Managing weeds without chemicals

As published in Grower July 2011

Dan Bloomer and James Powrie – LandWISE Inc.

“I plant with precision, so that I can mechanically weed with confidence, and quickly too,” says John Evans.

Farming 271 ha at Dorie in mid Canterbury, John’s crops are largely grown for seed. The mix includes red beet and radish, mustards, carrots, linseed, spinach, cabbage, process peas, ryegrass and wheat.

John’s tractor is fitted with RTK-GPS and steers itself along the rows.  His implements have their own GPS receiver, which combined with a modified forklift side shifter, controls their position to within 2 cm. This ensures all his field operations are very precise.

High precision planting sets the crop up perfectly for mechanical weeding. This provides chemical free weed treatment and saves money too.

On John’s farm, chemical options are limited for some crop types with crop regeneration and field pansy unable to be treated. “Also herbicide resistance is reducing the efficacy of remaining options,” he says.  The weeds that affect many of the crops John grows are very closely related to the crop and extremely difficult to control with herbicides. Push hoeing isn’t seen as a desirable management option!  With the precision he now has at his disposal he can cover the ground very quickly.  The job he does is arguably better than push hoe quality.

“In Europe they have fewer and fewer chemical options available.  This happens as chemicals are banned or companies elect not to invest in re registering them.  The same thing is happening in NZ,” John says.  Precision mechanical weeding technology is leaping ahead in Europe.

John’s visits opened his eyes to the new technology and how it can be applied.  He imported a tine weeder, having seen it being used.  It bolts onto his existing Konskilde inter row cultivator and gives a far higher level of control with minimal crop damage.

Mechanical weeding only dropped out of favour with the development of herbicide options over the last 50 years. GPS has allowed it to be used again, getting the benefits without the downsides.

Cost savings relating to GPS are difficult to quantify, however John says that if he had to purchase GPS and start again tomorrow he definitely would.  He can work longer and work rate increases, yet he has less fatigue and feels better at the end of a shift.  This lets him achieve extra work after driving too.

See the LandWISE website for information and events  www.landwise.org.nz  Contact us and let us put you in touch with farmers who are making changes, or for relevant information on sustainable cropping through technology.  Thanks to Foundation for Arable Research for their research assistance on this farm.

2 thoughts on “Managing weeds without chemicals”

  1. Learning about precision agriculture and how it can help your farm is a great way to get great results. Do you know of any good sites to help me learn more about this technique?

Leave a Reply