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Technology options for improving water quality while increasing land productivity
Compiled by: Liz Wedderburn (AgResearch) , Clive Howard-Williams (NIWA), Peter Millard (Landcare Research) Together with input from: Scion Research, Plant and Food, GNS Science, ESR, University of Waikato, Lincoln Agritech, Massey University, Lincoln University, Aqualinc Research, Dairy New Zealand
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Presentation format Key Messages Context (Definitions and variability)
Technologies, impacts and costs Enabling tools Potential future technologies Case studies Adoption
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Take home messages There is no silver bullet but:
Technologies are currently available for a variety of circumstances from the paddock to catchment scale and future technologies are under development. Effectively adopted technologies should be sufficient in most places (to meet desired standards and/or create headroom). Land use change and/or restoratory approaches will be required in some vulnerable and already significantly impacted catchments and costs are likely to be significant in order to meet community outcomes. Uptake of effective technology is dependent on the willingness and motivation of farmers at the source end, their skill base, effective adoption pathways and community understanding at the receptor end. Science is also informing community processes at the catchment scale, and developing relevant networks to enable a cross sectoral/policy/science approach that will enable adoption.
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Context definitions What is Water Quality?
A variable, often defined by communities, but good quality may be water that is safely drinkable, swimmable and fishable, supports cultural values and healthy ecosystems. The three main issues affecting water quality in rural settings are: Suspended sediments: that smother the beds of rivers and estuaries Nutrients (nitrogen, phosphorus): that encourage excess plant growth, algal blooms Faecal microbes: that affect human, and often animal, health. 2. What is productivity? “measure of the efficiency of production, defined as the ratio of output per unit of total input” Increased volume and or increased value. 3. What is Technology? An instrument (e.g. a sensor) A system (e.g. climate forecasting) A farm management practice (e.g. time of application of N fertiliser) A catchment intervention (e.g. Riparian margins) Infrastructure (e.g. Irrigation scheme) Included also are enablers of technologies such as decision support tools e.g. Crop calculator and adoption processes.
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Co-benefits Increasing efficiency in animal performance Reducing GHG Improving biodiversity on land and in water Improving recreation use and landscape value Integrating technologies that meet multiple outcomes has huge potential but interactions mean that the result may not be additive. We can check for pollution swapping (e.g. decrease N to water, increase GHG), through application of tools such as Life Cycle Analysis.
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Variability through space and time Consequences for what and where
Understanding and managing variability, and uncertainty underpins our science and informs community decision making in an uncertain environment. NZ’s complex landscapes and geology impart significant climatic, water resource and soil variability at regional and national scale. Climate change will add further variability Overlying this is variability that exists in farmer behaviour.
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Variability in space Large and small scale variability in soils, vegetation, climate, water yield, water availability, etc. will affect ability to farm and maintain water quality. Runoff (mm/year) Low flow (L/s/km2)
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Variability and land use types
Farm and catchment losses ( present) None Sheep Mixed Deer Dairy Arable Variability and land use types Different land use types result in different contaminant losses adding further spatial variability The wide range of losses within a land use is due to: climate soil type topography management Infers much gain can be made
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Variability in dairy production by region 2011-12
Production (Million kg) Export Revenue $7.44/kg Northland 125 929 Waikato 509 3,789 Bay of Plenty 68 505 Taranaki 173 1,290 Lower North Island 152 1,129 North Island 1,027 7,642 West Coast - Tasman 50 369 Marlborough - Canterbury 328 2,439 Otago - Southland 280 2,085 South Island 658 4,893 TOTAL 1,685 12,535 The average annual increase in milksolids production per herd since the season has been 4,721 kilograms or a least squares annual growth rate of 4.5%. Contributing to this has been: • More hectares – annual growth in milking area of 3.8 ha (+3.1% per year); • More cows – annual growth of 12.8 cows per herd (+3.9% per year); • Higher stocking rate – annual growth of 0.02 cows per ha (+0.8% per year); • More milksolids per cow – annual growth of 1.7 kg (+0.5% per year); and • More milksolids per hectare – annual growth of 11.8 kg (+1.4% per year). In summary, the annual growth in cows per farm (+3.9%) has been slightly faster than the growth in milking hectares per farm (+3.1%), and therefore stocking rate has increased slightly (+0.8%) over the last 10 years. This increase in stocking rate coupled with the small growth in milksolids per cow (+0.5%) resulted in an annual increase in milksolids per milking hectare of 1.4%
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Variability in time (Waikakahi Catchment, Canterbury)
Lag in response of suspended sediments (SS) and total phosphorus (TP) to improved stock exclusion and reduced pond discharge in 1996
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Variability in performance
Farm nutrient efficiency and N losses to waterways Room for improvement to low leaching levels Waikato
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Variability in Farmer behaviour
How farmers approach work is likely to depend on their personal preferences and likely to change through life
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Process understanding to target technologies
Science has provided a considerable background understanding of sources, pathways and sinks of contaminants at farm and catchment scale This along with understanding farm system behaviour has enabled identification of efficiency gains and system fit of technologies Some examples:
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Science process understanding farm scale urine patch
Drainage out of root zone (mm/month)
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Science developed Technologies-farm scale
Target: Reducing Nitrogen leaching in grazed pastures Now 3-5yrs >5yrs Now 3-5yrs >5yrs Now 3-5yrs >5yrs High cost Winter housing & manure management Tactical Restricted grazing Strategic Supplementary feeding, low N diet Improve irrigation, farming practice DCD North Island Soil processes, new products & formulations (commercial) Constructed and managed wetlands, denitrification systems Change Animal Type Transformational Greater root activity Duration control grazing Med cost Ryegrass N use efficiency DCD South Island Diuretic supplementation or N modifier High sugar grass Lipids or ionophores Environmental forecasting Match land to agricultural use High tannins Low N pasture BioChar Gain in nutrient efficiencies by nutrient management, farm systems approach, overseer, precision agriculture Strategic C addition Inhibitory root exudates Low cost Targeted mitigation high N,P areas Optimise timing of pasture grazing / feed to lower N in diet Optimal fertiliser management Effluent mgmt. Low Impact (0-10%) Medium Impact (10-30%) High Impact (>30%)
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Partnership with Sectors
Technology pipeline Partnership with Sectors Proof of concept Plot/paddock testing On-farm testing System evaluation ACTION Reducing animal carriage rates Managing Critical Source Areas Split grass/clover Winter forage P sorbents Fertiliser N efficiency Attenuation systems Restricted grazing Portable standoff pads BMP toolbox Nitrification Inhibitors Applied end of development pipe-line. I.e. no underpinning research which is coming from other programmes such as SWQ and Taupo. Increased interaction with extension agencies (particularly Dexcel, but also MWNZ) at right hand side of pipeline. Diuretics Precision N fertiliser placement Constructed wetlands Bottom-of-catchment wetlands P sorbers for wetlands Grassed swales Legend: Microbes, phosphorus, nitrogen, combination
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Southland dairy farm case study
The effects of cumulative management changes on N leaching and farm profit: Southland dairy farm case study Progressive implementation of measures: Improved nutrient & effluent management; higher per cow + N inhibitor (DCD) + Herd Shelters + wetlands
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Reducing P losses from southern dairy farms:
Large reductions possible for relatively minor cost nil -1% +1% ? Change in profit Proposed target Natural baseline
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Improve Production Efficiency: e.g. N
Improved production efficiency of N can be achieved with higher genetic gain animals, better pastures and efficient use of artificial N, optimizing stocking rates and use of animal shelter e.g.: Scenario Profit ($/ha) Production (kg MS/ha N loss (kg N/ha) Baseline Canterbury dairy farm (modelled) 2000 1500 40 Current breeding worth & better N management 2150 1600 35 High breeding worth, low stocking rate & better N management 2450 1750 20 High breeding worth, high stocking rate & better N management 2500
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Improve Production Efficiency: e.g. P
Improved production efficiency of P can be achieved with: more genetically efficient plants and animals (inc. transgenic), manipulation of systems spatially and temporally e.g.: Have 10-15% of dairy farm occupied by: low P runoff areas near streams in ryegrass high P runoff areas in clover Modelling shows - profitability up $40-100/ha (10% more MS) - P losses to stream down by 40% Timeline: improved system within 3 years. c. 40% decrease
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Mitigation Technologies: P
23/05/10 Strategy Effectiveness (%) Cost ($/kg P conserved) Effluent pond storage / low rate application Source management 7-10 20-25 Optimum soil test P 15-45 0-6 Low water soluble P 5-48 1-9 Restricted grazing 30-50 10-100 Tile drain In-field amendment 15-50 41-54 Aluminium sulphate to pasture / cropland 10-40 Buffer strips Edge of field 0-10 >200 Stream fencing 14-50 19-27 Sorbents in and near streams 30-80 59-91 Irrigation water use and recycling 10-80 -80 - >400 Natural and constructed wetlands -3-20 Mean cost-benefit decreases away from source (or as scale inc.)
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Science developed technologies - Catchment scale
Technology/model (example) +ve Impact on water quality Relative Cost Environmental forecasting, detailed time and space (EcoConnect) High Low Critical source area mapping and delineation Catchment-wide riparian management Medium Storm-flow mitigation Riparian management guidelines Decision support systems: EFSAP, NZ Farm (economic modelling), LUMASS (land optimisation tool) Improved waste water treatment technologies Constructed wetlands and managed natural wetlands Microbial source tracking
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Catchment –scale: Downstream technologies in receiving waters – Advantages may be rapid improvement in water quality but major risks are on-going operational costs Intervention Sediment capping Lake Okaro (30 ha) modified zeolite application c. $75,000 p.a. over 3 years Phosphorus inactivation Lake Rotorua alum dosing $1M p.a. Dredging Expensive although costs will vary considerably depending on circumstances Oxygenation/destratification Destratification trial in lake Rotoehu (790 ha): $524,000 Hypolimnetic withdrawal Limited application so far in NZ but proven to be “low cost” in Europe and USA. Weed harvesting Hornwort harvesting in Lake Rotoehu (790 ha): $52,800 p.a. $22/kg N and $165/kg P Diversions Ohau Channel wall in Lake Rotoiti (124 ha): $10 million
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Enabling tools Underpinned by 30 years of science
A farm-level nutrient management Decision Support System, freely available Enables nutrient budgets to be constructed for many farm enterprises Allows a wide range of management options and mitigation practices to be assessed Enables flexibility in meeting water quality targets The essential starting point for farm nutrient management plans Links with other enabling tools, e.g. Farmax – aids farm system design CLUES – scales up to the catchment Widely used throughout New Zealand by advisors, farmers, policy-makers Nutrient budget Nutrient management plan Whole farm plan Overseer
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Testing farm feasibility under future scenarios
Dairy in the Manawatu out to 2020. Milk solids from 950 to 1230 /ha. Very much business as usual N leaching losses also increase . Will this be permitted ? Large absolute differences in N loss between sheep and beef and dairy 4-8 fold, in addition to trajectories .
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Enabling tools: CLUES (Catchment Land Use & Environmental Sustainability)
A nationally applicable, regional and catchment relevant GIS Decision Support Tool that uses OVERSEER and assesses links between rural land-use, land use change, and catchment-level effects on water quality allow users to make predictions of the effects of land use change on water quality & indicative socio-economics Land Use Water Quality N load Forest Dairy Other Pasture high low
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Enabling tools: Other models for Simulating scenarios for evaluating future impact
Models rely on good data Model User Use Scale SPASMO Research, Policy Soil, plant and atmosphere Farm NZ-Farm Economic modelling of policy impacts APSIM Research Agricultural Production systems simulator – farm management MyLAND Policy Economic and environment impacts of land use and land management Farm/catchment LUMASS Land Use management support system Farm/Catchment ROTAN Nitrogen transport model – GIS based Catchment NZEEM Erosion and sediment generation/transport NZ-SEDNET Sediment sources and transport – GIS based TOPNET Surface water flows – NZ national stream flow model MODFLOW/Mt3D Groundwater flow and transport model Aquifersim Groundwater flow model
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Next generation dairy farms: examples of regional responses
Waikato: Higher genetic merit cows, lower stocking rate, lower replacement rate, off-paddock periods in autumn/winter, reduced N fertiliser inputs and improved dietary balance Manawatu: Off-paddock cow housing systems to control grazing periods and a greater area of summer forage crop to meet feed shortages
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Next generation dairy farms: Examples of regional responses
Canterbury: Manipulation of crop management and animal diet, use of nitrification inhibitors Southland & Otago: Use of short rotation ryegrasses and whole crop cereal silage to increase feed availability, calving later, strategically grazing critical source areas to minimise farm runoff, using winter standoff pads or shelters
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Precision Farming Technology Options and Timeline
Tools developed that provide real-time monitoring to match the supply of water & nutrients with crop demand to maximise productivity: 2013 Crop calculators Water & irrigation management tools Variable rate irrigation 2016 New crop calculators developed (e.g. onions, kiwifruit) Advanced climate and weather forecasting Advanced irrigation scheduling
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Scenarios for change 3 types: 1. Headroom, local/catchment
Intensify current landuse, no mitigation Concentration Time With mitigation 1. Headroom, local/catchment Concentration target 2. Hold the line With on-farm mitigation Concentration Current concentration With catchment-wide mitigation Time Current concentration Concentration Time With mitigation 3. Claw back Concentration target
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Headroom - Hurunui: Estimates of N Losses to water
Reducing dairy losses: Low-hanging fruit: 10-20% Efficiency gains (animals & irrigation) Maximum technically possible: up to 50% Multiple measures; greater complexity; lower profit but more development
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Holding the line - Waiokura
2008: 50-60% riparian fencing and plants Regional council riparian policy Fewer pond discharges, more effluent irrigation Sediment and P down by 30-40% Faecal matter (E. coli) decreasing by 9% per year 2013: Continuation of trends of reduced sediment, less P, less faecal pollution, clearer water Mitigation not sufficient to hold the N line in this catchment due to intensification over the study period
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Clawback - Rotorua: Target: To return water quality to that of 1960s; Large N and P loss reduction is needed. In last 5-8 years a reduction of c. 15% in losses from dairy farms has occurred due to increased nutrient efficiency, BUT this is insufficient and there will be a need for a combination of: Increased N and P mitigations on farm, Catchment interventions and management (e.g. alum dosing), some diversions, etc. and Land use change e.g. dairy (23 farms) to sheep/beef or forestry
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Science informing Community Choices
Science centric management alone is not enough to address the issues Role of Science is to provide the science based evidence for technologies and behaviour change in an integrative way Science informed processes that allow: inclusive and integrated community conversations deliberation of the consequences of future land development while making transparent the trade offs across diverse outcomes
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Purple = over allocation Green = under allocation
A catchment will be allocated depending on the target set by the community Left-hand map is for N at a ‘Good-Fair’ (B-C) threshold for river algae growth, right-hand map is for N at ‘Fair-Poor’(C-D) threshold for river algae growth Purple = over allocation Green = under allocation
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Technologies on their own will not achieve the change
Klerkx et al (2012: 460) Technologies on their own will not achieve the change Must link to the motivation of the farmers/growers and place in a system context Build networks of farmers, educators, science and policy that link technologies and enabling tools to enable collective learning Under delivery of potential impacts of new technologies Calls from ministers for CRIs to participate more in extension Everyone is struggling to implement on the ground
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Take home messages There is no silver bullet but:
Technologies are currently available for a variety of circumstances from the paddock to catchment scale and future technologies are under development. Effectively adopted technologies should be sufficient in most places (to meet desired standards and/or create headroom). Land use change and/or restoratory approaches will be required in some vulnerable and already significantly impacted catchments and costs are likely to be significant in order to meet community outcomes. Uptake of effective technology is dependent on the willingness and motivation of farmers at the source end, their skill base, effective adoption pathways and community understanding at the receptor end. Science is also informing community processes at the catchment scale, and developing relevant networks to enable a cross sectoral/policy/science approach that will enable adoption.
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Acknowledgements The following scientists provided valuable background material and ideas for this presentation: AgResearch: Stewart Ledgard, Ross Monaghan, Mark Shepherd, Richard McDowell, Mike Freeman, Melissa Robson, Sue Peoples NIWA: Bob Wilcock, Bryce Cooper, Sandy Elliott Landcare Research: Peter Millard, Alison Collins, Suzi Greenhalgh Scion Research: Brian Richardson, Peter Clinton Plant and Food: Miriam Marshall, Derek Wilson, Brent Clothier GNS Science: Chris Daughney ESR: Murray Close University of Waikato: David Hamilton, Deniz Ozkundakci, Hannah Jones, Jonathan Abell, Dylan Clark and Chris McBride Lincoln Agritech: Hugh Canard, Peter Barrowclough Massey University: Mike Hedley Lincoln University : Leo Condron Aqualinc Research: John Bright Dairy New Zealand: Rick Pridmore, Bruce Thorrold
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