0.56 kg/ha 0.50 kg/ha Greatest potential for surface and tile losses occurs with fall and winter application Mehlich 3 STP (ppm) 40 20 0 180 160 140 120 6 kg/ha Tile Losses 0.50 kg/ha Applying P in spring or after wheat harvest seems to minimize surface and tile losses 100 80 60 40 20 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Time of application
20 DRP concentration (mg/l) 15 10 5 1/3/12: 225# MAP 11/13/13: 193# MAP 0 0 20 40 60 80 100 120 140 Days since application
Placement
Broadcast variable rate application on May 6, 2014
4 part stratification M3P (ppm) Core depth (inches) 0-1 1-2 2-5 5-8 0 25 50 75 100 125 300 Median 60 54.5 49 34 26 Stratification evident even in the top 1 of soil (ANOVA, P<01, n=232) Although the degree of stratification varied some 85% of the samples had some degree of stratification Source: Johnson and Baker, Heidelberg University
Before P application & tillage (April 28 th ) After P application & tillage (May 12th) Discharge (mm) 1.4 1.2 0.8 0.6 0.4 0.2 1.4 1.2 0.8 0.6 0.4 0.2 TD1 Discharge Preferential flow DRP 1.45.00 1.2 4.00 1 0.8 3.00 0.6 2.00 0.4 0 0.2 TD2 00 0 0 20 40 60 80 0 20 40 60 80 Discharge DRP 1.4 140 1.2 120 1001 0.80 0.60 0.40 0.20 5.01.40 1.20 4.0 0 3.00.80 0.60 2.0 0.40 0.20 1401.40 1201.20 1000 80 0.80 60 0.60 40 0.40 20 0.20 TD1 1.405.0 1.20 4.0 0 0.80 3.0 0.60 2.0 0.40 0.20 0 0 10 20 30 0 10 20 30 Avg DRP (mg/l) = 8 Avg DRP (mg/l) = 8 Avg DRP (mg/l) = 0.58 Avg DRP (mg/l) = 2.12 DRP (mg/l) DRP (g/ha) 1.40140 1.20120 0100 0.8080 0.6060 0.4040 0.2020 TD2 5.0 4.0 3.0 2.0 140 120 100 80 60 40 20 DRP (mg/l) DRP (g/ha) 0 0 20 40 60 80 0 0 20 40 60 80 0 00 0 0 10 20 30 0 10 20 30 DRP Load (g/ha) = 12.6 DRP Load (g/ha) = 12.4 DRP Load (g/ha) = 18.2 DRP Load (g/ha) = 129.6
Fertilizer Source
Fertilizer Source (chronic vs acute risk) DRP Load (kg/ha) 6.0 5.5 5.0 3.0 2.0 DRP NO3-N Load (kg/ha) 120 110 100 90 80 70 60 50 40 30 20 10 0 NO3-N inorganic mixed organic
Structural and Other Management Drainage Water Mgt Gypsum Cover Crops
Drainage Water Management Quantify tile discharge and nutrient dynamics before and after implementation of drainage water management
DWM - Case Study Drainage area: B2 = 14 ha; B4 = 15 ha 0 90 180 m Legend Tile depth: 0.9 - m Ohio Ditch Tile outlet Drainage area Soil type: Bennington silt loam Pewamo clay loam Upper Big Walnut Creek Watershed B2 B4 Soil test P concentration: 60 mg/kg (0-20 cm) 2006-2008: Both sites were free draining 2009-2012: DWM was implemented at B4
DWM - Case Study Mean DRP conc. (mg L -1 ) 0.30 B2 0.25 B4 0.20 0.15 0.10 5 0 2005.520062006.520072007.520082008.520092009.520102010.520112011.520122012.5 Annual DRP load (kg/ha) 1.20 0.90 0.60 0.30 0 2006 2007 2008 2009 2010 2011 2012 Year Year DWM did not significantly affect DRP concentration 65-74% reduction in annual DRP load with DWM
Gypsum Treatment Mercer County Ohio >400 ppm Mehlich 3 in the top 8 inches Corn soybean rotation in a no till system Blount soil; randomly tiled June 2011 to October 2014 October 3 of 2013, 1 ton of gypsum was applied to treatment area Baseline period (86 rainfall events ) Treatment period (34 rainfall events)
Surface Tile Combined Treatment field DRP concentration (mg/l) DRP load (kg/ha) TP concentration (mg/l) 2.5 2.0 1.5 0.5 0.5 1.5 2.0 2.5 0.5 1.5 2.0 2.5 0.5 1.5 2.0 2.5 0.5 0.4 0.3 0.2 0.1 5.0 4.0 3.0 2.0 0.1 0.2 0.3 0.4 0.5 0.1 0.2 0.3 0.4 0.5 kn4-tp-cnc-c vs kn1-tp-cnc-c kn4-tp-cnc-t vs kn1-tp-cnc-t xp vs surf TP conc c xp vs surf TP conc t 0.1 0.2 0.3 0.4 0.5 Gypsum effect on surface drainage and P Significant increase in tile drainage discharge Significant decrease in DRP and TP event concentrations Significant decrease in DRP and TP loading 2.0 3.0 4.0 5.0 2.0 3.0 4.0 5.0 2.0 3.0 4.0 5.0 0.5 TP load (kg/ha) 0.4 0.3 0.2 0.1 kn4-tp-ld-c vs kn1-tp-ld-c kn4-tp-ld-t vs kn1-tp-ld-t xp vs surf TP load c xp vs surf TP load t 0.1 0.2 0.3 0.4 0.5 0.1 0.2 0.3 0.4 0.5 0.1 0.2 0.3 0.4 0.5 Control field
Cover Crops (what is the resource concern?) Positives Increase infiltration Reduce erosion Improve soil health Increase OM Negatives Increase DRP surface losses following freeze thaw cycles (Miller et al., 1994; Bechmann, et al 2005; Cavadini, 2013) Leachate concentrations of P differ depending on catch crop and soil (Riddle and Bergstrom 2013; Liu et al 2014) P concentration around tuber of tillage radish significantly greater than surrounding soil (White and Weil, 2011)
Conclusions P & N losses are impacted by: STP Connectivity to water Placement of P fertilizer Timing of fertilizer Rate of fertilizer Source and legacy effects
Conclusions Practices that will address excess P Adherence to tri state recommendations or lesser application Increased organic matter/carbon, cover crops, no till, etc Cover crops correct cover crop or blend is critical Gypsum water quality benefits are minimal but significant Avoiding fall and winter applications Accounting for manure in nutrient calculations Subsurface placement of nutrients (banding or injecting) Disconnecting hydrologic pathways (DWM, blind inlets, linear wetlands, water storage/increased OM)
Collaborators, Partners, and Outreach SWCDs OSU Extension and OARDC Agri businesses (Commodities, retailers) Ohio Farm Bureau TNC State agencies (ODNR, ODA, OEPA) NRCS (local, state, and federal) Crop consultants Producers/landowners Lake Improvement Other ARS locations NOAA and NWS Great Lakes Commission Great Lakes Protection Fund Greenleaf Advisors Multiple University Partners (OSU, Utoledo, Oklahoma State Univ., Univ. of Waterloo, NC State, Purdue Univ.) 4R Research Fund (IPNI, TFI) NCWQR at Heidelberg Agriculture and Agri Food Canada Consultants (CCAs, Limno Tech) USGS Private Industry (Agri Drain, ADS, Hancor, John Deere, The Andersons, Becks Hybrids) Gypsoil
Technical Support Staff Mark Day, Eric Fischer, Phil Levison, Paxton MacDonald, Katie Rumora, Marie Schrecengost, Jed Stinner Contact Information Kevin King 590 Woody Hayes Dr. Columbus, OH 43210 kevin.king@ars.usda.gov