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Background. Deteriorating water quality is a major threat to the waterways and bays of PPWP In 2004, only 25% of the waterways were in good or very good condition.50% of the PPWP regions is utilised for agr. pursuits (4,500 enterprises, annual production value $1 billion ).Agricultural la
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1. Evaluating the effectiveness of agricultural management practices to reduce nutrient loads from farms in PPWP Port Phillip and Westernport Catchment
2. Background Deteriorating water quality is a major threat to the waterways and bays of PPWP
In 2004, only 25% of the waterways were in good or very good condition.
50% of the PPWP regions is utilised for agr. pursuits (4,500 enterprises, annual production value $1 billion ).
Agricultural land is a significant contributor of nutrients (nitrogen and phosphorus).
3. What we ALREADY know... Clear link between the way agricultural land is managed and nutrient export.
Nutrient export from some agr. pursuits is controlled through licensing, reducing nutrients from majority of land uses relies on BMP’s.
Appropriate management of agr. land through the adoption of BMP can reduce nutrient exports and minimise water quality impacts.
Ability to reduce nutrient exports varies from farm to farm, catchment to catchment, industry to industry.
Practices that are successful in one area may not be suitable for all farms or land uses in catchment.
4. What we DON’T know...
5. What we NEED to know...
6. Project overview: Aim: To evaluate the effectiveness of agricultural BMP’s to reduce nutrient (TN and TP) exports from farms to waterways.
Two year project (June 2005- June 2007).
Partnership between DPI CAS and PIRVic Soil and Water Platform
Working group (9 members-inter-agency, technical expertise)
7. Working Group:
8. Land uses Investigated Project focuses on catchments and land uses that have been
identified as key sources of Nitrogen and Phosphorus in PPWP:
Dairy (Westernport)
Beef (Westernport)
Strawberry (representative of annual horticulture) (PP- Yarra)
9. Methodology 2 sections:
Bayesian Network Model development
Model application and demonstration (Scenario testing)
10. Part 1: Bayesian Network Models Development of 5 Bayesian Networks Models (TN and TP):
2 x Dairy
1 x Beef
2 x Annual horticulture (Strawberry)
Bayesian Network Models:
Describe cause and effect of management decisions on outcomes
Incorporate qualitative and quantitative information from all levels (farmers, industry, agency, scientists etc..) thereby reducing uncertainty.
Calculates consequence of agri. management practices by determining probability (%) of small, medium and large TP/TN load under different management scenarios and landscape characteristics
Limitations (What it can’t do!):
Give absolute numbers on nutrient export loads (ie. t/ha/yr). This is presented in probability (%).
Model at farm scale (not catchment). Scenario are used to test and demonstrate wider industry/catchment /regional application.
12. Example: Diffuse TP load (Dairy)
13. Model Applications Scenario Testing:
To demonstrate how changes in climate, landscape factors (eg. soil
types, rainfall, slope) and management practices (eg. effluent and
fertiliser management) can influence TN and TP export.
16. Where to from here? Assessment of results
What do these results mean for:
Farmers?
Land use and agri industry (ie. dairy)?
Management of agricultural land in catchment?
Broader application/PPWP/BBW Strategy?
Future Implementation mechanisms?
Knowledge and research gaps (R and D requirements)?
Final Project report due: June 2007.
17. Thank You
Anja George
Department of Primary Industries
Woori Yallock
Ph: (03) 5954 4001
anja.george@dpi.vic.gov.au