Management, and Policy: A Historical and Regional Perspective Gyles - PowerPoint PPT Presentation

Nitrogen Science, Management, and Policy: A Historical and Regional Perspective Gyles Randall Univ. of Minnesota, Soil Scientist and Professor Emeritus Wisconsin Nitrogen Science Summit March 28, 2014

Goals • History of N & nitrate environment • N cycle and its complexities • Drivers of N loss • Developing a fertilizer N mgmt. plan • Role of stakeholders • N research to establish BMP’s • Future: research, policy, regulation

History 60’s: Encourage fertilizer use Nitrate leaching in sandy soils Sampling tile drainage for nitrate analysis 70’s: Greater environmental concern - both leaching & tile drainage - WI, NE, IA, IN, IL, & MN - B. Commoner vs. S. Aldrich debate - defensiveness increases

80’s: Environmental concerns expand - both ground water & surface water - Big Spring (IA), Hall Co. (NE) - SE Minnesota 90’s - 00’s: Hypoxia in Gulf of Mexico - Mississippi River Basin - focus on tile drainage 10’s: Nutrient reduction strategies Water quality standards

Nitrogen Cycle Loss Pathways Inputs - ) Leaching (NO 3 Fertilizer - ) Denitrification (NO 3 Manure Volatilization (NH 3 ) Mineralization Immobilization (tie-up) Atmospheric Fixation Nitrification Assimilation Nitrosomonas Nitrobacter +  NO 2 -  NO 3 - Plant uptake of N NH 4

Drivers of N Loss • Affected by N management practices - source, rate, time, and placement of N - type of manure • Affected by soil properties (texture)* - internal drainage (well vs. poorly) • Influenced by weather, primarily precip.* * = Non-controllable factors

4R’s – Right Source – Ensure a balanced supply of essential nutrients, considering both naturally available sources and the characteristics of specific products, in plant available forms. – Right Rate – Assess and make decisions based on soil nutrient supply and plant demand. – Right Time – Assess and make decisions based on the dynamics of crop uptake, soil supply, nutrient loss risks, and field operation logistics. – Right Place – Address root-soil dynamics and nutrient movement, and manage spatial variability within the field to meet site-specific crop needs and limit potential losses from the field.

Lynn Betts, NRCS

Randall

Minnesota Develops N Mgmt. Plan (1989) • response to legislative concern & direction • goals were to: (1) collect & discuss information, (2) develop BMP’s & (3) establish “regulatory” guidelines • involved many stakeholders - State & fed. agencies, university, commodity groups, watershed districts, lake assn’s, & environmental groups • many meetings: Twin Cities & out-state hearings

N Mgmt. Plan Products • BMP’s were developed for five state regions plus sandy soils. - printed as extension bulletins & widely distributed - published by Minn. Legislature to give statutory prominence • A water resource protection plan was developed for regulatory/oversight purposes. - never implemented for various reasons • Heightened respect among groups/ participants.

Region Specific BMPs for N

Role of Stakeholders • Represent their group with integrity • Engage in the process with sincerity • Communicate findings, results, and interpretation without bias • Participate to the END

Characteristics for Success • Inclusive leadership • Willingness to listen carefully • Being polite & patient • Refrain from sidetracking discussion • Willing to compromise during process • Ability to discern between myth & fact • Understand where others are coming from

Role of University & Agencies • Be willing to fund and/or conduct research critical to answering gaps in knowledge • Conduct research that examines the production, economics, and environmental consequences of various crop, soil, water, and nutrient management practices, simultaneously • Deliver extension programs that address production, economic, and environmental facets, simultaneously!

Examples of BMP research

Effect of CROPPING SYSTEM on drainage volume, NO 3 -N concentration, and N loss in subsurface tile drainage during a 4-yr period (1990-93) in MN. Cropping Total Nitrate-N System discharge Conc. Loss Inches ppm lb/A Continuous corn 30.4 28 194 Corn – soybean 35.5 23 182 Soybean – corn 35.4 22 180 Alfalfa 16.4 1.6 6 CRP 25.2 0.7 4

Conclusions • Cropping system has greater effect on hydrology and nitrate losses than any other management factor! (RISK) • Perennial crops (alfalfa and grasses) compared to row crops (corn and soybean) reduce – Drainage volume by 25 to 50% – Nitrate loss by > 95%

Randall

Corn-Soybean Rotation Drainage Study, Waseca Trt # 1 4 2 3 4 Plot # 17 C 19 20 21 18 5’ 20’

Time and Rate of N Application and Nitrification Inhibitors (N-Serve)

Effect of time of AA application and N-Serve on corn yields after soybean from 1987-2001 at Waseca Time of N Application Parameter Fall Fall+N-Serve Spring 15-Yr Avg. Yield (bu/A) 144 153 156 15-Yr Avg. FW NO 3 -N Conc. (mg/L) 14.1 12.2 12.0 15-Yr N recovery in grain (%) 38 46 47 7-Yr Avg. Yield (bu/A)* 131 146 158 * Seven years when statistically significant differences occurred.

Attributes of Study • 15 years • Grain yield, nitrate-N conc. in tile water & N recovery • Probability of yield response to time of application & NI - 7 of 15 yrs • Can calculate economics (gain or loss)

Time, Rate, and Source of N with & w/o a Nitrification Inhibitor

Effect of N rate on yield of corn after soybean, net return to fertilizer N, and nitrate-N concentration in tile drainage at Waseca (2000 – 2003). N Treatment 4-Yr Yield 4-Yr FW Time Rate N-Serve Avg. NO 3 -N conc. lb /A bu/A mg/L --- 0 --- 111 --- Fall 80 Yes 144 11.5 Fall 120 Yes 166 13.2 Fall 160 Yes 172 18.1 Spr. 120 No 180 13.7

Continuous corn yield and F.W. annual nitrate-N concentration in tile drainage water as affected by time of urea application and a nitrification inhibitor at Waseca in 2013. N Treatment Grain Nitrate-N Rate Time NI Yield Conc lb/A bu/A ppm 0 -- -- 68 3.6 200 F N 160 29 200 F Y 166 25 200 S N 195 18 200 S Y 192 16

Region Specific BMPs for N

Proposed BMP’s for South -Central MN • Recommended – Spring preplant or split applications of ammonia, urea, or UAN are highly recommended. – Incorporate broadcast urea or preplant UAN within three days. – Apply sidedress application before corn is 12” high. – Inject or incorporate sidedress applications of urea or UAN to a minimum depth of 4 inches.

Proposed BMP’s for South -Central MN cont. • Recommended, but with greater risk – Fall application of AA + N-Serve after soil temperature at 6-inch depth is below 50 ° F. – Side dressing all N before corn is 12 inches high. • Not recommended – Fall application of urea, UAN, or anhydrous ammonia without N-Serve

Well drained soils, SE Minn.

Relative corn yield following soybean & residual soil NO 3 (0- 5’ depth) as affected by N rate (Port Byron) 120 100 Nitrate Resiual soil nitrate-N (0-5'), lb ac-1 Yield 100 Relative yield, % 97.4% of max yield 80 80 60 60 40 20 40 0 0 30 60 90 120 150 180 2006-10 average, Nitrogen rate, lb N ac-1 Olmsted County

Relative corn yield following corn & residual soil NO 3 (0- 5’ depth) as affected by N rate (Port Byron sil) 120 100 Nitrate Resiual soil nitrate-N (0-5'), lb ac-1 Yield 100 Relative yield, % 98.4% of max yield 80 80 60 60 40 20 40 0 0 40 80 120 160 200 2007-10 average, Nitrogen rate, lb N ac-1 Olmsted County

Decision Time • Guiding information is available • Risk and uncertainty - economic risk - environmental risk

Risks for Fall vs. Spring N • Agronomic • Economic • Environmental • Logistical • Psychological • Social Plus TRADITION!

Future Research • Determine critical geographic areas • Cropping systems • Leaching to ground water • Nitrous oxide emissions • Mineralization - manure

Corn yield at the zero-N rate as a percent of yield at EONR (0.10 price ratio). Previous Crop State Corn Soybean ---------- % ----------- Illinois 54 64 Iowa 45 75 Minnesota 60 76 Wisconsin 75 80

Future: Minnesota • Updated N Fertilizer Mgmt Plan (MDA) • Nutrient Reduction Strategy (MPCA) • $ & public opinion • Water quality standards for flowing waters

Questions?