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 (NO3

• )

Fertilizer Denitrification (NO3

• )

Manure Volatilization (NH3) Mineralization Immobilization (tie-up) Atmospheric Fixation

Nitrification Assimilation NH4

+  NO2

•  NO3
• Plant uptake of N

Nitrosomonas Nitrobacter

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, NO3-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

• ther 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

1 17 4 18 C 4 19 2 20 3 21 Trt # Plot #

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 NO3-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. NO3-N conc. lb /A bu/A mg/L

• 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

• 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 NO3 (0-5’ depth) as affected by N rate (Port Byron)

2006-10 average, Olmsted County

Nitrogen rate, lb N ac-1

30 60 90 120 150 180

Resiual soil nitrate-N (0-5'), lb ac-1

20 40 60 80 100 120

Relative yield, %

40 60 80 100

Nitrate Yield

97.4% of max yield

Relative corn yield following corn & residual soil NO3 (0-5’ depth) as affected by N rate (Port Byron sil)

2007-10 average, Olmsted County

Nitrogen rate, lb N ac-1

40 80 120 160 200

Resiual soil nitrate-N (0-5'), lb ac-1

20 40 60 80 100 120

Relative yield, %

40 60 80 100

Nitrate Yield

98.4% of max yield

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

• f 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?