Project Title: Sustainable rotations and cropping practices for the marginal cropping areas of NW NSW and SW Queensland

Project Supervisor: Dr R J Martin, (Dr. DM Freebairn)

Funding Body: GRDC

Admin Contact: Mr R Scott

Commencement Date: 07/95 Completion Date: 06/2005

1. Establish core sites, covering the range of soils and climate, to address strategic issues related to the most efficient management of soil physical, chemical and biological constraint under various continuous cropped and crop/pasture systems.
1. Address tactical issues related to the farming system through establishing an on-farm trial and demonstration network operated by growers and facilitated by project staff.
1. Improve the sustainablility of farming systems through action learning and value-adding to farmer group activities.
1. Develop models and decision support systems for assessment of tactical and strategic management options for crop/pasture systems in low rainfall cropping areas.

This project will develop sustainable rotations and cropping practices for the marginal cropping areas of NW NSW and SW Queensland. It is a project group incorporating DAN014, DAN 244, part of DAN245, PRP 497 and PRP 502. The "sub-program" is modelled on the innovative farming system approach adopted DAN 014. This approach consists of four key areas that will operate in an integrated fashion to deliver the needs of grain producers in the low rainfall environments of the northern cropping zone. The four key areas or modules are: Large scale crop/pasture system trials; On-farm demonstration/trial sites; Crop choice/check advisory packages; and Modelling.

This research proposal will result in the adoption of tillage and crop/pasture rotation practices in the low-rainfall part of the northern grains region (800 000ha) which are more profitable and sustainable. Without the project it is assumed that farmers will continue to focus on wheat production with conventional tillage techniques. During the period to maximum adoption (1998-2010), it is estimated that average wheat yields will decline from 1.4 t/ha to 1.0 t/ha. Average grain quality will decline from PH (3 years), through AH (4 years) to ASW (last 5 years). Without the project, the average gross margin will be $52.

Two scenarios for the project have been considered in the BCA. In scenario 1, it is assumed that farmers will adopt a 4 year pasture phase (1.6 dse) before commencing 2 cycles of a 4 year long-fallow wheat (1.9 t/ha) / faba bean (1.8 t/ha) / short-fallow wheat (1.5 t/ha). This scenario assumes that crop yields are maintained and protein levels remain above PH for the 12 year period. The average gross margin for this scenario is $111.

Scenario 2 assumes 3 cycles of the long-fallow wheat/faba bean/short-fallow wheat rotation. In the third cycle it is assumed that long-fallow wheat yields will fall to 1.85 t/ha, short-fallow wheat yields to 1.45 t/ha and that the final short-fallow crop would only make AH quality. This scenario give an average gross margin of $146.

Strategies will be developed to enable the most efficient management of water and nitrogen under various continuos cropped and crop/pasture systems under low-rainfall conditions. As on-going on-farm trial and demonstration network, operated by key grower groups, will be established to address seasonal tactical issues related to maximising profits whilst sustaining the farming system. The sustainability of farming systems will be improved through action learning and value-adding to a wider range of farmer group and agribusiness activities. "Best Management Practice" guidelines will be made available to industry and private consultants to ensure that the technology reaches the largest possible number of farmers. Paper and computer-based decision support tools will be developed for tactical and strategic assessment/management of alternative crop/pasture systems suitable for a range of soil and climate scenarios in the low rainfall cropping belt.