Ground Cover North : Ground Cover 094 September-October 2011 - North
SEPTEMBER -- OCTOBER 2011 GROUND COVER Conservation farming 23 By Clarisa Collis n For Queensland grower St John Kent an ethos of 'no bare ground' forms the basis of his approach to farming, which is to maximise water infiltration and water use efficiency. His approach stems from a long-term commitment to conservation farming. The objective is profitable and environmentally viable farming using stubble retention and, where practical, continuous cropping using precision agriculture and tramlining. St John Kent, who farms at Jimbour, north of Dalby, sees his 'tram tracks' as a grid of narrow 'roads'. Like all well-used dirt roads, they require regular and rapid grading, and timeliness is essential to minimise the period that the ground is bare. This way, St John can optimise water infiltration by quickly resowing his paddocks to sorghum, chickpeas, wheat and opportunity cotton after each harvest. The need to swiftly renovate his tram tracks has led him and a neighbour, Brett McLaren, to develop a machine that combines the different stages of tram- track renovation into a single operation. Neighbours take a team approach to land management Managing surface water flow and soil moisture retention has brought neighbouring farmers into an 'across-the-fence' approach to precision agriculture "We previously needed multiple passes with different tooling, so we tried to integrate this into one machine," St John explains. St John and Brett devised their tram- track renovator by combining disc hillers (a cultivator attachment for covering plant roots with topsoil), a John Deere chisel plough frame, grader blade cutting edges, railway line and rolled hollow section (RHS) steel. Although the prototype is still a "work in progress", St John says serious deterioration of their tram tracks caused by drought and flooding in the past two years has pushed them to speed up its design. As one of the first growers on the northern Darling Downs to adopt conservation farming in the mid-1980s, St John also recalls modifying the front axle on a new front-wheel-assist tractor for making the switch to three-metre tracks. "We were mainly reacting to a need to match our farm machinery on the same tracks as the header because what we needed wasn't commercially available then." St John has been refining his conservation farming practices -- based SNAPSHOT Owners: St John and Edwina Kent, Brett and Helen McLaren Farm area: 1700ha Enterprises: sorghum, chickpeas, wheat and opportunity cotton Average annual rainfall: 650mm Soil type: black, cracking clay Soil pH: neutral Tractor: Case MX245 Header: John Deere 9670 Air seeder: Gyral twin-bin airseeder cart Spray rig: John Deere 4730 Planters: John Deere MaxEmerge planter and Barton single disc Conservation farming will be explored at the GRDC-sponsored 5th World Congress on Conservation Agriculture (WCCA) in Brisbane from 26 to 29 September. See www.wcca2011.org for further details. PHOTO: CLARISA COLLIS on a regime of maintaining soil cover to conserve soil moisture -- for more than 20 years, growing sorghum, chickpeas, wheat and opportunity cotton crops. He says the critical element has been fine-tuning farm layout, which on part of the farm has had to be adjusted three times to slow down and spread out surface water flow to a rate of less than 0.3 metres per second, particularly where water exits the tram tracks. To achieve this slower water flow, St John altered the direction of the tram tracks to make them run at right angles to the slope. This prevents 'pressure points' building at the end of the tram tracks. In areas where this was not possible due to the land's contours, the line of the tram tracks was adjusted 10 degrees to form 'dog- legs' in the rows. "Where the country is flat, the tram tracks also help to drain the field." St John says the design of neighbouring properties has also influenced the fine- tuning of his farm layout. The initial plan for the farm was based on topography maps provided by the Brigalow-- Jimbour Floodplains Landcare Group as part of a project to integrate floodplain management among landholders across the district. "Some of the water flow issues were originating seven kilometres away, but if you can identify the problem at the source it's usually easy to fix." This year, St John was able to assess and react to the patterns of flooding on his farm, as they related to neighbouring properties, using satellite images provided by a local catchment group, the Condamine Alliance. "That on-the-spot information was invaluable because it provided information about what was happening on the ground while the water was still running," he says, adding that this helped to identify issues with water flow on-farm and on neighbouring properties. "Farming practices and layouts in the catchment are constantly changing, so individual farms have to adjust to manage these new trends." In response to problems with water eroding headland tracks, the partnership with neighbour Brett McLaren has also led to an arrangement with another neighbouring grower that allows them to cross the farm boundary to turn their machinery in each other's property. This agreement has allowed the neighbours to sow crops along the natural drainage line of their boundary. He says the emphasis on maximising water infiltration and water use efficiency through stubble retention and continuous cropping, where practical, has also influenced the farm's cropping program. This commitment to conservation farming recently led St John and Brett to scale back the cotton they had grown as the mainstay of their operations since 1991. "Growing cotton was contradictory to the principles of conservation farming, and with continuous grain production we're now light years ahead environmentally and, we believe, economically better off in the long term as well." After 30 years of using a contractor for harvesting, the purchase of a new header is expected to further improve water infiltration and farming efficiencies by cutting the farm's trafficked area by 30 per cent. Upgrading the planting equipment from 9m to 12m is set to reduce the tram tracks to nine per cent of their total area. St John feels their dedication to conservation farming probably helped them to secure reasonable returns from their winter and summer crops after the flooding last summer. Although waterlogging and disease downgraded the quality of their chickpeas and sorghum, the harvested areas yielded 1.5 tonnes a hectare and 6t/ha respectively. □ More information: St John Kent, 0427 134 082, firstname.lastname@example.org Darling Downs grower St John Kent adheres to the philosophy of 'no bare ground' where possible.
Ground Cover 095 November-December 2011 - North
Ground Cover 093 July-August 2011 - North