I farm 2200 acres of heavy clay in the Wilcox and Milestone area, 40 km south of Regina, as a joint venture with a neighbour. Nine hundred and thirty acres has been continuously cropped since 1980, mainly with discers. The remainder of the land has been cropped in various rotations since 1980, primarily with discers.
We have rented several types of direct seeding equipment from several different manufacturers over several years, trying to find a type of equipment that would replace discers. Even though we had a Straw Storm on our combine for most of these trial years, straw handling following the discers increasingly became a problem. This problem was more severe in wet, cloudy weather. Since discers leave an uneven field, harrowing is almost mandatory after seeding with a discer. After encountering two cloudy, cool stretches in successive springs, we decided to look seriously at an air seeder with the idea of one pass seeding and fertilizing. This was in the fall of 1991.
In the spring of 1992, we arranged to have several hundred acres custom seeded with a 665 John Deere that had a narrow opener and eight inch row spacing. After 320 acres with this machine, it became evident that trash clearance with this spacing was causing severe plugging problems. We had to stop this operation and finish seeding with the discers. From this experience and observing Dr. Guy Lafond's experiments at Indian Head Research Station with row spacing in soil similar to our own, we decided that 12 inch shank spacing would be the most practical in our heavy clay conditions. So the search began for an air seeder that would come closest to meeting our requirements and soil conditions. The features we looked for in an air seeder were:
The two areas we felt we would have trouble with on an air seeder were the openers and packer wheels. We weren't wrong in these assumptions. As you can see in the slides, the lead shank places the fertilizer, while the following shank places the seed above and slightly to the side of the fertilizer. The packer wheel follows in line with the fertilizer shank, packing the seed with the side of the packer wheel. The seed tube depth is controlled by removable pins on the bracket, which adjusts the packer wheel up or down for depth control. The fertilizer tube is adjusted independently by hydraulics on the cultivator frame.
Since our soil is always moist and gummy when seeding and with fertilizer opening very close to ground level, some openers began plugging with moist soil. Because the opener was designed to shoot the fertilizer directly behind the opener, it would catch moist soil and plug. When we purchased the machine from Jim Halford, the owner of Conserva Pak, we told him of our concerns about plugging. He assured us that he and his engineers and technicians would work on with us to incorporate design changes that would work better in our soil conditions. Jim and his staff have done a fine job in meeting that commitment. The seed tube has given us very little trouble with plugging, so they have been basically left unchanged. Note no opener on the seed tube. It is a vertical drop tube with the bottom opening cut higher at the back, with a reinforcing rod down the front.
The fertilizer tube was designed to drop straight down until the bottom six inches, then bends forward to shoot fertilizer in close behind the 3/4 inch wide opener. After speaking to Jim Halford about our plugging problems, he suggested cutting the fertilizer opener open at the back, up the tube about 1/2 inch. After trial and error, we have cut further up the back of the tube about two inches. Since our soil doesn't fall back into the opener trench quickly, the fertilizer is still falling into the opening, even though the fertilizer is not being shot directly behind the fertilizer opener. This has eliminated most of the curve. The fertilizer must follow down the tube and with the opening being much higher above ground level, it is much more difficult for mud to stick in the tube.
The other problem we encountered, was the packer wheel plugging. The first packer wheel that came with the machine was a 16 inch diameter poly wheel, tapered slightly from the axle to the outer edge. Conserva Pak supplied a scraper to clean the edge of the wheel. This scraper was a small poly wheel that was free-wheeling and turned across the edge and perpendicular to the packer wheel. This scraper wheel helped somewhat, but would plug if some straw or cereal root got caught between the packer wheel and the scraper wheel. Thus, we removed the scrapers.
The greatest problem plugging problem was on the side of the packer wheel. Mud and straw would stick on the side of the packers, eventually plugging between the bracket and the wheel. After discussions with the Conserva Pak engineers, Jim Halford, and ourselves, it was decided that a rubber tire might work better. I called several places in Regina and finally found a bicycle shop that had a tire that looked promising. We installed a 16 inch bicycle tire, about two inches wide with a knobby tread. This worked surprisingly well. The spokes of the wheel had much less surface area for mud to stick to, therefore, the spoke area rarely plugged up. The rough tread of the tire had enough flex to keep the mud build up to an acceptable level. Jim Halford installed these packers on some other machines in heavier soils with good results during the spring of 1994. we realized that the exposed bearings on the bicycle wheels would not last long. These bearings were injected with grease before installing to give them added life, but this was only a stopgap measure. The next step for Conserva Pak engineers was to design a wheel and bearing assembly , incorporating a rubber tire of this type. This was accomplished by the spring of 1995, with both pneumatic and solid rubber tires available for use. The solid rubber tread was flatter than the pneumatic tread, thus didn't mud off as readily as the pneumatic type. As of late December 1995, Conserva Pak has decided to manufacture a non-pneumatic tire with rounded edges, much like a bicycle tire. We believe this type of tire will decrease the plugging problems.
As you can tell, we haven't solved all the problems of using air seeding machines in gummy soils. Since our type of soil makes up only a very small percentage of the total soil types in Saskatchewan, it is very difficult and expensive for manufactures of air seeders to build a machine that works well right off the assembly line in heavy soils. However, our machine with its modifications, is much improved from the first day we started using it. I am quite sure that with the help of the manufacturers and our own ideas, we will have many more changes to our machine to make it work better.