3/21/2013 webinar overview · many sources of variation in n availability and crop needs...
TRANSCRIPT
Cornell Adapt‐N Intensive Workshop by Webinar:
Precision Nitrogen Management in CornUsing the Adapt‐N Tool
Adapt‐N.cals.cornell.edu
Presenters: Bianca Moebius‐Clune & Harold van Es
3/21/2013 Webinar Overview
Agenda Eastern Time Central Time
Overview of N concerns, N dynamics & Tools for N management
11:00 – 11:40am 10:00 – 10:40am
What is Adapt‐N? Interface overview 11:40 – 12:10pm 10:40 – 11:10pm
2011 & 2012 Adapt‐N on‐farm trial results 12:10 – 12:50pm 11:10 – 11:50pm
Networking Lunch 12:50 – 1:20pm 11:50 – 12:20pm
Inner workings of Adapt‐N and using the tool effectively
1:20 – 2:00pm 12:20 – 1:00pm
Hands‐on exercise* on using Adapt‐N, evaluation and surveys
2:00 – 3:00pm 1:00 – 2:00pm
Adjourn, additional time for Q&A 3:00pm 2:00pm
*Do you have an Adapt‐N account yet? If not, email adapt‐[email protected] to request one and get on our announcement e‐list.
Acknowledgements
Thanks to our funders:• New York Farm Viability Institute• USDA‐NRCS Conservation Innovation Grants program• USDA‐NIFA Agriculture and Food Research Initiative• USDA‐NIFA Special Grant on Computational Agriculture (Rep. Maurice Hinchey)• Hatch – Smith Lever Funds• Northern NY Agricultural Development Program• International Plant Nutrition Institute• Walton Family Foundation
Thanks to the tool developers and testers:• Jeff Melkonian (Modeler)• Art DeGaetano (Climate data)• Laura Joseph (Adapt‐N tool interface programmer)• Field Partners from Cornell Cooperative Extension, MGT Envirotec, Western NY Crop Management Association, Champlain Valley Agronomics, and others
• Growers hosting trials and providing feedback
Overview of N Concerns, N Dynamics and Tools for N Management
Nitrogen Concerns in Corn Production Systems
Agronomic/Economic
• ~ $5 billion/yr of N fertilizer applied to corn; large input costs for farmer
• N use efficiency low (30‐70%)
• High uncertainty, and sensitivity to climate change
Environmental (negative externalities)
• Largest energy input into cropping system
• Greenhouse gas emissions (esp. N2O)
• High groundwater nitrate levels
• Hypoxia/anoxia in estuaries
Water Quality Concerns Not Diminishing
Net Change in MRB Flow‐Normalized Nitrate Concentration and Flux between 1980 and 2008 (Sprague et al., 2011)From: Dubrovsky et al., 2010,
based on NAWQA data:
“Despite major Federal, State and local efforts and expenditures to control sources and movement of nutrients within our Nation’s watersheds, national‐scale progress was not evident in this assessment”
Hypoxia Zones in USA
David et al. J. Environ. Qual. 39:1657–1667 (2010)
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Riverine N Yield in the MRBArea of Gulf Dead Zone (NOAA, 2012)
Agricultural GHG Emissions (2008)
Nitrogen application to US agricultural lands in 2008 had a greater global warming impact than the entire US aviation industry (EPA, 2010)
36%
44%
20%
CH4
N2O
CO2
Del Grosso et al.,GBC 2010
Nitrous Oxide Losses Increase Exponentially With N Rate Beyond a “Critical” Value
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Snyder et al., 2009, based on data by Bouwman et al., 2002
Key Points: • Environmental loss can be minimized while optimum yield is supported• Finding “sweet spot” is critical• Perception is that farmers over‐apply N rates
Reasons for Farmer Tendency to Over‐Apply N:Coffee Shop Wisdom on Risk and Risk Perception
• With uncertainty around the optimum N rate, the profit losses from under‐fertilizing (yield penalty) are greater than those from over‐fertilizing (unnecessary fertilizer expense).
• Under‐fertilization results in highly visible leaf yellowing, while over‐fertilization is not noticeable.
– Farmers tend towards the highest rate
– Consultants cannot afford to be “wrong” with
low recommendation
• Fertilizer dealers have additional incentives
to suggest high rates or encourage suboptimal application timing
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60
80
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0 50 100 150 200 250 300
Corn N Response and Agronomic Optimum N Rate
Yield (bu/ac)
N Rate (lbs/ac)
Distribution of Economic Optimum N Ratesfertilizer = $0.60/lb; corn = $6/bu
from: http://extension.agron.iastate.edu/soilfertility/nrate.aspx
corn after corn Corn after soybean
Many sources of variation in N availability and crop needs generalized recommendations are too simplistic
• Organic amendments (manure, compost, etc.)
• Crop rotations
• Soil type differences
• Soil organic matter contents
• Soil and crop management (tillage, planting date, etc.)
• Weather:
– Temperature
– Precipitation!
Interactions are complex and nonlinear!
Weatherand Nitrogen
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Corn N Uptake ‐ Illinois
Average yield = 230 bu/ac
Bender et al. Better Crops 2013 (1)
Spring Summer Fall
corn N uptake
Plant N
Crop N uptake patterns ……
Spring Summer Fall
soil mineral N, normal year, no
manure
corn N uptake
Amount of N
Fertilizer Needed…
… in normal
year
Soil or plant N
SOM mineralization provides much of corn N needs……
Critical Time
Period –N builds up in soil before corn uptake
Spring Summer Fall
soil mineral N, normal year, no
manure
soil mineral N,wet spring
corn N uptake
Amount of N
Fertilizer Needed…
… in normal
year
soil or plant N
… in year with wet spring
Need for supplemental N fertilizer depends on early season weather …
Critical Time
Period –N builds up in soil before corn uptake
Spring Summer Fall
soil mineral N and pre-plant fertilizer,
normal year, no manure
soil mineral N,wet spring
corn N uptake
soil or plant N
Early application of N risks major losses……fertilizer or manure
N excess “insurance”… in normal year
… in year with wet spring
N deficiency
N deficiency
Meta‐analysis of 51 corn N response studies in North America
(Tremblay et al. 2012, Agronomy J.)
“Soil and weather properties were found to have a fairly pronounced effect on corn response to N fertilization.”
Medium and fine‐textured soils
B.D. Kay, A.A. Mahboubi, E.G. Beauchamp, and R.S. Dharmakeerthi. 2006. Soil Sci. Soc. Am. J. 70:1210–1221. (adapted by T. Bruulsema)
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Plant‐available N, lb/A
Cumulative rainfall planting to sidedress, inches
Weather effect on N supply depends on
soil organic carbon (SOC)
3.0
2.5
2.0
1.5
1.0
SOC, %
to re‐iterate….
Corn nitrogen use
• is impacted by climate change (weather extremes)
and
• contributes to climate change (through N2O emissions)
Opportunities exist for both adaptation and mitigation
Predicting N Needs for Corn:Precision Improves over Time
low
high
fall winter spring summer fall
snow summer drought
spring rains
Main Factors:
noninterventionintervention
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Greater Sidedress Flexibility with High‐Clearance Equipment
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• Soil: Honeoye silt loam• Grains cultivar: mid-maturity, planted at 30,000 plants/ac,
YearMay/June Precip (mm)
July/AugPrecip (mm)
Optimum N (lb/ac)
A) 173 366 ?
B) 260 278 ?
Years A and B had equivalent amounts of rainfall during the whole growing season, but distributed as follows:
POLL #1: How did the Optimum N rates compare? What do you think? a) Optimum N rates are the same because total rainfall was the sameb) Optimum N rate was higher in year Ac) Optimum N rate was higher in year B
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Two years with the same total precipitation during the growing seasons:
• Soil: Honeoye silt loam• Grains cultivar: mid-maturity, planted at 30,000 plants/ac• More rain in July/August is less likely to cause saturation and
subsequent N losses, because roots are deep, and transpiration is rapid.
YearMay/June Precip (mm)
July/AugPrecip (mm)
Optimum N (lb/ac)
A) 173 366 90
B) 260 278 160
Simulated Scenarios (PNM model) show: Total precipitation over the season matters less than how much rain falls when!
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Estimating Economic Optimum N Rates:
Static Approaches
Mass‐Balance Approach: Based on a yield goal, minus credits given for non‐fertilizer N sources such as mineralized N from soil organic matter (SOM), preceding crops, and organic amendments.
Maximum Return to N (MRTN) Approach:• Based on extensive multi‐year and multi‐location field trials, curve‐fitting, and economic
analyses.
• Rate with largest average net return over many years is the MRTN
• Adjustments based on yield expectations, price ratios, and other N contributions may be considered.
• Used in the major corn belt states.
Model Approach (Maize‐N):Use of historical climate data, soil and management information to estimate yield potential and N needs
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Economic optimum N rate (lb/acre)
Gra
in y
ield
(bu
/a)
Medium High
Soil yield potential From: Bundy
Tools for AdaptiveN Management in Corn
Pre‐Season:• Pre‐Plant Soil Nitrate Test
• Potential Mineralization (incubation and extraction tests, ISNT, Solvita, etc.)
In‐Season: • PSNT‐LSNT
• Leaf Canopy Reflectance Sensing
• Models (Adapt‐N)
End‐of‐Season: • Late Season Stalk Nitrate Test
• Models (Adapt‐N) Iowa Soybean Assn.
Questions?• What valuable information is gained at each time?• What information is not gained?
Nitrogen Managementwith Computational Tools
• Move from generalized to site‐specific recommendations
• Allows for adaptive, real‐time management‐ Weather conditions
‐ Local soils and crop management
• Universal process‐based approach‐ Incorporates system complexity and variability
through relevant processes
• In‐season and post‐season evaluations
• Low cost
• Allows for progressive refinement29