How to Manage Low Nitrogen Leachers in High Nitrogen Areas
Transcript of How to Manage Low Nitrogen Leachers in High Nitrogen Areas
2/12/2020
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How to Manage Low Nitrogen Leachers in High Nitrogen Areas
Presentation to the Waimakariri Zone Committee
13 August 2018
The Context
1996 2006
Over the past 20 years at least, we have seen significant land use change; land use
intensification; population growth – and groundwater and surface water quality decline
Source: Google Earth Pro
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What To Do About Low Nitrogen Leachers
What do you want?
♠ Address effects of land use on water
♣ A solution that works
♥ A solution that’s fair
♦ Balance different, sometimes
competing interests
⸙ Social license
What do we want?
Flexible land use within environmental
limits
Source: Environment Canterbury
What To Do About Low Nitrogen Leachers
For a start:
All sectors reduce losses
All sectors to implement GMP
Set reductions on a risk-based framework
Risk level correlates to regulation level (♥ ♦ ⸙)
Look at problem holistically (♠ ♣)
Set meaningful timelines (♣)
Low leachers = Low risk = Less regulation
High leachers = High risk = More regulation
It’s not just about Nitrogen
What Does This Look Like?
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What Does This Look Like?The Framework – From the River Up (♠ ♣ ♦ ♥)
1. What N concentrations can a waterbody’s freshwater systems
‘live’ with – this must enable ecosystem health and drinking
water
2. Use the desired N concentrations to set total N loads for a
waterbody. This must account for attenuation of the land in that
catchment
3. Calculate the total allowable loss from the land (per ha) by
dividing the total N load by the hectares in the catchment of that
waterbody
4. Use that total allowable loss per hectare as a ‘floor’. This floor
represents long term sustainable N losses from land use
Framework needs to look at
land as a sustainable
resource intrinsically
connected to the water.
Attenuation accounts for a
weighting on the land’s
productive potential,
susceptibility to leaching,
proximity to waterways,
ecosystem services
What Does This Look Like?The Framework – Implementation
STAGE ONE (♠ ♣ ♦)
All farms operating under
GMP within two years
STAGE TWO
(♥ ⸙ ♣)
Losses ≤ the N floor• Require a FEP
• No further reductions required
• Can increase up to the floor
• Focus on these low leachers
reducing other contaminants (esp.
through FEP)
Losses > the N floor• Require a nutrient budget
• Require a FEP
• Reduce losses 30% below GMP baseline levels
within 10 years.
• No further losses once farm is ≤ floor
• Then set appropriate goals for further reductions
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What Does This Look Like?Framework: In A Picture
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