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gamebird

Preserving soil structure vs. digging in organic matter

gamebird
17 years ago

So which is more important:

Preserving soil structure or digging organic matter into the soil?

My situation is this - in October I finished desodding a new 100 square foot section of lawn to make into vegetable garden. This will approximately double my tiny garden area. We dug down about 12 inches and turned the soil, then added about 4 inches of leaves. In the spring, I'll have some compost to add to it. Should I dig the compost into the beds? Or just scatter it on top like a mulch?

What would promote vegetable growth the most?

Comments (56)

  • gardengal48 (PNW Z8/9)
    17 years ago

    LOL, Donn!! I am not against the use of machines (I've been known to use a Mantis a few times myself), just the overuse of them. Like a number of things in gardening, some folks think that if a little is good, a whole lot more is a whole lot better and wind up pulverizing the soil with repeated use. And that's pretty close to impossible to do with handtools.

    But you're right, a couple of passes with a Mantis and you have a workable planting bed in pretty short order.

  • greenj1
    17 years ago

    re: "Worms hate 'em, but they can be warned in advance, and they adjust well."

    How do you notify them -- email? posted notices? midnight knock on the door?

  • donn_
    17 years ago

    I usually pin a notice on their bulletin board. ;>)

    Seriously..make a ruckus on the area you're going to till, and start off with a few very shallow passes, and they'll start moving down and out to avoid the work.

  • heptacodium
    17 years ago

    May I ask question?

  • pablo_nh
    17 years ago

    "May I ask question?"

    During your rebuttal period :)

    How's this for a compromise? Core aeration, then spread compost. You get some in the soil, without actually tilling it all up. I've had pretty darned good results on my lawn. Haven't needed it in the garden.

  • bpgreen
    17 years ago

    "Seriously..make a ruckus on the area you're going to till, and start off with a few very shallow passes, and they'll start moving down and out to avoid the work."

    A lot of people are the same way :)

  • donn_
    17 years ago

    So true, bp.

    7-Son...feel free! We await your inquiry.

  • heptacodium
    17 years ago

    My question is this:

    Why is it so generally assumed that altering soil structure is
    a) easy or b) bad?

  • gardengal48 (PNW Z8/9)
    17 years ago

    Soil structure determines the way soil particles are bound together = peds. The peds (aggregates), their sizes, the way they fit together and the spaces between them determines how well soil drains, how oxygen is able to penetrate down into the root zone, how easily roots are able to spread and how friable or compacted the soil is. Excessive tilling, as well as working the soil when it is overly wet, breaks up the peds and makes them smaller and more uniform. The smaller and more uniform they are, the less pore space. The less pore space, the poorer the drainage, the less oxygen and the more easily compacted the soil is.

    Once the peds are broken down, they do not reform easily.

  • lakedallasmary
    17 years ago

    Worms will move organic matter down. That is the way nature does it.

    I no longer remove sod. Put enough mulch and sod turns into humus and very nice humus at that.

    Plus I have noticed plants seems to grow better in the presence of grass anyway. Keeps the soil cooler for one thing (a needed thing in Texas!)

    Nature does not till up soil to plant new things. Never! But in nature the squirrels do not scrape all the top soil and sell it, laving nothing but clay.

  • dchall_san_antonio
    17 years ago

    That's a great description gardengal48. It reminded me of the situation on most farms and ranches. When livestock drink from a stream or pond, their feet sink in at the water's edge ruining any soil structure that might have been there. Ranchers refer to the soil as "pugged." This makes that soil at the water's edge very hard to grow plants in. When ranchers fence off the natural water sources (usually mud holes) and pipe water to troughs, the mud holes return to clear fishing holes with increased stream flow from the improved soil structure supporting plants and filtering roots.

    If the livestock are on a pasture after a hard or prolonged rain, they will ruin the pasture for grass for at least six months and often more than a year depending on how the owner reclaims it.

    Another problem with soil structure in open fields is rain falling on bare dirt. The impact of the raindrops will destroy soil structure. Ranchers that realize this will ensure they have grass growing from fence to fence to absorb the impact of the rain before it hits the soil.

  • heptacodium
    17 years ago

    OK, who here REALLY believes nature does not till the soil? Can anyone provide an example of natural systems acting in a manner capable of providing a perfectly efficient tillage methodology?

    I can. See above posting.

    Again, why would it be considered bad to alter soil structure?

    Let us assume I have a sandy soil. I add organic matter with the intent of increasing fertiity and water holding capacity. Is that bad?

    Or a clay soil. I add organic matter to make it more porous. Is that in and of itself bad?

    I'm not talking about giving up my day job or calling in sick when it rains so I can till my ground incessantly in the worst weather conditions to do the job. Actually, when the soil is that wet, I'm not in the field...unless the cows get out, but that's another can of worms.

    I'm also not talking about utilizing soil as an engineering medium. I'm talking about using the soil as a component of an agricultural system, where plants are grown to maximize yield to provide food. You can do this on 50 square feet, or 350 acres. If my natural soil structure is a blocky type, would not a crumbly type be better?

    We are also not talking about simply running the tiller in the ground, never adding anything to what we are tilling. We are talking about using tillage (be it PTO powered, a self powered walk behind tiller, or a shovel) as a means of adding stuff to that ground. I fail to see how adding a decent volume of (relatively) course, porous material is going to destroy soil structure. If anything, I would propose the opposite point of view.

    I'm also not talking about what conceivably could happen. I could conceivably grow the world's largest tomato next year. I could win the lottery. Not betting on either one. Thousands, millions of people till in one fashion or another a few or several times a year, and this has been done, in one fashion or another, for quite a few years. Of all these instances, how many actually achieve total degradation of soil structure?

  • donn_
    17 years ago

    "Again, why would it be considered bad to alter soil structure?

    Let us assume I have a sandy soil. I add organic matter with the intent of increasing fertiity and water holding capacity. Is that bad?

    Or a clay soil. I add organic matter to make it more porous. Is that in and of itself bad? "

    Neither of those practices would be considered bad, and I don't think anyone has said that altering soil structure is automatically bad. If your soil's structure is bad to begin with, why wouldn't you amend it for it's benefit?

    The consensus seems to be when adequate soil structure has been achieved, by whatever means, excessive tillage can harm that structure.

  • happyday
    17 years ago

    I've been told that if you dont till once a year, rain and freeze/thaw and weight of soil and walking on the soil will compact the soil to where nothing grows but weeds and grass.

  • dchall_san_antonio
    17 years ago

    heptacodium: Was there something in GardenGal's explanation of ruining the soil structure that didn't make sense? Nature does not do mass plowing. I've mentioned this before: if She wanted plowing to be the norm, she would have covered the Earth with tens of millions of pigs instead of cattle, horses, antelope, deer, buffalo, goats, elephants, camels, llama, and sheep.

    I've been told that if you don't till once a year, rain and freeze/thaw and weight of soil and walking on the soil will compact the soil to where nothing grows but weeds and grass.

    Not at all. I know of a group of cotton farmers in the Texas Panhandle who have not plowed in years. They also do not irrigate because they don't have to. When it rains up there, their soil retains the moisture much longer, because their soil is full of fungus that retains moisture. Annual plowing breaks the fungal strands and kills it. I've seen pictures of the tilled cotton lying limp on the ground from drought while the no-till (and no irrigation) cotton sits perky and fresh not 30 feet away. And I believe Penn State tested the concept with corn. Can anyone verify that? I'm still looking for that - I've seen pictures but nothing written.

  • Lloyd
    17 years ago

    Once again there appears to be a confusion between terms.

    Plow; Till; Dig-in; Cultivate; Roto-till; Roto-vate; Harrow; Disturb; Disc; Deep Till etc etc.

    These are not interchangeable words. Each is different, some to a great extent. I'm thinking there should be a definition of each and people have to clearly use the one they mean. As an example, dchall quotes happyday using the word "till" but then uses the word "plow" to compare it to and then proceeds to use "tilled" in the same paragraph. These are different methods. I realize some may be using the generic term "till" but others may be more specific in what they mean. Or maybe they don't even know what they mean.

    Lloyd

    Here is a link that might be useful: Some farm terms

  • happyday
    17 years ago

    Nature does not do mass plowing. I've mentioned this before: if She wanted plowing to be the norm,

    Yabut the natural norm wild versions of the fruit and veg we like are much runtier. You dont find big fat juicy 2 pound tomatos growing wild on the prairie, etc. Our big juicy corn cobs are bred by indigenous people from a grass grain. The wild forms of all the fruit and veg we like would be a big disappointment if we ordered seeds and the wild forms grew.

    I'd like more information on this Panhandle fungus claim. Has this been proven? What is the fungus called? Is the fungus for sale as innoculant? Seems like everyone on dry land would want it.

    I have also heard the cotton will establish as a perennial small tree (not cottonwood) in Texas if not cut down, and that because of this and to prevent perennial cotton overwintering the boll weevil, it is the law in Texas that all cotton plants must be cut down after harvest. Anyone have knowledge of this?

  • donn_
    17 years ago

    There is no one rule,
    To serve all garden purpose.
    Do what is needed.

  • esther_opal
    17 years ago

    Donn, how do you know what to do if there are no rules or maybe a better word would be references for opinions.

    Gardengal, ped is short for what? And, what holds whatever they are together?

    Lloyd, Tks, interesting the farm terms reference.

    dchall, I have heard of a cattle farmer who swears by improving the soil by improving soil biology, she was called called the big bull lady or something like that. Do you know anything about her. no reference

    I did notice that Kimmsr gave reference to "soil food web", seems there is lot on the web about that, will be reading a lot!

    I've read many different opinions that seem to conflict on this thread.

  • donn_
    17 years ago

    e_o..I didn't say there are no rules. I said there is no one rule.

  • gardengal48 (PNW Z8/9)
    17 years ago

    Ped isn't short for anything. It is a term geologists and soils engineers used to refer to a natural soil aggregate. The aggregates are held together by their own chemistry and also by the activities of soil organisms that secrete adhesive-like substances. That is why the encouraging of soil biology also encourages the development of soil tilth.

    heptacodium, I don't see where anyone has stated that altering soil structure is bad - quite the opposite. One can improve soil structure to a significant degree and I'm sure 99% of the posters on this forum can attest to that. But you can also degrade soil structure to an equally significant degree and excessive tilling (and "tilling" is generally defined simply as cultivating the soil) is one sure way of achieving this. And it is far harder to remediate a degraded soil structure than it is to simply improve one that is less desirable than you'd like.

    There's quite a lot of science behind this - I'm not making this up :-) Yes, it is far more likely for soil structure degradation to occur in a large scale agricultural enterprise than it is in your home garden but over-eager or over-frequent tilling can occur anywhere. One of the more common aspects of this in a home garden situation is the development of a hardpan layer immediately below the looser, tilled earth. The other two very common results are the loss of organic matter from frequent tilling (the more you turn it into the soil, the faster it decomposes) and the loss due to disturbance of soil biology.

  • lou_spicewood_tx
    17 years ago

    Happyday-

    Google mycorrhizal fungi.

  • heptacodium
    17 years ago

    dschall...hmmm...yes, nature DOES till, even on a large scale.

    Perhaps not as dramatically as a farmer pulling a put-put out of the shed, hooking up to a implement of indeterminate origin, sticking a chaw of chewin' tobaccy in his cheeks and proclaiming loudly for all to hear, "This is how my pappy did it; if it was good enough for him, it was good enough for me."

    She allows a herd of large land mammals to graze. The end result is just as effective. Not now that the impressively large herds of bison are gone, but saying she didn't...not gonna get into it.

    Also, where I live, the farmers went through the no-till stage. They are back to ploughing annually. Among other things, ploughing cuts down on plant debris in the field, which cuts down on harboring sources for inoculum of insect and disease pests for the following year. In our case, ploughing equals fewer chemicals, which is viewed as a more than acceptable tradeoff. However, rather than any irrational fear of chemicals or political basis, it's financial: It's cheaper to plow. The rest is just gravy.

    We can also trade case-files until we are blue in the face. All we will prove is that there are a lot of case files to peruse, and a lot of equally successful methodologies. Not saying one is right, one is wrong, just that many are successful, and if successful, has something of value to be shared. However, we live in a world of choices. By making one, you exclude others (yes, we live in a world where discrimination is not only practiced, it is in most cases encouraged).

    gardengal, you gave a very good definition. Actually, you did a better job of explaining it than the lab instructor I had when I took soils classes in college. Kudos.

    And yes, I am fully aware of the science going into this. Really.
    ------------------------------------------------------
    Here is the crux of why I asked my question in the first place:

    If is it generally considered good to till in the organic matter in the first place, why can't we just say that?

    When it comes to soil, all I have learned is this: Of all the factors involved in growing plants, the most complex is soil. It is also by far the least understood, which can be attested to by how hard it is to answer the simple question intially posed here.

  • pablo_nh
    17 years ago

    "If is it generally considered good to till in the organic matter in the first place, why can't we just say that? "

    I guess because it depends on your soil, what you're growing, whether you have raised beds or not, how much OM you can spare to put in, personal opinion and experience, climate...

    I'm growing in raised beds that are mostly OM, on compacted sand and gravel base. Other parts of the yard are typical acidic New England sandy soil that's only a couple inches deep before you hit straight sand in some places. I'm growing a little grass, some clover, and weeds. The flower beds are a bit different. What I tell you works for me is probably not going to work as a universal recommendation.

  • steve2416
    17 years ago

    Let me weigh in with my two cents: It's fun to till! I have about a 1/3 acre garden. I use 1/2 of that each year and cover crop the other and sometimes lug in a couple of PU truckloads of free horse manure. My crops benefit friends, family, and a local church. There is nothing more fun than attacking a shoulder high stand of Rye and Austrian Field Peas with a 15 year old 3hp Troybuilt Pony. Takes forever (original tines) and the earthworms have ample warning to dive.
    At 58, my big boy toys are a lot of fun!
    Steve

  • happyday
    17 years ago

    Lou, was there a specific link, point, thought or idea you wished to convey that might narrow down the field? seeing as how "mycorrhizal fungi" alone results in 719,000 ghits?

  • lou_spicewood_tx
    17 years ago

    Yep. That's how important they are. Read them through like I did...

  • happyday
    17 years ago

    Why dont you sum them all up for us here?

  • lou_spicewood_tx
    17 years ago

    They help plants thrive. It has been discussed many times in the forums. Do a search. Most of them aleady know what MF is anyway.

  • bfreeman_sunset20
    17 years ago

    The no till soil web method makes sense, but it didnt work for me. I finally tried it this fall, left the summer crops roots in ground, and compost layer I used as mulch around plants. My plants were stunted and didnt produce before frost. Wont try it again. I think the added air and tilth is needed for my plants. I theorize it is my arid location that makes it not work. Drip irrigating with hard water, just not good with a more compacted soil. I do have a sandy soil.

  • Kimmsr
    17 years ago

    Charles Darwin estimated that earthworms would turn over the average gardens soil once every 6 years. Simply because Ma Nature sees to it that your soil is turned periodically is not a good reason for you do do that every year.

    Here is a link that might be useful: Soil structure

  • gonefishin
    17 years ago

    I agree with bfreeman and also what Kristi (Remuda1) said in another thread on the same subject, that she had never seen a time where the strcture of her soil had not been improved by tilling it. You can probably see a few small plants {{gwi:320462}} in this picture where the broadleaf mustard greens in the "no tilled" area bordering the garden on the left are pretty pittiful in comparrison to those in the row to the right of the mulched potato row, which has had the normal amount of tilling and ammending. I have a number of other pictures, most probably more graphic and make a better comparrison.

    My need to till has diminished over the years because the tilling, plowing and ammending has built some great soil and eliminated most all unwanted weeds and grass. Heavy mulch of shredded oak leaves after the plants are up tall enough takes care of the rest.

    The no till bunch are passionate in their belief that is the way to go. I think that is based in a large part on their own experience of planting in raised beds, lasagna beds etc. which are basically a contained compost pile suitable for a limited area but not necessarily what would be practical for my garden, and certainly not a large field.

    Some of the stuff I have read above is bunk in my opinion, a cotton plant would not become a perinneal in the Texas pan handle where low temperatures would kill them early in the fall of the year, and all the stuff about what has happened over eons in the amazon and ukraine may make for interesting reading and heated debate, but has little relationship to my garden in the back yard.
    That is just my .02 and at my age, I will probably live out what ever is left of my lifetime going with the things that a lifetime have taught me on a first hand and personal basis. If I were struggeling with trying to raise things, then I might be looking for different things to improve it, but I am quite happy with the way things grow there now.
    Bill P.

  • donn_
    17 years ago

    Happy...Wikipedia has a good "executive summary" on the subject.

    Here is a link that might be useful: Wiki on MF

  • gamebird
    Original Author
    17 years ago

    Well, thanks all for the very different opinions! The reason I posted was because I'd seen one thread here and another there putting forward different points of view on it.

    In my case I'm using a shovel and have no intention of buying a Mantis or other mechanical tool (I have no safe place to store it). What I take from all of the above is that I'm unlikely to do any harm by digging in the compost in the spring using a shovel - and this would be a better approach than scattering it on top.

    Again, thanks for the information!

  • esther_opal
    17 years ago

    The only thing Oral Roberts ever said that impressed me was "a man convinced against his will is of the same opinion still".

  • happyday
    17 years ago

    Esther, that statement is very true.

    Thanks to those who offered basic info on mycorrhizal fungi, but I was asking for verification on the specific claim dchall made of a group of cotton farmers in the Texas Panhandle who have not plowed in years.

    I'm sure MF is beneficial, I just doubt that the only way to get the benefits is to never till. I doubt that tilling kills all MF permanently, as seems to be suggested. I think untilled fields would become compacted due to rainfall, soil weight and in this case, planting and harvesting heavy equipment rolling over the fields. I think compacted soil is not as good for domesticated crops as tilled soil. I doubt that MF works so wonderfully that a non-tilled field would never need or even benefit from irrigation. MF is probably ubiquitous, that is, it is everywhere, and will grow whereever the host plant is. So it isnt as if there is a rare strain of MF that can be confined to a no till field that would turn cotton into a wonderplant that will thrive where other cotton wont, but only if the field is never tilled. Cotton can do well in droughty conditions. It was domesticated separatly in India and South American thousands of years ago(pops).
    I suspect many of these forum disagreements are faith based arguements, that is, some people choose to put their faith in no-till, or organic, or what have you, and that is their right, this is a free country, but evidence based on reason can be presented to show them other options. With any choice there are associated tradeoffs.

    I'll answer my own cotton questions, in case anyone is interested, yes, cotton is a perennial plant grown as an annual(pops) in the US and yes, there is an Texas Boll Weevil Eradication Program(pops) that the Texas Legislature has voted on, which does include plow up dates and stalk destruction, as the weevil can overwinter in dead plant material, but it is more complicated than my friends from South Texas had told me. For instance, Texas is divided into 17 zones(pops)

  • esther_opal
    17 years ago

    happyday, I don't have the reference but in one of my searches on MF I found the statement that tilling sets MF back a year.

  • esther_opal
    17 years ago

    I am a faith based gardener, I have faith that I was given an intellect and if I don't understand the information I come across then I have faith that I will now do well.
    I further have faith that by grace I will be forgiven my foolishness.

  • pablo_nh
    17 years ago

    Of course everyone needs to till every year to grow anything where you get a freeze/thaw.

    Why do you think that people till their lawns every year? :)

  • happyday
    17 years ago

    One of those articles mentioned highly erodible soils. In some cases such as hillsides or high wind areas I would agree that tilling should be kept to a minimum or cover crops replanted ASAP.

    Meanwhile, the first 5 links all mention leaving crop residue as a component of no-till (though the Arizona one does mention wheat straw). The boll weevil has only been eliminated from these states by eradication programs that include removal of overwintering materials. If they start leaving cotton crop residue out again, they may well get re-infested.

    Might be better to mulch the crops with vegetable matter of other plants. But I suspect some of these attempts might be money saving measures, possibly due to the increased cost of diesel to run tilling equipment. So gathering and spreading other vegetable materials as mulch might not be cost effective.

    There is also repeated mention of herbicides. Personally I'd rather till than spread herbicide. Guess I have little faith in the safety of herbicides.

    Since these no-till efforts are in the ambitious beginning stages, not yet established as mainstream practices with obvious benefits to all growers, I would suggest that yes, there may be an element of faith involved.

  • happyday
    17 years ago

    Pablo, thats just the point. Grass and weeds grow well in untilled soil, domesticated food crops, not so much.

    Let me know when your tomatos, beans and squash start moving into and out-competing your lawn, k? Thankz bye!

    Esther, you sure were right with that Oral Roberts quote! :)

  • donn_
    17 years ago

    "..I suspect some of these attempts might be money saving measures, possibly due to the increased cost of diesel to run tilling equipment."

    Spoze? You mean these cotton farmers are profit motive driven? Fancy that.

  • bfreeman_sunset20
    17 years ago

    I forgot to mention. Here in the southwest the soil is turned ravenously by pocket gophers. I know in one wildflower preserve they irradicated these types of pests trying to help. But they found that the California Poppies liked to grow in this disturbed soil, and they were disappearing without gophers.

  • shrubs_n_bulbs
    17 years ago

    I'm waiting to see someone grow potatoes without disturbing the soil :)

  • adirondackgardener
    17 years ago

    Well, shrubs, I don't disturb the soil much with my method of growing potatoes. I simply lay the seed potatoes on the surface and cover with mulch, usually chopped leaves. Harvesting involves pulling the mulch off and picking up the spuds.

    Having said that, while Ma Nature doesn't get out there with her 6 HP Troy-Bilt tiller, I don't see her growing much in the way of eggplant, peppers and tomatoes out in the wild either. I wonder why that is?

    I'm in favor of a program of limited tilling when it is necessary. When is it necessary? Every garden or field will be different but if the difference is not tilling and waiting years for the earthworms to do their thing so I can grow a carrot or getting organic matter into the soil and crops off it in the same year, then some form of tilling is the way to go for me.

    I double dig most of my raised garden beds. The disturbance of the soil structure seems to have little to no visible negative effects and I for one am not alarmed at harming the mycorrhizal fungi. Nor am I going to avoid tilling when it will benefit me in order to avoid injuring the earthworms. (Earthworms, which as noted in other threads, are noxious invaders of this northern forest I call home.) Nor will I rely soley on methods Ma Nature uses to build soil, since in my limited years left on the planet and my need to feed myself during those years, I recognize that Ma Nature has had approximately a 10,000 year head start on me in the soil-building department.

    Wayne

  • esther_opal
    17 years ago

    Wayne do you start with fresh soil each year for your garden?

  • adirondackgardener
    17 years ago

    >Wayne do you start with fresh soil each year for your garden?

    Only when expanding by creating new beds. Otherwise I may just loosen the top couple of inches of a previously double-dug bed with a rake or light-weight hoe before planting. Carrots always go in a freshly double-dug bed whether a previously planted bed or a fresh, new one. Lots of mulch, except when warming the soil in spring & early summer helps feed the soil in a no-till manner.

    Since I recently moved away from my last garden, next year will be a totally fresh start over in Maine, unless I find a place with an existing garden.

    Wayne

  • vera_eastern_wa
    17 years ago

    Pablo...

    I get a freeze/thaw every year and have NEVER tilled anything! I only need double dig the veg bed while applying rabbit manure/pee soaked bedding. Periodically thru-out the season I apply rabbit manure and more straw on the surface. The mixed boarder beds were double dug once and each year I add more plants just by digging a hole and plopping it in. The majority of my garden plants are drought tolerant and prefer ugly infertile soils and therefore are grouped together. Other beds are filled with plants that get compost/mulching.

    I have a nice garden :D

    Vera

  • pablo_nh
    17 years ago

    Vera- yup. That's what I was saying as well. I don't have clay, however, and I'm not so silly as to ever walk on my garden beds (a big ole No-No in my book).