As Published in ‘Grower Magazine December 2009’

Scott Lawson is a BioGro certified farmer who is using precision agriculture (PA) techniques on his Hawke’s Bay farm.  Produce from his farm is marketed through the True Earth brand. Scott is a founding member, and a Director of LandWISE.

At Lawson’s Organic Farms they integrate the best of organic, biological and conventional toolkits.

Scott’s philosophy is simple:  “The health of our soils relates directly to the health of our community.  My intention is to promote healthy soils to produce healthy food, for healthy people.”

“We adopted RTK GPS two years ago to drive straight lines and save costs.  GPS lets us do things we wanted to do before but couldn’t.  It is an essential tool for us now.”

“We operate a controlled traffic farming (CTF) system.  Precision GPS guidance keeps our cultivation, planting and mechanical and thermal weeding equipment on the same tracks.  We are also using GPS for capturing yield data, fertility and ph information and have begun mapping our soils with EM38.”

Managing compaction with GPS and controlled traffic

Scott has found that GPS allows straight lines to be driven by any operator, saving inputs and making operations quicker and cheaper.  RTK GPS guides the tractor to within 1-2 cm of the same wheel tracks, year after year.

Now he is using GPS guidance to control traffic and get on top of soil compaction. Controlled traffic farming is about deliberately driving on designated roads through the crop and keeping compaction in one zone.  The beds or gardens are then kept relatively free of compaction.

Scott’s controlled traffic system is seasonal, because current tractors and harvesters have different wheel track widths. All operations except harvest are in the controlled traffic system so plants get the growth benefit.

GPS guided mechanical and thermal weeding

The chemical weed management tools available to organic farmers are very limited. So they tend to make more use of hand, mechanical and thermal weeding.

Hand weeding has been used extensively in Scott’s operation.  It is slow and expensive, and labour management is a big consumer of time too. Precise GPS guidance has allowed bullet straight rows to be planted and mechanical weeding machines to be guided close to the crop row.  This has reduced expenditure on hand weeding operations.

Thermal weeding is also used, with steam applied to kill emerging weeds.  Timing is critical and so the controlled traffic system is a bonus.  The formed tracks have an enhanced ability to carry traffic, even when ground conditions wetter than ideal.

Mechanical and thermal weeding, as pursued by organic growers like Scott, are receiving more interest from conventional growers.  Some weeds cannot be easily taken out of some crops with selective herbicides.   Chemical options are declining as products come off registration and as plants evolve chemical resistance.  As chemicals are deregistered, growers lose ability to rotate chemistry and avoid evolved resistance.

Conventional farmers, John Evans and Hugh Ritchie, are two other LandWISE members who have adopted GPS guided weeding.  John grows vegetable seed and grass seed crops.  Chemical options are not giving adequate weed control, especially in his seed carrot crops.

John uses RTK GPS to guide a Kongskilde mechanical weeder within 50mm of the planted rows.  “This is reducing the hand weeding bill and offers improved weed control.  It has an added benefit of aerating the soil surface when a rainfall crust has formed, letting the soil breathe again,” John says.

Hugh uses GPS guidance supplemented with camera implement control to weed squash, fresh and process vegetables with a Danish Eco-Dan system.”  It has reduced a major labour bill for us.  And using less residual chemical is a direction we are pleased to be heading in.“

Scott is intrigued by the view some folks have of organics.  “If I asked some fellow growers if they’d like to try the organic weeding methods I am applying, they’d likely tell me where to get off.  If I ask if they’d like to weed mechanically using GPS and eliminate expensive selective herbicides from their program, their ears prick up”.

The LandWISE website www.landwise.org.nz contains articles on precision agriculture and many resources and tools.  It is also a place to comment, chat and ask questions about where to go to learn more.
Visit the website to learn more, or contact James direct on 06 6504531 or 0272 757757.