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Bourgault 3720 coulter drill seed placement issue

8K views 7 replies 2 participants last post by  waynech 
#1 ·
I have a bourgault 3720 independent coulter 50 foot drill with a 7550 leading bourgault cart. when seeding my lentils and peas this spring everything came up real nice. when i switched to durum i dropped the mid row banders to put anhydrous down. i pull a double nh3 trailer with 2 1500 gallon tanks. i have spots in the field and have narrowed it down to the left wing section that the front row of seed openers are leaving blank rows when going on a sidehill. the seed rows on the rear openers are fine. when digging down in the rows with no plants growing or a few scattered ones i have found seed and it seems to be at the correct depth, but the seeds looked rotten, {the germination on the seed was 94% so its not a germination issue, and if it was it would be on all rows.
was thinking that the drill may be drafting a little and the seed is getting next to the mid row bander furrow and the anhydrous was burning the seed, but i think if that was the case is would happen with more than on one side and one row of openers. the spacing of the seed and mrb openers is correct. at a loss here everywhere else the crop is perfect, could the weight of the nh3 tanks be pushing the drill. if so why is it always just the left wing section. the hills and side hills are not that steep. i never noticed this problem last year when the drill was new, the only thing different this year is i have a case 580 quad trac pulling the drill, and last year i had a deere 9560 with triples. anyone out there have any ideas i have contacted my dealer and they are stumped also
 
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#6 · (Edited)
First off there has to be a plausible reason why the seed has rotted in these selected rows. I think those seeds were in moist enough soil, and they were shallow and warm enough to break dormancy and germinate almost right away. They likely had a very thin dry zone below them and consequently became stranded and died as those rows aired off the surface moisture to the atmosphere. Over time, the now dead seed, would rot with no chance of revival from a timely rain.

The five-plex frame has no wing down pressure on the end sections, only the intermediate sections carry any mainframe weight, which is of course mostly beneficial for operation. However anytime the opener down pressures on the drill in general get near the physical limitations, the openers on the drill which includes the the fixed upward thrust from the MRB's will begin to randomly elevate the drill frame higher above the soil in the least weighted areas of the machine, which is usually the end of the end wing. The exception would be if the intermediate wing down pressure exceeded recommendations in which case the main frame could raise.

Often this begins with the working tire diameter increasing on the end wing as it is relived from it's normal load if the combination of opener down pressure exceeds the weight of the end wing. Sometimes because of the low tire pressures needed on a lightly loaded tire, it effectively acts as a spring that is being unloaded. If the down pressure is high enough some implement wheels can actually start coming off the ground on flat going, which is hard to detect in no till situations.

Since the toolbar is designed with a controlled flexibility between the front to the back, either the rear, or the front, can be the first to start to unload the tires. In this case with the MRB's running with some decent depth along with the downforce of the seed openers, it likely elevated the front and the end of the wing a slight amount.

Running an extremely low air pressure on the front tires of of the end wing can help this. I believe I run 7 or 8 PSI in the end wheel on the front on a 70 foot 3720 with the high flotation wheel option. Without doing this it would barely be possible to touch the ground at the outer ends with the MRB's when the seed openers are at the upper limits of down pressure and the travel speeds are on the high side. The down side is the tire appears half flat when turning on the headland with the drill weight on it.

Even if the front row of seed openers were reaching down from the frame an unusual amount, the paralink design should keep the disk penetration proportional to the gauge wheels and achieve normal planting depth. However as the down pressure cylinders hit their stroke limit on the now floating wing, the openers on that section would no longer be functioning 100% independent because they are stroke limited from going any further downward.

As far as the surface moisture on that one section being enough to germinate the seed in a normally too dry zone, I can only presume it was the discharged soil from the MRB's running in good moisture just in front of the front row of seed openers, and placing that moist soil on top of the dry field surface. This would be magnified by the increasing compound angle to the MRB discs as the wing tilts upward randomly for a few seconds pivoting over its somewhat centrally located tires.

I know it seems odd that it's only one side, but it has to start somewhere, it's usually an indication that one of the physical limits has been reached of one kind or another, and too much down pressure has been selected for the situation. Most likely a very tiny reduction of opener down pressure would solve the problem without creating the next one to solve.
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#7 ·
been going over all possibilities and have talked to the dealer and the local rep for this area and they are going to come out ant take a look. i am thinking it may have something to do with the down pressure also but i ran it the same as last year, in that 700 psi range and had no problem. i pulled out one shim on the mrb's this year because last year i don't think i had them deep enough so now i have the one thick one in that fastens together with the screws and one thin shim, and it sure made a difference on the anhydrous placement very little smoking behind the opener. and i had the mrb opener down pressure set at 1350 where bourgault recommends. in more looking at the fields it is always on an area that the drill is coming to a side hill and the left wing is on the upward side and the right wing is lower. when the drill is pretty much level left to right everything is fine. my son said he noticed that the pressure gauge on the switch box in cab of tractor was always dancing up and down a lot but not sure if it was worse on the sidehills. i am going to try and figure out how to upload some pictures on here that i took and sent to bourgault.
 
#8 ·
i have bourgault checking on some things for me but my son and i were taking the other day and we are wondering if my hitch on the seeding tool might be the problem, as this spring when i turned the drill around in the yard i turned to sharp { i had a quad-trac on the drill my first year with one and i wasn't thinking about it turning way sharper that my wheeled tractor with triples on it } anyways the duals on the cart rubbed hard enough on the drill hitch where it bent it up a little bit and also bent in inward, these bends are visible when looking at the hitch. could the bends have changed the way the drill follows, there fore affecting the left side when starting up a side hill and the left side is on the high side and the right side is still climbing, and with the nh3 tank pulling cause it to draft enough so the front row of seed openers on that left wing are laying the seed right next to or in the same furrow at the anhydrous.
 
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