Areas of interest:
- Pasture plant physiological ecology
- Pasture production and management
- Grazing management
- Dairy farm systems analysis and development
- Farm systems modelling.
- Pasture persistence
- DairyNZ Forage Value index: Supporting Science (species interactions, genetic gain)
- Pastoral 21 programme: Objective 3, Next Generation Dairy Systems Canterbury
Helped develop the DairyNZ Forage Value index tool, now available to farmers (at www.dairynz.co.nz) as a source of independent, economically-based information on ryegrass cultivar performance in NZ dairy systems.
Leader of the Pastoral 21 dairy systems objective, Canterbury, investigating management strategies for reducing total N leaching from dairy systems while maintaining or increasing productivity,
In Australia, led projects that delivered to industry:
- 'DairyMod', a computer simulation model of the dairy grazing system including water and nutrient cycles, used in the design of new research projects and by at least one commercial dairy farm management consultancy business for analysing the risk of different business management strategies
- Evidence that the potential productivity of perennial ryegrass-based dairy systems is greater than previously assumed, and the management practices and decision rules that need to be implemented to unlock that potential
- Clear messages regarding the selection, management and economic value of complementary forages systems in non-irrigated dairy regions.
- information to assist sheep and beef farmers to understand the benefits and drawbacks of different grazing methods, within the context of their whole farm system, and optimise their choice of grazing method in the context of farming goals and available farm resources.
In recent years, science activities have including a large focus on the development of bio-modelling tools and implementation of approaches for analysing the impacts of change in the strategic management policies of dairy farms on production, profit, and environmental outcomes. These tools/approaches have been applied to non-irrigated and irrigated dairy systems in southern Australia, and irrigated dairy systems in the South Island of New Zealand. They have substantially assisted the design and interpretation of system-scale experiments which have tested propositions regarding the benefits of manipulating the pasture species used, incorporating forage crops in the farm feed base, the effects of climate change, and the adaption of farming systems to reduce environmental impacts.
Earlier scientific achievements centred around understanding the ecology, population biology, and growth dynamics of pasture species, and their implications for grazing management; determining the physiological capacity for resource capture and translocation within pasture plants, and hence our ability to explain and predict plant responses to variation in the availability of growth resources; and applying this information to plant breeding objectives and germplasm evaluation, mostly in white clover.
Invited keynote speaker at International Grassland Congress (1993, 2005, 2013); Asian-Australasian Animal Production joint conference (2000); Crop Science Society of America annual meeting (2005); Argentinian Congress of Animal Production (2006); American Dairy Science Association (2007).
Supervised 12 PhD students (9 as chief supervisor) and 4 Masters by Research students (3 as chief supervisor) to completion.
Career output summary:
Refereed papers/reviews//book chapters:
Associate Editor, Grass and Forage Science (Blackwell Scientific); Associate Editor, Animal Production Science (CSIRO Publishing)
Member of New Zealand Grassland Association; British Grassland Society; Grassland Society of Southern Australia; Crop Science Society of America.
Member, Science Advisory Panel, Pastoral Genomics
Chair, Forage Value Steering Group (DairyNZ – New Zealand Plant Breeders Research Association)
Chair Forage Value Working Group (DairyNZ – New Zealand Plant Breeders Research Association)
Chair, Endophyte Technical Committee (joint industry-plant breeding co-ordination of endophyte evaluation procedures and information on endophyte efficacy).