A recent survey of our 2012 spring seeded fields shows drill problems: My conclusion is that we have hit the wall on residue and our current methods of managing it. We are a season behind getting a handle on this issue. The cross-slot drill did much better at the Thornton place; but, depth of material, and inconsistent distribution shows problems with that drill as well. The straw distribution(management) of our Gleaner N7 is among the worst in the industry. Replacing the old girl with a newer machine with the micro cut straw chopper is one option we have been looking at; however, field observations show that they have distribution issues as well on these hills. The hillsides are left with ribbons of fine chop that will be difficult for disc drills to penetrate. The alternative for us is to replace our header with a Shelbourn Stripper head for the 2012 harvest. This head will leave most of the stubble intact, standing tall in the field, allowing a disc type opener to slip through the canopy and penetrate into mineral soil. Forget putting a hoe type drill in that environment.
Our drill was not used in 2011(all our crop was seeded with the cross-slot drill). We gave it a quick check, seeing that fertilizer and seed was being delivered to the seed row; however, we should have check more closely about seed depth. One half the drill did OK, but the other half did not. Field conditions changed and we didn't make the necessary adjustment. It will take more looking, but it appears that we have too much duff for this style and arrangement of openers and packer wheels. Although we seed shallow, in mineral soil, we leave a substantial mid row ridge. Deep residue combined with long, uncut straw, remaining after mowing the field, from wheel crush, promotes a drag and drop situation, resulting in an uneven seed row surface. The mustard crop with it's tiny seed is especially bad. Were it not for the insurance, we would tear most of it out and fallow the ground. This is an example where insurance will hold the money together, but you better not regularly farm for the insurance.
Some of the difficulties encountered by the cross-slot drill is from the uneven ground conditions left from our hoe drill. Drilling at a slight angle to our hoe drill rows is helpful for the cross-slot drill.
Our fall seeded crops using the cross-slot drill have all been excellent.
Some research on this topic follows:
Uneven Seeding is “the worst”
Crops seeded unevenly “are the worst,” says Dr. Yantai Gan, an Agriculture and Agri-Food Canada research scientist in Swift Current. Shallow seeded plants emerge several days faster, competing with the slower emerging, deep seeded plants for water, light and soil nutrients. Yields can be reduced by 50% or more and there can be 10 days between the first and last plants to emerge, which can be crucial in a frost year, he stresses.
Dr. Gan says frost or no frost, crops seeded shallow and uniform have a definite edge. They emerge more quickly and evenly, mature faster, and have higher yields. He led a three- year study that showed canola, mustard, and flax planted uniformly at 3⁄4 of an inch in early May emerged 3 to 5 days faster than seeds planted at 2 inches and had yields up to 25 % higher. With lentils, the yields increased up to 15%. A small plot study with wheat showed a 27% yield increase at 1 inch compared to 2 inches.
[My comment: --Twenty years ago another researcher from Canada reported that 90% of a crops (wheat) yield was from the plants that that emerged within three days of each other. Those emerging later were basically filler. It didn't make any difference whether the crop emerged in 5 days or two weeks --the importance was that it emerged all together.]
[My comment: -- A comment to a blog post on seeding depth of Peas -- shallow vs deep. Everyone has their own theory, and they all work to some extent. I base my idea of seeding peas deep (3-4") on a neighbors comment to me many years ago. His statement was " my neighbor seeds shallow (1-1.5"). I seed at (3-4"). His peas comes up earlier and looks fantastic, while mine look puny in comparison early on. I always out yield him in the end." My theory on this is that in our environment, deep seeding (provided you can seed consistently at depth) allows the root mass to access moisture longer than shallow seeded peas. Peas don't provide early canopy cover, so evaporation takes a big toll on moisture near the soil surface. Unless a DS drill has the capacity to adjust down force for differences in soils and residue, seeding 3-4" will be difficult to establish a stand with even emergence.
Emile deMilliano, Agricore United:
When I first started working with direct seeding equipment, I believed the one area where we would see major development would be openers. But besides some tweaking of original openers, I must say I’m a bit disappointed in the lack of development.
Both PAMI and AFMRC have studied the issue of openers and their conclusions were the same. “All openers work most of the time if properly adjusted for the conditions at hand!” It is not realistic to expect to find the perfect opener for all conditions.
AFMRC did suggest slowing down (< 5mph) as this did improve the performance of every opener they tested.
What do we know? We know organic matter levels improve over time. We know that carbon sequestration has, and is occurring. We have noticed better water infiltration and fewer problems with excess water. As well, lower soil moisture evaporation and higher moisture use efficiency has been apparent.
So what are we not seeing? We saw a period of increased N immobilization where microorganisms tie up free and available N as an energy source as they adjust to increased amounts of straw residue on the soil surface.
Banding much of our N below this straw residue does minimize the impact of immobilization.
Over time, however, as microorganisms adjust and organic matter levels increase, the rate of mineralization (release of N from organic matter) begins to outpace the rate of immobilization (tie-up of N by micro- organisms). This results in an extra boost of N available to the crop. Research in numerous other countries suggests it takes at least 15 years for this process to occur.
So does that mean we can expect a huge release of N starting in year 16? No, not really.
[my comment:-- Mineralization requires fuel, heat, oxygen. When we quit tilling, soil gases stabilized leaving high carbon dioxide content and relative low oxygen level. The "furnace" effect was reduced, so less mineralized N resulted. To calculate the amount of N needed for the crop it includes a calculation related to the OM content of your soil for mineralization that takes place under tillage. With no tillage, that number should be reduced and replaced by applying additional N. For our ground that means adding another 20-50 # of N until the soil microbes readjust as suggested above.]
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