Agronomic opportunities
Establishment of permanent wheel tracks combined with use of a sufficiently accurate guidance system can provide opportunities for in-crop agronomy and soil management without causing unwanted mechanical damage to crops or soil compaction.
Opportunities include:
- Inter-row sowing which has shown to improve seeder performance, reduce potential for root disease and also assist crops such as lentils ‘climb’ the wheat stubble rows to facilitate harvest.
- Close to or on-row sowing to enable access to moist soil in water repellent areas.
- Inter-row shield spraying or mechanical weed control, with care to avoid development of herbicide resistance.
- Band spraying directly over the crop row, to reduce chemical costs.
- Relay planting (planting a new crop or pasture into an existing one before harvest). Banded application of lime, manure, fertiliser or other products.
- Directing chaff and weed seeds onto the wheel tracks for easier management.
- A more compatible system of cropping for in-paddock large scale trials than with machinery that has poor matching of widths and no control of cropping traffic.
Costs
The cost of a transition to CTF varies from farm to farm, depending on what equipment is already on hand. Following is a guide to the cost of upgrading to a CTF system:
Tractor: Front-wheel axle; new cotton reels $3600. Trailed sprayer: axle conversion $3000. Air cart; axle conversion $0-3000. Harvester: Auger extension $1600-2000. Chaser bin extension $16 000. Total base cost: $24 200-27 600. If GNSS 2cm RTK is required + $18 000. Total cost: $42 200-45 600.
It is not always possible to make these changes in one season, so many farms are developing a CTF machinery investment plan in line with their usual machinery change over schedule. In some instances this has meant it has taken a period of 6-7 years to develop a fully matched system.
Challenges
CTF involves a shift in mind-set to a priority of soil health and change in machinery and farm layout that are key components of farm operations. Thus there can be some challenges to consider such as:
- Seeding and harvesting capacity, how to accommodate size and capacity increases for more efficient operations, yet maintain a CTF system. Increased seeding speed and loading capacity can help increase seeding capacity without increase of seeder width.
- High cost of changes in some cases (depending on current machinery and changeover preferences).
- Spreading widths (especially lime and straw), 9m may be the maximum width of spreading of limesand and 12m the maximum width of spreading of straw.
- Burned windrows leading to uneven distribution of nutrients. Swath movement, chaff removal or harvester repositioning in dry harvests soil conditions may be possible solutions.
- Wheel track sinkage and erosion. Use of alternative (dry) tramlines of wing tramlines fro SP sprayers may help, as well as wheeltrack renovators to refill rutted tramlines.
- Staff and consultant training to stay driving on the wheel tracks. This is gradually improved with more education and understanding.
- Guidance compatibility between brands and drift between seasons; this needs careful attention when selecting guidance systems.