secondary tillage: tools and concepts

[Andy Carson]

I have been performing a short fallow on a couple plots to try to get rid of some perennial grasses (IE quackgrass) and a few other weeds and to prepare a good seedbed for planting corn and sunflowers. The ground was mostly disced last year and planted with a cover crop of triticale and oats. I started with a springtooth at about 2 inch depth, then disced to about 4 inches, and have been following this with a springtooth at 2-3 inches. The springtooth does an admirable job of mixing the soil, but this does not seem to be very effective on the perennial grasses. The spacing and width of the teeth leaves strips that are not undercut, and although some dirt is thrown on top of the grass, this is not very effective at inhibiting growth. I fact, I find the action of throwing dirt on top or grass to be harmful, because it hides the grass without killing it. I think I would prefer a tool that undercuts the grass and weeds better without quite so much mixing action. I think a tool similar to a cultivator with wide sweeps would work better for what I want. With a springtooth, there is a temptation to go deeper and deeper when weeds are not covered or terminated. Covering doesn’t work for many weeds, though, and deeper is not the way I want to go… I thought before I went to the trouble of making this tool, I would see why the springtooth is so darn popular. Maybe I am missing something or am not using it to in the best way… Perhaps a springtooth is designed more for following a moldboard plow where the grass is already buried and the action that is needed is more mixing and leveling and terminating annual weeds. I guess I am attempting to start of a discussion on techniques of secondary tillage, specifically on the importance of a “mixing” action versus an “undercutting” action for weed termination. I am curious what tools others use and how they like them. I am also curious about what the levels of weed termination are reasonable to expect with these different tools/techniques. I think I will always fight perennial grasses to some extent; perhaps this is as good as it gets? Sorry to make the discussion so wide ranging… Any and all thoughts are helpful.

[Tim Harrigan]

Andy, sounds like you are finding our first-hand how tough it is to control quack grass with tillage. Quack grass reproduces both by seed and underground rhizomes that are very aggressive and extensive. So they have extensive root reserves to re-grow after you disk them down. As you are finding out, if the top growth is not buried it will regrow. But that is not the tough part. New plant emerge from the roots. And even if you cut up the roots, plants can emerge from the cut pieces of root. So with tillage the technique is to till it, and then when it begins to regrow, till it again until it exhausts the root reserves. And you will have the weed seed bank to deal with for a long time. This time of year tillage is tough because there is adequate moisture to keep the plant going, and it is cool and moist enough that the exposed plant pieces do not dessicate. Field scale tillage control is probably more successful in summer.

From what you describe, it may be best to moldboard plow and then disk and harrow as necessary to keep the weeds knocked back. The other option is chemical weed control to get back to a manageable situation and start from there. Good luck.

[Andy Carson]

Thank for the thoughts. Part of my difficulty in thinking about this is that I am truly unsure of how much of a problem it is. I figure that using a conservative tillage techniques without the chemicals I am always going to be fighting the quackgrass (or similar) at least a little. Some spots in these plots are free or grasses, some spots are moderate. Nowhere it is even close to forming a “sod” or even a thick mat. If I have zero tolerance for quackgrass, I will be moldboard plowing every year, which defeats the purpose. I need to figure out how much is too much. I think corn is pretty sensitive to grasses, I am not sure about sunflowers. Both would provide alot of shade if they can get a good start, and I can cultivate between rows, which I am hoping will give me a chance to cultivate in a way that might approximate a summer fallow.

I am going with the strategy of till, let the grass regrow, and then till again. I have read about the dessication technique, but have little faith in it in my climate, esp in spring. Truth be told, I am not 100% sure what species every peice of grass in my field is partly because I did plant some covers and I partly because I am trying to till everything very early and I am better at identifying grasses when they have collars and/or seedheads. I am basically identifying them as “problem grasses” if they have an extensive root system and if they survive the tillage I have performed already. Problem is with the springtooth, I am only getting a partial kill and uprooting action with these regrown grasses. I was curious about different tools, perhaps something with wider sweeps to make certain everything is undercut. It makes sense to me, but I wonder if 1) anyone has experience with a tool like this in a small scale situation or 2) quackgrass (and similar) is so tough that is it unreasonable to expect any sort of tillage (other than moldboard plowing) to knock it back an appreciable degree.

Alternative approaches.
1) Intential overgrazing (I have 24 geese that will keep this area stripped bare for a good while, esp since it’s close to bare right now). Of couse, I am going to have to feed them a whole lot more than I have if I keep them off the good pasture.

2) Till a bit longer and plant buckwheat. I read that this works, but I have to say I have not had good luck with the use of cover crops to outcompete these perenial grasses. Even rye, which was SUPER vigerous in my hands, had some perenial grasses (including quackgrass) in the understory. It did make a big dent, btu this gets back to the question of how much is too much and how much tolerance makes sense.

[Kevin Cunningham]

quack grass is a nasty one and around here we have what we call canada thistle, a thistle that runs with rhizomes, a real bugger.
I have heard of farmers with nasty problems using a summer fallow and using more of a cultivator type approach, because you don’t want to cut the roots up but rather dessicate them out. The williams tool system, from market farm, might be a good start. I have used it with tractor cultivation of row crops it does a bang up job. Exactly what you’re talking about, sweeps that undercut and then follow by wire fingers that scratch and up root the plants. When properly used it flips the plant roots up in the air to dry out and die. I can even picture a just the fingers to scratch and flip the grass out. And honestly the moldboard doesn’t get all the quack grass either. We always live with some of it. Here is the link to market farm:
http://www.marketfarm.com/cfms/williams_tool_system.cfm

[Iron Rose]

I have run a hot wire about a foot off the ground around the area and run some pigs on the plot . They will roat up the ground and eat the quack roots and keep the ground stired up, keeping thee quack from getting started again.

Dan Rasmussen
Iron Rose Farm

[Jay]

I agree with the above – it’s a tough one to get a handle on. It loves open ground, however it doesn’t like competition. i.e. fast growing overshadowing plants like heavy winter rye crop in autumn or buckwheat sown heavily in the warmer months. Or for smaller areas, cover with cardboard or what ever will NOT let it get it’s green shoots up into the sunlight. We have almost eliminated it from our market garden using smother crops. Pigs also do a job on it though it may take some specific management of them to get them to really clean it up. Jay

[Tim Harrigan]

@Countymouse 34299 wrote:

If I have zero tolerance for quackgrass, I will be moldboard plowing every year, which defeats the purpose. I need to figure out how much is too much. I think corn is pretty sensitive to grasses, I am not sure about sunflowers. Both would provide alot of shade if they can get a good start, and I can cultivate between rows, which I am hoping will give me a chance to cultivate in a way that might approximate a summer fallow.

I agree that your expectations will drive your approach. Of course, the quack grass and other weeds will take nitrogen and water, and these are usually the limiting inputs at least in corn production, not sure about sunflowers. Not sure what you are thinking about for nitrogen management, but that can be a challenge with organic corn production. How much reduction depends on how much you can suppress the weeds. The fact that you will probably plant in wider rows will work against you as far as row closure and shading out the quack grass, and cultivation can do a good job between the rows, not always so great in the row.

There are some modern tillage tools that do a better job with surface weed control, one I am familiar with is the Kongskilde Triple-K field cultivator. It has spring tine shanks and goose foot sweeps and they do considerably more surface mixing than the springtooth harrow. I am pretty sure I have seen it at HPD but it was probably on plowed ground so hard to assess for weed control. I think speed of operation will influence how well it works, and I have only used them with tractor power so faster ground travel.

If you get good with a cultivator you will be able to throw soil into the row between the plants which would help somewhat. Weather has a big impact on how well row cultivation works, in a wet year you are going to have a fight on your hands.

[mitchmaine]

andy, there is an old hd tool out there called a weeder. not sure how easy it would be to find one. it resembles a dump rake only with many more points. so many that psi is minimum, and it walks on the surface of your seed bed upsetting new emerging weeds and drying and killing the root. used after you prepare the seed bed and depending on how soon you plant, a few times until the plants reach a few inches in height. i have one modified for three point hitch and use it but even still, sooner or later, if you aren’t going to poison, then you have to get down and handweed. bindweed is our biggest nuisance. chop it five times and get five new weeds.

[Kevin Cunningham]

I know they used to use horse drawn version of the rod weeder in Oregon on huge plantings of wheat. I have seen great pictures of the wheat production in Oregon, it is the convergence of large scale ag and the very end of the major horse drawn era. We’re talking hundreds and hundreds of acres grown and harvested with draft. Any how it got me thinking because the book I saw this in talked about a rod weeder. Here is the modern tractor based version: http://www.bighambrothers.com/rodweeder.pdf. In my understanding it was used post tillage, and prior to planting for weed and grass control.

[Rivendell Farm]

There is no magic bullet to control quackgrass without chemicals. I have had good luck with a combination of summer fallow and buckwheat plowdown planted at about one bushel to the acre, but it takes a few years of the right rotation to beat it back. The disc chops up the connecting roots between plants, allowing each root piece to start a new plant. A springtooth drag, on the other hand, should be able to flip the roots out of the ground so they dry out if conditions are right. Years ago I had a weeder like Mitch described. It worked best when used on annual weeds just after they germinate and have only a couple leaves, great for weed control in corn before the corn even emerges. But it won’t do much against quackgrass. Bob

[mitchmaine]

any wisdom in burning or discing crop residue and trying to kill first weeds before plowing them down? we used to disc all the ground before plowing but time put a crunch on that and we don’t seem to get a chance. but i think it worked a little.

[bendube]

We’ve been working up a half acre field that was in no-till human powered vegetables for a few years.
The field doesn’t have the best drainage, and the compacted permanent paths were completely infested with quack

After after fall plowing, we’ve taken advantage of the dry spring and have disced the field 3 times already, plus 1 pass through with a riding cultivator set up for field cultivation as best we could (Our springtooth was hit by an idiot with a truck last year.)

The disc harrow has been working, though only slowly, as the grass hasn’t had a chance to regrow much.I liked the action of our S-tine sweeps on the cultivator, but we didn’t like the way we had the cultivator set up.
I think we need at least another 2 months of fallow to kill it. Then we’ll plant buckwheat, or another fast-growing cover crop, just for good measure. I really hope that this is a 1-time affair, as 14 weeks of fallow and intensive cultivation doesn’t fit too well with the ideas that I have about soil health.

As I understand it (not that well), quackgrass should be disced during spring fallow, so as to fragment and destroy its food reserves, while it should be desiccated during summer fallow. If it is disced in the summer, it is more likely to multiply.

And my feeling is that zero tolerance is probably the best policy.

Ben Dube
Cerridewn Farm
Green Mountain College

[nihiljohn]

OK, I’ll get my head handed to me for this, but I’m going to point out the elephant on the table. Round up is the best selling herbicide in the world for one reason. It works. And with the patents off, the generics are cheap. And they work. Im not saying, I’m just saying.

[Andy Carson]

Thanks for all the thoughts and good insights. I think I am going to make a tool with wider sweeps. I have some C shanks that are taking up space in the garage and attaching wide sweeps and making a frame seems very do-able. I wondered if S tines would be more suitable, but I understand that part of thier advantage is in that they vibrate at speed. I think it is unlikely that my oxen are going to achieve the speeds required for this vibration. I also like that the s-tines would move around rocks, but as the ground is already broken up, it is likely that the rocks will move around the tines (rather than the other way). I am planning on 7 or 9 shanks with 8 inch sweeps set up in a V pattern with a 2 inch overlap. I’ll probably run them at a depth of 2 inches, and a total width of 4-4.5 feet. I suspect this tool will pull somewhat harder than a springtooth or equal width, which is why I am planning narrower tool than the springtooth my team is pulling. It is also pretty easy to take off shanks to adjust width. I am pretty happy with how much ground I can cover with a 4 foot wide implement, and suspect I will rarely make anything much wider.

I think that if I was growing vegetables, it makes sense that I should have zero weed tolerance. With field crops, though, I think some level of weed tolerance is appropriate. Not saying it’s OK to have lots of weeds, but zero is a tall order without chemicals.

By the way, I hear you about the roundup, nihiljohn. I am not going to say you are wrong or crazy in any way. The problem is using chemicals removes all the work I have done following organic practices. Truthfully, I don’t like the concept of roundup-ing a whole field, but I believe it is also a strategic mistake in my situation. If I use the chemical practices of a “big ag,” it puts me and wahtever I grow on equal footing with them. If I am going to spray, why not use chemical fertilizer? Why not plant genetically modified corn? Why not use tractors for all my work? If I did all this I would be surrounded by competition by conventional farmers throwing chemicals at thier problems and it would devalue my products a lot. It is just so easy to produce a crop when you jsut throw herbicides and chemical fertilizers at the problem. If I started to follow conventional proctices, the main thing that would differentiate me from the competition is that I work a lot less land. When conventional farmers struggle to turn a profit with hundreds or even thousands of acres, it’s easy to imagine where a 5 acre conventional venture growing field crops is going to end up… I feel it is important strategically to differentiate myself from conventional farmers in a meaningful and philosophically justifiable way. I believe following organic principles and using draft animal power is a good way to do this. In truth, part of this choice was dictated by personal preferance, but I think it does makes sense too.

[Tim Harrigan]

Here is a picture that I snatched off the HPD site that looks like Triple-K style tines with rolling harrows front and rear. In plowed ground so weed control is hard to assess.

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