Impacts of 4R Nitrogen Management on Drainage Water Quality

Department of Agricultural and Biosystems Engineering College of Agriculture and Life Sciences Impacts of 4R Nitrogen Management on Drainage Water Quality Matthew Helmers Dean s Professor, College of Ag. & Life Sciences Professor, Dept. of Ag. and Biosystems Eng. Iowa State University

Soil Nitrate Production vs. Crop Nitrate Uptake Rate of soil nitrate production from native soil organic matter Rate of corn or soybean nitrate uptake The majority of nitrate used by corn and soybean comes from soil nitrate production. Corn gets the difference from fertilizer while soybean gets the difference from legume fixation of atmospheric nitrogen. March February In the shaded areas, the soil produces nitrate, but there is no crop to use it. As a result, some nitrate is lost to waterways.

Replicated subsurface drainage plots to evaluate performance of various in-field management practices NWRF Drainage Gilmore City DRF NERF Drainage COBS SERF Drainage 172 monitored plots ~4000 samples per year

Replicated subsurface drainage plots to evaluate performance of various in-field management practices NWRF Drainage Gilmore City DRF NERF Drainage COBS SERF Drainage

Twenty-Seven Year Summary Drainage (in) 30 25 20 15 10 5 0 1990 1991 Drainage Nitrate-N Concentration Nitrate-N Loss 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Avg 30 25 20 15 10 5 0 Nitrate-nitrogen Concentration (ppm) 120 100 80 60 40 20 0 Nitrate-nitrogen Loss (lb-n/ac)

Twenty-Seven Year Summary Drainage (in) 30 25 20 15 10 5 0 1990 1991 Drainage Nitrate-N Concentration Nitrate-N Loss 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Avg Combined Corn-Soybean System Same N management Early Spring Sidedress at 150-160 lb-n/acre 30 25 20 15 10 5 0 Nitrate-nitrogen Concentration (ppm) 120 100 80 60 40 20 0 Nitrate-nitrogen Loss (lb-n/ac)

Nitrate Response to Nitrogen

Results Nitrogen source Averaged over the corn-soybean rotation 25 Flow-weighted Nitrate-N Concentration (mg/l) 20 15 10 5 Urea Aqua-Ammonia Poly-Coated Urea 0 2011 2012 2013 2014 2015 Avg

Impact of Application Timing: 2006-14 125 lb-n/acre 150 lb-n/acre

Soil Nitrate Production vs. Crop Nitrate Uptake Addition of a Cover Crop Rate of soil nitrate production from native soil organic matter Rate of corn or soybean nitrate uptake Cover crops can use nitrate when corn and beans are not growing, thus reducing the asynchrony between soil nitrate production and crop nitrate uptake. Cover crop nitrate use Cover crop nitrate use March February In the shaded areas, the soil produces nitrate, but there is no crop to use it. As a result, some nitrate is lost to waterways.

Winter Cereal Rye Cover Crops Ames Gilmore City

Impacts of Cover Crops on Nitrate-N Load in Drainage Water Gilmore City 36% Reduction 34% Reduction

Impacts of Cover Crops

Treatments at the Gilmore City Research Facility for Crop Years 2018-?. Treatment Number* 1,2 3,4 5,6 7,8 Tillage Cover Crop Nitrogen Application Time Conventional tillage Conventional tillage Conventional tillage Conventional tillage _ Rye planted into standing corn and beans and tilled prior to planting of cash crop in Spring Nitrogen Application Rate (lb/acre) Fall - Anhydrous 150 Fall - Anhydrous 150 with Inhibitor Spring - Anhydrous 150 Spring - Anhydrous 150 9,10 No-till _ Spring - Anhydrous 150 11,12 No-till 13,14 15,16 17 18 Conventional tillage Conventional tillage Conventional tillage Orchardgrass + Red/Ladino clover Rye planted into standing corn and beans _ Spring - Anhydrous 150 Spring - Anhydrous 150 with Inhibitor Spring - Anhydrous 150 No N - no fertilizer

Replicated subsurface drainage plots to evaluate performance of various in-field management practices NWRF Drainage Gilmore City DRF NERF Drainage COBS SERF Drainage

Treatments Treatment Number Tillage Nitrogen Application Time 1 Conventional tillage* Fall (anhydrous ammonia with nitrapyrin)** 2 Conventional tillage Spring (anhydrous ammonia) 3 Conventional tillage Split with variable N at sidedress (40 lb/acre of urea 2x2 starter at planting plus in-season agrotain treated urea) Nitrogen Application Rate (lb N/acre)* 135 135 135 4 Conventional tillage None 0 * Fall chisel corn stalks with spring disk/field cultivate, and spring disk/field cultivate soybean stubble. **In fall of 2014 freezing conditions occurred early and prevented fall application. Application occurred in early spring 2015.

Flow-weighted Nitrate-N Concentration *Means with the same letter in the same year are not significantly different, P=0.05.

Replicated subsurface drainage plots to evaluate performance of various in-field management practices NWRF Drainage Gilmore City DRF NERF Drainage COBS SERF Drainage

Impact of Land Management

Replicated subsurface drainage plots to evaluate performance of various in-field management practices NWRF Drainage Gilmore City DRF NERF Drainage COBS SERF Drainage

Treatments at the NERF Research Facility for Crop Years 2016-?. System Application timings and source of N Crop in 2016 1 Spring (UAN) Corn Soybean 2 Fall (early fall manure) Corn 3a 3b 4a Fall (manure w/instinct) Spring manure Fall (manure) Soybean Cont. Corn Cont. Corn Cont. Corn 4b Fall (manure) - gypsum Cont. Corn at 1 ton/acre 5 Fall (early fall manure) Corn/Rye cover Soybean/ Rye cover 6 Fall (late fall manure) Corn Soybean Tillage Chisel Plow Field Cultivate No-till No-till Chisel Plow Chisel Plow Chisel Plow Chisel Plow No Till No Till No Till No Till Nitrogen Application rate, lb/acre 150-150 - 200 200 200 200 150-150 -

Timing of Fall Manure Application Project Funded by: Iowa Pork Producers Association

To Reach our Goals WE NEED IT ALL!! N Management Cropping practices/landuse Edge-of-Field Practices

Department of Agricultural and Biosystems Engineering Resources 10 Ways to Reduce Nitrate Loss - http://draindrop.cropsci.illinois.edu/wp- content/uploads/2016/09/ten-ways-to-reduce- Nitrate-Loads_IL-Extension-_2016.pdf Drainage Water Quality Impacts of Various In-Field Nutrient Management Practices Agricultural Drainage Research and Demonstration Site Gilmore City AE 3614 Comparison of Biofuel Systems Site AE 3615 Northeast Research and Demonstration Farm AE 3616 Northwest Research and Demonstration Farm AE 3617 Southeast Research and Demonstration Farm AE 3618

Department of Agricultural and Biosystems Engineering Discussion mhelmers@iastate.edu Twitter: @ISUAgWaterMgmt Website: http://agwatermgmt.ae.iastate.edu/

Long-Term Trends

Relationship to Precipitation

Drainage as Function of Precipitation 30 Subsurface Drainage (in) 25 20 15 10 5 0 15 20 25 30 35 40 45 Precipitation (in)

Nitrate-N Loss as Function of Precipitation 100 Nitrate-N Loss (lb/acre) 80 60 40 20 0 15 20 25 30 35 40 45 Precipitation (in)

Nitrate-N Loss as Function of Drainage 100 Nitrate-N Loss (lb/acre) 80 60 40 20 0 0 5 10 15 20 25 30 Drainage (in)

Nitrate-N Concentration as Function of Precipitation 25 Nitrate-N Concentration (mg/l) 20 15 10 5 0 10 20 30 40 50 Precipitation (in)

Nitrate-N Concentration as Function of Drainage 25 Nitrate-N Concentration (mg/l) 20 15 10 5 0 0 5 10 15 20 25 30 Drainage (in)

Temporal Changes

N Concentration Nitrate-nitrogen Concentration (ppm) 30 25 20 15 10 5 0 1990 1995 Nitrate-N Concentration 2000 2005 2010 2015

N Loss 120 Nitrate-nitrogen Loss (lb-n/ac) 100 80 60 40 20 0 1990 1995 Nitrate-N Loss 2000 2005 2010 2015

Corn Yield 200 Corn Yield (bu/acre) 180 160 140 120 100 1990 1995 2000 2005 2010 2015

N Output with Grain N Output with Corn (lb/acre) 140 120 100 80 60 40 20 0 1990 1995 2000 2005 2010 2015

N Surplus N Fert. Input - N Grain Output (lb/acre) 140 120 100 80 60 40 20 0 1990 1995 2000 2005 2010 2015

N Loss versus Surplus 100 Nitrate-N Loss (lb/acre) 80 60 40 20 0 20 40 60 80 100 120 N Surplus (N Fert. - N Corn Output) (lb/acre)

N Concentration versus Surplus 25 Nitrate-N Concentration (lb/acre) 20 15 10 5 0 20 40 60 80 100 120 N Surplus (N Fert. - N Corn Output) (lb/acre)

N Rate versus Load 100 Nitrate-N Loss (lb/acre) 80 60 40 20 0 0 50 100 150 200 250 N Application Rate (lb/acre)

N-Rate versus Concentration 30 Nitrate-N Concentration (mg/l) 25 20 15 10 5 0 0 50 100 150 200 250 300 N Application Rate (lb/acre)

N Surplus versus Load 100 Nitrate-N Loss (lb/acre) 80 60 40 20 0-50 0 50 100 150 200 N Surplus (lb/acre)

N Surplus versus Concentration 30 Nitrate-N Concentration (mg/l) 25 20 15 10 5 0-50 0 50 100 150 N Surplus (lb/acre)

Other Practices being Studied at ISU

Replicated subsurface drainage plots to evaluate performance of various in-field management practices NWRF Drainage Gilmore City DRF NERF Drainage COBS SERF Drainage

Drainage Water Management

Impacts of DWM

Nitrate Removal Wetland

Hydrologic and nutrient loading rates are major drivers of wetland performance. Wetlands occupying only 1% of landscape can reduce long term average nitrate loads about 52%. From: W.G. Crumpton

Drainage Area Wetland

SERF Wetland Performance

SERF Wetland Performance 18 Nitrate-N Concentration (ppm) 16 14 12 10 8 6 4 2 0 Inflow Outflow

Saturated buffers

Subsurface Drainage Bioreactor From Christianson and Helmers, 2011 Illustration by John Petersen (www.petersenart.com)

Example Bioreactor 2D Performance Graph 2 30 Nitrate-N Concentration (mg/l) 25 20 15 10 5 0 Inflow Outflow Department of Agricultural and Biosystems Engineering

Drainage water recycling

Department of Agricultural and Biosystems Engineering Discussion mhelmers@iastate.edu Twitter: @ISUAgWaterMgmt Website: http://agwatermgmt.ae.iastate.edu/

Coordinated Site Network for Studying the Impacts of 4R Nutrient Management on Crop Production and Nutrient Loss Dr. Matt Helmers, Professor Iowa State University Dr. Sylvie Brouder, Professor Purdue University Dr. Laura Christianson, Assistant Professor University of Illinois Dr. Cameron Pittelkow, Assistant Professor, University of Illinois Dr. Kelly Nelson, Professor University of Missouri Dr. Dan Jaynes, Soil Scientist USDA-ARS National Laboratory for Ag. and the Environment Dr. John Kovar, Soil Scientist USDA-ARS National Laboratory for Ag. and the Environment Lowell Gentry, Research Scientist University of Illinois Dr. Craig Drury, Research Scientist Agriculture and Agri-Food Canada Dr. Fabian Fernandez, Assistant Professor University of Minnesota Dr. Alison Eagle, Scientist, Sustainable Agriculture, Ecosystems Program, EDF Dr. Jeffrey Volenec, Professor Purdue University Dr. Cliff Snyder, Nitrogen Program Director for the International Plant Nutrition Institute (IPNI)

Justification Eagle et al. (2015) noted that only one study reported simultaneous nitrous oxide (N 2 O) emissions and NO 3 leaching losses, along with crop yield information. (4R Research Funded Project) In addition, we are aware of no studies explicitly aimed at understanding the interactions between 4R management strategies, soil health, drainage water quality, and nitrous oxide emissions

Objectives Our objective is to: Quantify the impact of 4R Nutrient Stewardship on crop yield, soil health, nutrient use efficiencies, nutrient losses with leaching, and gaseous nitrogen losses across a network of coordinated studies in the major corn producing area of North America. Figure 1. Location of study sites. Project Funded by the FFAR (Foundation for Food and Agriculture Research) and The 4R Research Fund