For several years, the common mantra chanted by SSCA staff has been, "If you're going to direct seed, you have to have on-row packers". Ensuring good seed-to-soil contact has been a key element in the success of direct seeding systems. Good packing has proven critical, especially in years where the moisture situation in spring has been less than adequate. But Barrie Gwillim, a farmer in the Strasbourg area, has been able to achieve good seedling establishment without the conventional round packers. Barrie uses chains.
Seven years ago, Barrie purchased a John Deere 655 air seeder and over the years, has been modifying it so that he can direct seed with it. One of the main limitations to the unit is that it has a solid hitch so there is no consistent depth control. Barrie said he solved that problem. " I quit growing canola! I now grow only chick peas, lentils and cereals. The seeds of these crops are much more forgiving than canola if I get them in a little too deep."
Once he figured out his rotation, Barrie then turned his attention to minimizing soil disturbance when he seeds. He chose an Atom Jet boot with a carbide tip. After seeing what a neighbour had created, he then made his own liquid kit. The liquid fertilizer is pressurized so that it squirts out the tubes at the rear and to the side of the boots. As he couldn't find a packer that he really liked, he decided to go with chains behind the boot to close up the furrow. In the first year, Barrie had some problems with the chains. "Initially, the chains were bolted on without any shock absorbers", he said. "When a shank snapped back into position after tripping on a rock, the force would break the odd chain. So I took chunks of tire and put them between the boot and the chain and since then, I haven't had any problems". The chains aren't anything fancy. He uses whatever chain he can scrounge. Each chain is about 24 inches long except those near the tires. Those are about 15 inches long.
But does the system work? "You bet!" said Barrie. "I figured I wouldn't have too much trouble as long as there was some moisture in the ground. Then in 1998, I seeded my last field of wheat into dust. We had no rain and yet the wheat came up in beautiful little rows".
So why does it work? Barrie's theory on the success of the system has to do with the location of the chains and the seedbed. "I think the first key to this system is that the chains are very low on the boots. They're basically buried, running just over the top of the seed. If they were any higher on the boots, they would probably bounce up and around. The other key is that the seedbed is so firm at seeding. I don't harrow the fields after harvest or before seeding." The row spacing on his air seeder is 12 inches so he has excellent trash clearance.
Will the SSCA change its tune about the need for on-row packing? Not likely. In 1990, Gord Hultgreen et al. found that increasing packing force from 0 to 38 lbs, increased canola emergence by 37%. Emergence increased only slightly as packing pressure increased. In a study funded by the Western Grains Research Foundation conducted between 1997 and 1999, the effect of packing pressure on crop establishment was examined at three different locations in Saskatchewan. In the study, peas, canola and wheat were seeded with five different opener-packer combinations. Packing pressures were 0, 74 lbs, 124 lbs, 174 lbs and 224 lbs per packing wheel. Gord Hultgreen, a researcher with PAMI, was one of the scientists involved in the project. He said, "The results of this study were similar to those of the one completed in 1990. There was a great improvement in the seedling establishment between 74 lbs packing pressure and no packing but as the pressure increased from the first increment, there was little difference. The shape, size and down force of the packer didn't seem to matter a whole lot".
One of the features of Barrie's system is its price. To buy the air seeder and tank, openers, and liquid tank cost Barrie less than $20,000. The chains cost nothing. But Barrie doesn't have small seeded crops such as canola, mustard or flax in his rotation that require excellent seed-to-soil contact. In some years, chains may not be able to achieve that. An alternative to Barrie's chains is to use shank-mounted packers. When I called K-Hart Industries at Elrose, their manufacturer's suggested retail price was $140 per packer. To equip a 32 foot air seeder with shank mounted packers would cost roughly only $4500 more.
Barrie has been able to achieve good seeding success with his narrow opener and chains by seeding only those crops that don't require heavy packing. The system won't work for everyone. For those who have small seeded crops in the rotation and to guard against the dry years, the conventional wisdom of on-row packing with a packer wheel holds true.
Perhaps the new mantra for the SSCA staff could be, "The key to a successful crop is getting it established - every time. Make sure that whatever opener and packer combination you use can do that".