Rooting out weeds and staying on track with robots

Friday, April 4, 2014

Robotic systems for faster on-the-move weeding and more backing for the controlled field traffic concept hit the headlines in springtime Europe

by NORMAN DUNN

Forward-thinking machinery people are tackling high labour and machinery costs in Europe by turning increasingly to robotics out in the field.  It's a welcome move and one of the prime players in this sector is the British Garford company. Its camera-guided robot systems for weed control in growing crops are already successful. But an uprated Garford Robocrop InRow Weeder comes this spring using video image analysis techniques to locate individual plants. Weeding hoes mounted on the same tractor are then automatically steered to remove weeds inter-row, as well as between the plants. Launched this year from the same company is a robotic spot-spraying system, also camera controlled.

Developed for use on transplanted crops such as lettuce, cabbage and celery, Robocrop InRow hoe can also be used on most crops planted with regular spacings where the plant foliage is clearly separated from the next plant. Forward speeds of up to three plant spacings per second are possible, and the largest model can handle up to 18 rows at a time (up to six metres working width.)

The company's crop imaging system with Robocrop's grid matching technique gives accurate row following, even on narrow row cereals and in carrot crops. Images are analyzed at a rate of 30 frames per second and the hoe steering adjusted via a hydraulic side shift. Accuracy is generally 15 millimetres at the camera. But add a disc system and accuracy of better than 10 millimetres is achievable, says the company. Working speeds: up to 12 km/h.

Using the same camera system, Garford has also launched an automatic spot-spraying system, successfully tested last season for knocking out volunteer potato plants in field vegetable crops, but suitable, says the company, for work in a wide range of crops. The video-guided spraying robot can deal with up to four weed plants per second. A welcome move: the spray robot is introduced with an 18-metre working width claimed to give the rig a coverage of 50 acres per hour. Controlled Traffic Farming (CTF) commands a widening interest as farmers find that much higher yields and lower input costs are almost immediate responses to the strategy of establishing permanent tracks across fields for all traffic and leaving the rest of the area completely unwheeled. Especially where non-plow minimum cultivation systems – or direct drilling – are adopted, practical trials in the Netherlands and in Britain show that the result can mean 80 to 90 per cent of the field surface area remaining free from tracking. With conventional systems, this is very often the other way around!

Tests on Essex farmland in 2009 showed that CTF in this case cut fuel bills for cultivations by 10 per cent compared with non-CTF fields, and operations were carried out with an 11 per cent saving in time.

These tests used a commercial in-tractor parallel steering system (John Deere Green Star SF2) for tracking. For permanent systems, though, a Real Time Kinematic (RTK) system is recommended. This gives an accuracy, year-in year-out, of plus or minus two centimetres. Tim Chamen founded and now runs the U.K. arm of the organization, CTF Europe. He says long-term yield increases recorded between the tracks with CTF include up to 25 per cent for arable grass silage and oil seed rape with a plus of eight per cent recorded for wheat. Chamen adds that cultivations are easier after just one year of CTF with required draft 60 per cent less at 10 centimetres below the field surface.

One problem with CTF and combining crops is that it's often difficult to load chaser trailers alongside a moving combine-harvester and stay on any established tracks. This is why manufacturer Richard Western now launches a side-mounted movable conveyor belt for chasers. The trailers (up to 24 tonnes capacity) can then follow GPS-controlled tracking with the elevator powered out on one side to load grain being discharged from working combines. Retrofitting to all existing Richard Western trailers is possible. Price of the cross elevator (controlled by tractor hydraulics) in British dealerships is the equivalent of C$40,000, says the company.  BF