DAV 413
(Incorporating DAV 400 and ARC-C19804739)
Final Report
October 2001
Report prepared by
Dr Richard Eckard ILFR, The University of Melbourne and NRE Ellinbank,
www.nitrogen.unimelb.edu.au
Contents
1. Summary 4
2. Project Team 7
3. Introduction and Background 8
4. Principal Aims 10
5. Project Details 10
6. Acknowledgments 11
7. Report of Results against Aims 12
7.1 To formulate practical management guidelines to minimise nitrogen losses while maintaining productivity in dairy pastures in south eastern Australia 12
7.1.1 Critical Review 12
7.1.2. Decision Support System (DSS) development 12
7.1.3 Best Management Practices For Flood Irrigated Systems 14
7.1.4 Strategic application of N in western Victoria (DAV400) 14
7.2 To evaluate a range of existing simulation models for their applicability to N cycling in grazed dairy pasture systems in south eastern Australia 14
7.2.1 Nitrogen cycling - Experiment at Ellinbank 14
7.2.2 Nitrogen cycling - Model evaluation 15
7.3. Through an annual workshop with the collaborators identify critical information gaps required to deliver on the objectives 16
7.4 Best Management Practices 17
8. Industry Implications 18
9. Future Research/Recommendations 19
10. Intellectual Property 20
11. Communication and Publications 20
12. Evaluation 35
Appendix I – Nitrogen Decision Support Tables – Eckard, McKenzie and Mundy 37
Appendix II – Gaseous N losses Paper – Eckard et al. 40
Appendix III – Nitrate leaching - Eckard et al. 59
Appendix IV – Nitrogen Balances - Eckard et al. 70
Appendix V – Northern irrigation report - Mundy 77
Appendix V.a. – NFixCycle evaluation – Mundy 84
Appendix V.b. – Nutriace evaluation – Mundy 91
Appendix V.c – N and P movemement in soil – Mundy and Bethune. 106
Appendix VI - Extract of DairyMod Report – Chapman et al. 115
Appendix VII – Model evaluation – Eckard 121
NfixCycle Model 121
AgResearch N Model 124
Appendix VIII - Summary of DAV400 Final Report - McKenzie 125
Appendix IX - Nitrate Leaching in Western Victoria - McCaskill 128
Appendix X - Gopher probe calibration - Smith 134
1. Summary
Nitrogen (N) fertiliser use on dairy pastures in south eastern Australia has increased exponentially over the past 15 years, with over 60% of dairy farmers topdressing pasture with N fertiliser at least once per year. This increase in N fertiliser use is largely driven by increasing stocking rates, which has served to highlight the limitations of clover N2-fixation in providing sufficient N for maximum grass production, especially during the cooler months of the year.
In response to a series of strategic planning workshops, a statewide N research project was initiated on the 1st July entitled “Best Management Practices for Nitrogen in Intensive Pasture Systems”. This project linked existing research in Western Victoria (DAV400) and NRE Hamilton, with new projects located at NRE Kyabram, NRE Ellinbank and ILFR, the University of Melbourne. The research team were jointly from NRE and the University of Melbourne, while project purchasers were NRE (and the Agricultural Food Initiative), the University of Melbourne and an Australian Research Council SPIRT grant, the Dairy Research and Development Corporation (including WestVic Dairy), Incitec Ltd and Pivot Ltd.
The statewide N project aimed to formulate practical management guidelines to minimise nitrogen losses while maintaining productivity in dairy pastures in south eastern Australia; evaluate a range of existing simulation models for their applicability to N cycling in grazed dairy pasture systems in south eastern Australia, and identify critical gaps in information.
In order to formulate practical management guidelines critical reviews of all nitrogen research conducted in Victoria relevant to intensive dairy pasture systems were conducted for both flood irrigated and dryland systems. These reviews summarised current and past research on nitrogen for intensive pastures, identifying critical gaps in information.
The data from the critical reviews, current research and relevant international experience were used to formulate practical management guidelines for the effective and sustainable use of nitrogen fertiliser on dairy pasture. These guidelines and best management practices are now available in a booklet (How to use N confidently), brochures printed by Incitec Ltd and Pivot Ltd and from the project web site (www.nitrogen.landfood.unimelb.edu.au).
From the reviews and research, lookup tables of likely responses to N fertiliser were compiled for each dairying region of Victoria. These lookup tables formed the basis of an MS Excel and a web-based Decision Support System (DSS) now available from the project web site and from www.target10.com.
The project also evaluated a range of N cycling models for their applicability to intensive dairying in Victoria. Of the models evaluated DairyMod was the most promising dynamic model, with the AgResearch DAMN model also holding promise as an annual time step model. The model evaluations are detailed in the report.
The critical review of literature revealed that there were no complete data sets of N losses from grazed dairy pastures systems in south eastern Australia. To evaluate N cycling models adequately the research team, therefore, required a local data set from a closed system quantifying the losses and transfers of N in a grazed dairy pasture system.
New research conducted within the statewide experiment was divided into two main components:
1. A research project was initiated at Ellinbank investigating and quantifying the losses and transfers of N in intensive dairy pastures.
2. A stocking rate by N rate grazing experiment at Demo Dairy, Terang, investigated the strategic application of nitrogen on grazed perennial ryegrass/clover pastures in western Victoria (DAV400). To value add to this experiment, an additional experiment investigated nitrate leaching losses within this grazing experiment.
The findings from these research projects are detailed in the report.
From the critical reviews and new research, the project team were able to compile a list of Best Management Practices for N fertiliser management on intensive pastures. These are detailed in section 7.4 of the report.
The final aim of the project was to identify critical gaps in information requiring further research and development, with the following areas identified:
· Greenhouse gas emissions: Quantifying nitrous oxide emissions from both dryland and particularly flood irrigated pasture systems. The potential for management manipulation of nitrous oxide to di-nitrogen ratios. Nitrous oxide emissions from nitrification as opposed to denitrification
· Environmental Impact: Reducing the spatial distribution and quantity of urinary N deposition through dietary modification. Quantifying organic N and urea N leaching.
· N Models: Refinement and ground-truthing of identified N cycling models. Model evaluation using the Demo Dairy, Terang site data.
· Best Management Practices: Evaluation of the catchment impact of N best management practices. Incorporation of N Best Management Practices into a whole farm Environmental Management System (EMS).
· Decision Support System: Expand the current decision support system to include environmental impacts of N fertiliser use. Expand the current decision support system to include other dairying regions in south eastern Australia.
Further details on the above are contained in the relevant sections of the report.
This project represents a major step forward in our understanding of environmental and economic best management practice for N fertiliser use on intensive pastures in Victoria. The outputs from this project have provided the Victorian Dairy Industry with all the N fertiliser management guidelines and decision support tools they require to implement and demonstrate current world best practice for the management of N fertiliser in intensive grazing systems.
2. Project Team
The Department of Natural Resources and Environment
AV Ellinbank: Dr Richard Eckard (Project Coordinator), Paul Durling
Warrnambool: Dr Frank McKenzie (Regional Coordinator), Michele Ryan, Stewart Burch
AV Hamilton: Dr Malcolm McCaskill (Regional Coordinator), Jean Lamb
Kyabram Dairy Centre, ISIA: Geoff Mundy (Regional Coordinator)
The University of Melbourne
Dr Richard Eckard (Project Coordinator), Prof. David Chapman, Prof. Robert White, Dr Robert Edis, Dr Helen Suter, Dr Deli Chen, Andrew Smith.
Collaborators
NRE Ellinbank: Dr Chris Grainger (Director), Murray Hannah (biometrics)
CAS/Target 10: Geoff Thomas (DSS development), Greg O’Brien (Pasture Management Course), John Bowman, Colin Waters, Frank Mickan (Soils and Fertiliser Course)
CSIRO, Plant Industry: Dr Richard Simpson (Nutriace), Dr Tom Denmead (Micrometeorological Methodology)
IMJ Consultants Pty. Ltd: Dr Ian Johnson (DairyMod)
DPIF and TIAR, Tasmania: Peter Gillard (DSS), Dr Ali Salardini
AgResearch, New Zealand: Drs Jim Crush and Stewart Ledgard (DAMN Model)
IGER, UK: Drs David Scholefield and Lorna Brown
FRC, Denmark: Dr Nick Hutchins (FASSET Model)
3. Introduction and Background
Nitrogen (N) fertiliser use on dairy pastures in south eastern Australia has increased exponentially over the past 15 years, with over 60% of dairy farmers topdressing pasture with N fertiliser at least once per year (Eckard et al. 1997; Eckard and Franks 1998; Eckard et al. 2000). This increase in N fertiliser use is largely driven by increasing stocking rates, which has served to highlight the limitations of clover N2-fixation in providing sufficient N for maximum grass production, especially during the cooler months of the year (Ball and Ryden 1984; Eckard and Franks 1998).
Figure 1. Nitrogen fertiliser sales to all pastoral farmers in Victoria (Eckard et al. 1997).
In 1996, Agriculture Victoria commissioned a review of its 5-year Dairy Industry Program. The review included workshops at Knoxfield on the 29th March 1996, and Ballarat on the 5th and 6th of June 1996. This review included participation from over 25 Industry representatives drawn from MRDID, ADPF, Murray Goulburn, Bonlac Foods Ltd, UDV, NHIA, VDIA, DRDC and regional boards. Government agencies included 45 representatives from Agriculture Victoria, CAS (Target 10), the University of Melbourne and VCAH, Latrobe University, CSIRO, New South Wales Department of Agriculture, the Tasmanian Institute of Agricultural Research and the South Australian Research and Development Institute. This planning forum broadly identified priorities for future research, including placing a high priority on nitrogen fertiliser research in the dairy industry of South Eastern Australia.
Based on the above mandate, and a previous nitrogen workshop held Agriculture Victoria Ellinbank (AVE) on the 17th October 1995, a further workshop was held at AVE, on the 7th November 1996, in order to refine the priorities for future nitrogen research. Representatives attended this workshop from DNRE (Agriculture Victoria and Target 10), DRDC, AgResearch (NZ), TIAR Tasmania, WA Department of Agriculture, Incitec Ltd, Pivot Ltd, HiFert, CSIRO, CALP board, local farmers and the University of Melbourne.
This workshop identified two main outputs that were required from a N fertiliser research program:
1. To develop a decision support system (DSS) that optimises profitability of N fertiliser use while meeting off-site environmental impact standards, and
2. To determine the environmental impact of N fertiliser use in dairy production systems.
In late 1996, The University of Melbourne and the Victorian Department of Natural Resources and Environment (NRE) entered into discussions on the prospects for establishing a collaborative research program to develop best management practices for the use of nitrogen (N) fertiliser on dairy farms in south eastern Australia. Subsequent to the last workshop on 7th November 1996, Agriculture Victoria and the University of Melbourne proposed the appointment of a Senior Research Fellow to lead a research program in delivering on the above outputs. Resulting from this Dr Richard Eckard was appointed to the Animal Production Department of the Institute for Land and Food Resources, the University of Melbourne, but located at the NRE Ellinbank. This appointment was jointly funded by NRE and the University of Melbourne, in keeping with the new research ‘provider’ strategic alliance concept.
In anticipation of the appointment of the Senior Research Fellow, a research proposal was submitted to the Australian Research Council (ARC) by Prof Dave Chapman and Dr Richard Eckard, University of Melbourne. This proposal aimed to review all N fertiliser research in south eastern Australia, to initiate research determining the environmental impact of N fertiliser use in dairy production systems and to initiate the delivery of a DSS for N fertiliser use. This application included funding for the development of a software decision support system. Funding for this project was received in March 1998, totalling $205 K over three years.
Concurrent with the above process was the commissioning of the Victorian ‘large projects’ by the ‘purchaser’ alliance. Throughout the development of the Soil, Water and Nutrients project the above nitrogen fertiliser sub-project continued to receive priority attention for research. The result was that the N project was identified for ‘fast-tracking’ to ensure commencement by the 1st July 1998, incorporating all N fertiliser research in the Victorian grazing industries currently funded by the collective purchasers.
Concurrent with the above process relationships were developed between the various researchers working on N fertiliser in South Eastern Australia (Dr Richard Eckard – TIAR, Tasmania and later NRE/ILFR, Dr Frank McKenzie – NRE Western Victoria, Dr Malcolm McCaskill – NRE Hamilton and Geoff Mundy – NRE Kyabram), with a view to coordinating activities and working towards a single, unified approach. Resulting from these discussions a 3 year funding submission was put to the purchaser alliance and the research team was successful in securing funding from the Victorian state government ($522 K) and its Agricultural Food Initiative ($308 K), the Dairy Research and Development Corporation ($403 K) and the University of Melbourne ($210 K), to add to the existing Australian Research Council grant ($205 K).
An additional ‘in-kind’ commitment was secured from both Incitec Ltd (estimated value $20K) and Pivot Ltd (estimated value $20K) to provide all chemical analyses their laboratories can provide, as well as all the fertiliser required by the statewide N project.
This report represents the final report for the coordinated statewide nitrogen sub-project, commissioned by NRE and DRDC in July 1998, as part of the Soil, Water and Nutrients Large Project.
4. Principal Aims
1. To formulate practical management guidelines to minimise nitrogen losses while maintaining productivity in dairy pastures in south eastern Australia.
- To evaluate a range of existing simulation models for their applicability to N cycling in grazed dairy pasture systems in south eastern Australia, and
- From #1 and #2, above, to identify critical gaps in information essential for refining aims #1 and #2.
5. Project Details
Figure 2 provides an organisational chart of the structure of the project. A detailed description of the methods and resources used at each location is provided in the separate sub-project reports in this document.