[Click on "CrossSlot" or "direct seeding" label at bottom of post for more posts on subject.]
In Summary:(as of 10/9/12)---- The Cross-slot opener did a good job considering our inexperience with the drill & tractor. A very complex system with GPS, mapping, variable rate for three products, seed tube monitoring, auto steer and auto boom control. We started drilling on 9/12 with the capability of 100% crop emergence, but that didn't happen. With experience we'll do better about seed depth control, and the plugging that we did encounter, although minor. The Cross-slot system has great potential, but not yet perfect. Our concerns are: 1)--Tractor horse power and weight required to push 30 straight running notched disc's 4-6" deep in uncultivated ground. 2)--Acre cost for disc and blade wear. 3)--Plugging of openers.
More Detail:--- Our chemical fallow had good moisture in the seed zone; however, the soil surface was drying and hardening do to the sun and wind. We probably should have started seeding a week earlier. The drill has an auto depth control system to keep the seed location at a desired position; however, we didn't do well at monitoring, and adjusting the hydraulic pressure for that system; hence, some of the seed was placed to shallow. Technically, this monitoring should not be required. Sensing, for instance, 40 pounds resistance on the packer wheel from the ground should have been enough to keep the opener at depth. It appears not to be that simple.
I have known for many years that a rolling disc can require an amazing amount of weight to penetrate dry hard ground. Thirty disc's working at depth, coupled with blades on each side acting like a brake from the pressure of the soil against them, create a significant draft. We have some concerns that our Case 4994 wheel tractor with 400hp and weighing 38,000 pounds is of sufficient size to pull a drill of this type with 1500g of aqua, 60bu of seed, and 350g of starter solution. These are the volumes we currently have with our hoe type direct seed drill, and it is a relatively easy pull.
A few openers were fitted with carbide inserts on the blades. They were causing rapid wear on the disc. Some of the problem is due to the spring plate that holds the blade against the disc. The current design has dense rubber bumpers glued to a plate which press against the blade, and hence, the disc, and is secured to the opener frame with a single 12mm stud. When the spring plate is secured to the opener, it puts significant pressure against the disc through the blade, even at rest. When the drill runs across our sloping terrain, the disc's bend from the weight of the drill. The upper side of the disc has increased pressure applied from the blade, and the lower side can develop a gap between the disc and blade which allows residue and dirt to enter the seed or fertilizer channels causing a plug. I believe this situation could be rectified by a slight shape modification of the spring plate allowing some rocking motion, and by putting a rubber washer under the stud that secures the spring plate to the opener body. This allows more movement of the blade, allowing it to follow the disc as it flexes (bends), and at the same time reduce the pressure exerted on the disc. This should help reduce draft as well as reduce the incidences of plugging. Reducing this excessive pressure on the disc applied by the blade should reduce the wear issue as well.
