Transcript Document

OVERSEER® Nutrient
Management Tool:
Present and future perspectives
Waikato Regional Council Presentation
25 October 2012
Philip Mladenov
Chief Executive
Contents
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What is OVERSEER®?
What does it do?
How well does it do it?
How is it being used?
OVERSEER® and regulation
Next steps
What is OVERSEER®?
A short history
• OVERSEER® started as a simple nutrient budgeting model
linked to fertiliser advice
• 15 years / $15 million invested
• Today OVERSEER® is a sophisticated nutrient management
and decision support platform
• Key backers
– The fertiliser industry (Fertiliser Association of New Zealand)
– Government (Ministry of Primary Industries)
– Science (AgResearch)
OVERSEER® is based on real data
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“Data based” model (empirical)
Based on real data on nutrient flows on farms
Designed for New Zealand conditions and farm systems
Long-term equilibrium model – outputs reflect average
processes over time
• Continually evolving and improving
OVERSEER® 6 – The latest version
• Improvements based on user feedback
• Better science and data
• Handles farming systems better
– Single enterprise model (integrates pastoral, cropping and irrigated
farming systems)
– Better options for managing supplements
– Handles differential grazing
– Extended effluent management options
• Modern software
What does OVERSEER® do?
OVERSEER® estimates the flow
and fate of nutrients
• Models the flow of nutrients (N,P, K, S, Ca, Mg, Na) on a range
of farming systems (for each block and the whole farm)
• Estimates diffuse losses to the environment
– Amount of nitrogen leaching from the root zone
– Risk of phosphorus loss
– Amount of greenhouse gas emissions
Nutrient outputs (N and P)
Leaching and run off (from root zone / farm boundary)
OVERSEER® Nutrient Budget
An irrigated dairy farm with shallow stony soils
OVERSEER® Nutrient Budget
A semi-intensive hill country breeding / finishing
sheep and beef farm
OVERSEER® Nutrient Budget
A dryland wheat farm with silty clay loam, high
current Olsen P levels, straw baled and removed,
stubble residues burnt
OVERSEER® Nutrient Budget
A block of potatoes with silt loam over a stony
matrix at 0.1 – 0.2m, high Olsen P (45) and
high fertiliser P inputs
OVERSEER® is output focused
• Input versus output management of diffuse agricultural
discharges for water quality
Inputs
Fertiliser
Feed
Stocking rate
Outputs
Nitrate and phosphate
OVERSEER® is practical
and cost effective
• Can estimate diffuse discharges by measurement (lysimeters)
– Hundreds of thousands of dollars per farm
• Can estimate diffuse discharges by modeling (OVERSEER®)
– At a marginal cost
How well does OVERSEER® work?
Accuracy of OVERSEER®
• Often quoted that “OVERSEER® is +/- 20% or 30% accurate”
– What does this really mean?
• Accuracy is best assessed by comparing model output with
real ‘unseen’ observations → validation
Validation N leaching from
farmlet comparisons
• Farmlets centred around key centres (Waikato, Manawatu and
Southland)
Overseer estimated (kg N/ha)
140
120
1:1 line
100
80
60
40
20
0
0
20
40
60
80
100
Measured N leaching (kg N/ha)
120
140
Background P Risk
P losses
y = 0.99x + 0.2
R2 = 0.96
Annual P Loss (kg P/ha/yr)
Accuracy over time (8 years)
OVERSEER® is valid
• OVERSEER® provides valid estimates of average N loss over
time Provided:
– Inputted data are accurate
– Default values used are reasonable (e.g. average rainfall data for the
sub-region)
– Standard best practice is followed on the farm
– Used by a properly qualified person
How is OVERSEER® used?
Uses of OVERSEER®
• Calculate maintenance fertiliser and lime requirements
• Develop Nutrient Management Plans
– Includes environmental risk and mitigation options
• Calculate effects of farm management scenarios on N, P and
GHG discharge / emissions
• Benchmarking and reporting tool
• Contribute information to catchment modeling (e.g. CLUES)
• For consenting / regulatory purposes
OVERSEER® use as a nutrient
management tool is growing rapidly
• 80% of all dairy farms have a nutrient budget
– 56% have nutrient management plans
• About 700 sheep and beef farms have a nutrient budget
– About 300 have nutrient management plans
• About 46% of all nutrients applied to land managed through
nutrient management plans
• About 950,000 ha of intensively farmed land with a nutrient
management plan
OVERSEER® and regulation
Drivers of regulatory use
• Intense interest in managing water quality
– NPS-FW, LaWF, public scrutiny
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Managing agricultural growth within limits a key issue
Best tool available
Allows output, effects based approaches
Not surprisingly, growing regional council interest in the tool
Where is OVERSEER® being used for
regulation?
Horizons – Used as a reporting
tool to meet specified N leaching
maximums set by LUC for
sensitive catchments
Waikato Regional Council – Used to set N
limits and allocate NDAs for Lake Taupo
catchment
Bay of Plenty – Used to set benchmarks and
track farm level changes (N and P) for Rotorua
Lakes
ECAN – Industry called upon to set discharge
limits and OVERSEER® would be the tool of
choice to monitor against these limits
Otago Regional Council – Proposed to use to
estimate N discharges against N discharge
limits (10, 20 or 30 kg N/ha/yr)
Environment Southland – Used to develop nutrient
management plans to enhance GMP uptake as a
requirement for a new dairy farm conversion
Next steps
What is needed for OVERSEER® to be
a robust regulatory tool?
• Standards, rules and protocols (national guidance)
• Ongoing funding for model maintenance and development
(core and supplementary)
• More data for calibration and validation for more farm
systems
• Enhanced delivery model
• Improved stakeholder involvement
• Certification of nutrient management advisors
• Third party audit of input parameters
Certification
NMA Advisory Group
Oversees the certification programme
Admin’
support
Admin’ and
records
manageme
nt
Applicant
recommendations
Appeals process
Advises
Board of
Directors
NMA Standard Setting
Group
Defines the initial
standards of competence
for knowledge and skills
NMA Certification Panel or
Education Committee
Reviews certification issues,
ensures benchmarks are met
Potential OVERSEER® governance
and delivery structure
Science and
Expert User
Panels
Owners: Ministry of
Primary Industries,
AgResearch and the
Fertiliser Association
of New Zealand
Stakeholder
Advisory
Group 1
Contractual Agreements
Providers
1. HortNZ, FAR, Federated Farmers, Beef + Lamb, Deer Industry, Irrigation New Zealand, New
Zealand Pork, DairyNZ, regional councils, etc.
Thank you