Why do some farmers insist on modifying existing equipment or build equipment based on their own design when there's perfectly good equipment already on the market? Well, the reasons can be as varied as the farmers who undertake such projects. Very often, economics are the driving force behind some projects. Many farmers are either unwilling to make such a large investment in a commercially made machine or simply do not have the cash flow to justify the purchase. Some farmers are a still unsure of the direct seeding technology and do not want to make a large capital investment until they gain more experience in the system. In other cases, there simply is no machine or opener currently available on the market that works to the farmer's satisfaction on his land. These same reasons are also the motivation that fuels farmers ingenuity and has often resulted in a commercially marketed component or machine.
Tom and Owen Cairns, a father and son team from Coronach, are two farmers who have designed and built their own 50 foot air drill to suit their farming conditions. Their unique design allows for flexibility, yet ensures good penetration, even under adverse soil conditions. In addition to these reasons, economics also played a big role. As Tom Cairns noted, "At the time we built our seeder, most new 50 foot air drills cost around $100,000. Ours cost between $25,000 and $30,000." The Cairns built the drill during the winter of 1993 and have used it for three seasons now, seeding about 3800 acres annually.
The air drill consists of six, eight feet four inches wide sections. Unlike other air drills, the sections are not connected directly to each other. Instead, they are each attached to the main frame running horizontally above the sections. The sections are connected so that they can move up and down as well as laterally, each section moving independently of each other. Another innovative design feature is that due to the way the sections are connected to the main frame, the sections are pushed, not pulled through the soil. This provides downwards pressure to ensure adequate penetration.
The Cairns have also used some commercially available components on their air drill. They are very happy with the packing system based on the Concord pneumatic tire system. The secondary manifold system is from Morris and they have added sensors on each run. A monitor in the tractor cab monitors all 60 runs and can show which run is having a problem. They originally designed their own shank with Bourgault 450 pound trips. Due to some opener problems, they changed to a Bourgault C shank and trip system. The row spacing is 10 inches and the shanks are 40 inches apart, providing very good residue clearance. The distance from front to back is less than 11 feet which helps to maintain uniform depth control over uneven ground. The opener they used this year was a four inch Key Ag chrome sweep so they could apply fertilizer with the seed.
Since Tom and Owen farm on some hilly land, skewing is always a problem. To reduce this they added a coulter at each end of the drill and probably more importantly, modified the front castors. They have incorporated an assembly on each castor which operates like a trip mechanism to keep the wheels running straight. When a certain pressure is reached, the castor can rotate. This dramatically reduces skewing on most side hills, yet allows the machine to make sharp turns.
The air tank is a modified Frigstad with 75/65 bushel capacity. The Cairns have changed the mounting hitch and carriage of the tank to the seeder so it is stronger and prevents skewing when the outfit is backing up. The metering wheel for the air tank was moved to just in front of the tank. An oil pump was mounted on the wheel which drives the metering system. The wheel is tied into the main hydraulic system so that as the seeder is lifted, the metering wheel automatically lifts off the ground first. The wheel touches down first when the seeder is lowered into the ground.
Tom and Owen are firm believers in the direct seeding system now that they have several years of experience. They have also noticed a dramatic reduction of weed problems on their direct seeded fields. As Tom noted, "Anyone who direct seeds with lower disturbance can expect 50 to 75 per cent reduction of weed problems in their direct seeded fields in the first few years."
Modifying existing equipment can be a viable option to change from a conventional method of farming to direct seeding. Modifications do not necessarily have to be as elaborate as the Cairns. There are also modifications one can undertake on existing equipment that can allow it to direct seed. Some of these will be profiled in upcoming issues of the Prairie Steward.