Science doesn't count, or at least can't be taken too seriously unless the results can be verified. For example, "temperature vs germination rate" on some seeds, we probably can verify reasonably easy. But "soil amendment vs long term root systems", we probably had trouble verifying it. For a starter, what do we mean by a good root system? Is it by our intuitions, or do we have a commonly agreeable guage that one can compare the quality of root systems? Without more precise definition, any statement concerning the quality of root system can not be meaningful scientifically. Another things, how do we test or examine the root systems? Are we to dig them up in a few years, and again in another few years? And how big a sample do we need to work on to make the study more convincing? These are basic and necessary questiions to be answered. THere are way too many factors involved in the growing of a young tree, many factors are also intertaned. That's why I said for a backyard gardeners, it is more of an art than science. This doesn't mean we should ignore the scientific results, but we should not be too sticky with any study based on some or a few idealized factors.

Harvestman,

The reason I'm addressing backfill is because that seems to me to be what the OP was talking about. If the discussion was addressing the soil over a large area, there would be no need to consider the roots expanding out into native soil. Many of the concerns would still apply even if we were talking about amending an entire field (to a limited depth), but of course some would not.

As to my talking more from theory than field experience, that seems to me to be an invalid concern. First, I am indeed blending my personal experience with scientific findings, but that only strengthens their validity. When large scientific studies/tests are done, using proper scientific controls and taking into consideration all the perceived variables, the results should have tremendous weight compared to one individuals perception of their limited experience. An individual's experience is important (especially to them), but it rarely trumps or makes less valuable the results from properly conducted scientific studies. If I was only reporting my own personal experiences, I wouldn't expect anyone to put much weight into what I was saying.
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Windfall_rob,

I'll only address two comments you made that addressed things I had said, and let the rest of the posts speak for themselves.

First I think your sand and gravel analogy is much less clear than my use of the sponge and gravel. While, to a lesser degree, the sand would wick water away from the rock just as a sponge would, the sand would not approximate a finer particle soil such as clay, silt, or loam as well as the sponge would. The analogy has it's limits, as all analogies do, but I used this example for better visualization.

Lastly, I wanted to address the mulch versus drainage issue. Yes, as I noted earlier, mulch can help. However the large net water loss due to drainage may, in many cases, be much greater than water loss to evaporation. A limited moisture conservation from mulch may not make up for a significant loss through soil wicking.
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Annie-lee,

From your comments, you seem unfamiliar with scientific method. Addressing concerns similar to the ones you made is what scientific studies are all about!! When we look at large studies conducted by major universities and professional scientists, we're not working with middle-school science fair projects. Often, many acres and many sites are employed. Thousands of plants may be involved and the results may be studied over many many years or even decades. Saying, "Science doesn't count" is really saying "Reason and careful observation doesn't count."

annie-lee, OK, I know my comment about you gardening by gut feeling was presumptious, (and I apolagize) but have you looked at the Carl Whitcomb research on the issue of adding amendments to planting holes? Look at some of the specific research and we can discuss that.

I will say this, Carl Whitcomb's and other research I've seen didn't involve stable (not as in horse stable but broken down to humus) compost, so some of the problems were certainly due to tied up nutrients.

I have seen gardens where mellowed horse stable waste that still had lots of recognizable wood shavings in the mix were incorporated into the soil. Even though the stable waste presumably has a good ratio of N to carbohydrate the rapid break down of the wood when the stuff is incorporated seems to consistently stunt vegetable growth. It doesn't happen when you let the stable waste break down "completely" before incorporation.

Often the amendment in the experiments are unstable forms of organic matter like peat moss. I'm actually going to google around right now and see if I can find any experiments that involved using humus, but the logic that messing with the soils texture right around the root ball is more likely to do harm then good resonates with me- call it a gut feeling if you want.

Yes, all three of my posts were poorly written. In part because I was trying to express complicated ideas in a short span and in part because every time my two year old sees me sit at the computer things get ugly...but I see now that they are difficult to understand at best and could even come across as haughty or rude...certainly not the intent.

My comments on pore size were meant more to try to flesh out the wicking process a bit. It is not easy to do in short form, and perhaps Brandon has done it better in the past. But essentially wicking/capillary action is driven by attractive forces at the molecular level between water molecules and surfaces they encounter. Finer pore size equates to greater surface area and a more powerful tendency to "draw" water away from reservoir...in this case a larger water filled pore. This all gets complicated by the fact that these intermolecular forces vary dramatically from material to material (hydrophobic/ hyrdraphilic)....so we need to be careful with saying things like finer soil will wick water from coarser soil...that is certainly true if the particles are composed of the same base material, but may not be true when they are not.

Hydration is different. It occurs when water is actually inserted into the molecular structure. Minerals do this, but mostly on a long term basis that can only be reversed under extremes of pressure or temp. (clays being an exception). Many long chain organic compounds also do this, but they will absorb and release more readily to reach and equilibrium with their environment. Essentially the water is less tightly bound.

I know fungi and bacteria as well as alga can utilize this bound water in organics to survive...to be honest I do not know for fact that plants can do so directly (suspect they can. Even if they cannot it is still considered a portion of the water holding capacity of the "soil"

As to my background: I am a complete amateur in terms of horticulture...but trying very hard to learn, as it has become a real passion.It is something I always dabbled in but didn't have an opportunity to really explore until 5 years ago when we finally settled on some land...even now I look back at the first few years and shake my head at the things I did...hopefully I will look back on the present with less disdain.I have read a lot more, lurked on this forum quite a bit, and tried to pump local pros for info at every oportunity; and it has been most helpful.

Fortunately for me (because it makes it easier to learn this stuff) I have a very strong background in the sciences. I trained as an environmental scientist while at university. Those places are expensive so I took the opportunity to take the equivalent of 130% credit load the last three years and got an extra years worth of learning for free!..as well as getting involved in all the field research I could. Hydraulogy, Sedimentology, Botany, geology,ecology, soil microbiology(wish there had been more of this), geochemistry,ect. That was my mental meat and potatoes for some time.
Unfortunately the more educated I become about the planet and what was happening to it the more depressed I became I just couldn't follow a career where I woke up every day to either "chronicle the great decline" or fight a losing fight. So I walked away 15 years ago and became a traditional boatbuilder.
But if your a scientist you can't change, it's just they way you explore your world. So I try to keep up and apply that knowledge and experience to what I do.

That said I should take a moment and apologize to the original poster for this side track of an introduction to me..I should probably introduced myself in a separate thread when I came out of lurker mode this fall. This has been a great place to learn and I hope to be able to contribute as my horticultural effort/experiments begin to bear fruit (sorry couldn't resist).

http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=2692&Type=2

I guess I found what I was looking for right here with the first quick search.

"Science doesn't count" is really saying "Reason and careful observation doesn't count."

Reason is of course very important, but the troubles with reason without verifications is that we may have wrong or insufficient assumptions in the first place. That's why we had seen many scientific results being modified, some are contradictory to each others. Observations can be sujectives without setting a well defined measurement, such as what I asked: a guage to measure the quality of root systems.

The gauge to measure the root system is how quickly the establishing tree grows. It is no mystery that a tree that comes out of transplantation with greater vigor is the one most likely to survive and in the case of fruit trees bear useful crops sooner.

It is the top that will generally control the vigor of the root system and will trigger adequate root vigor to support the top in a healthy tree. You can't have a vigorous tree without a healthy root system.

Rob, I think what you say about capillary pull is too cautious. The clay is never of the same mineral composition of the coarser layers in any existing soil, as I understand it (softer minerals powderize more easily), but the capillary issue is very consistent regardless. You'll never find a shallow layer of silt over sand and not have a drainage issue in my experience. Ever seen it happen?

As far as the original poster, it think the question has been answered so no harm is done by continuing the conversation here IMO.

When reading and taking on board everyones point of view. I think that 2 points relevant would be the size of the bush and the length they are in the ground. Fruit trees are not fruit bushes and to treat them with a one size fits all methodology would be incorrect. Indeed I'd suggest that even the rootstock would make a difference (possibly more of a difference).

One thing I would like to see is the effect of the opposite experiment ie. Deliberatly putting it in a 'hole' of bad soil.

I actually think it's just one of those bits of 'useless' research in a way because the only true way is to see what works for you, your land, and the particular plant in question and that's one thing no research in the world can tell you (and indeed no forum) :0)

But I'm still on my 1st year, so what do I know, lol. Interesting though....

MadF Yeah, that makes sense to me, I use the same concept when treating my own sickness- screw those scientists- my body isn't like anyone else's anyway. I've got a bad sore throat and I saw some interesting mushrooms out under one of my trees- maybe that'll do the trick.

Experiments adding amendments to back fill have been done with a wide range of species but if you want to do your own experiments be sure you have a control.

Annie-lee
In my opinion any scientist who isn't willing to throw out there theories and/or assumptions when presented with contradictory or compelling evidence has lost their way. Nonetheless if we want to attempt to understand our world we have to start somewhere...even knowing that our initial thoughts may be misguided. That's why we look for repetition of results and try to isolate variables....test and retest...anomalous results are often the most enlightening. Base lines are difficult in nature that is absolutely true, but difficulty shouldn't be enough reason to say it can't be done.
That said, I have known folks who have the "green thumb" some of them would throw their hands up at this whole discussion. when I ask them why they do something they can't really tell me why...it just seems like the right thing to do to them. They are far more successful than I hope to be. I respect what they do but it doesn't help me understand how I can improve myself.

Harvestman, I don't know what you mean by "too cautious"? I was trying to clarify my earlier and very poorly constructed comments. For me to transfer what I know into this new field (for me) I start with the most basic principles and try to build up: How does wicking work and what factors can influence it. I agree that they clays and fines are almost never the same as coarser material at an undisturbed site site; but we were talking about amending (disturbing) the site, and adding organics to the mix. so I was trying to play with what those variables might do to the equation.

The only situation I can think of where silt overlies sand and no drainage issues arise is in multiple thin bandings where you have silt/sand/gravel alternating for a significant depth. As can arise at mid-elevation stream banks/small valley floors. Even in these cases if silt is on the uppermost layer...things get mucky (poorly drained)

Brandon, Having reread the whole thread without the distraction of my children, I see that my understanding of your points was poor. I was indeed dismissive and rude in my responses and I do apologize. Clearly you have made careful study of this, and my lesson is not to try to have a detailed exchange while distracted and rushed.

Rob, I don't think you were rude, and I don't get easily offended. Harvestman has hardened me off. ROFL

I'm still laughing at his last post (and copying it so I can paste it back to him during our next debate, haha).

I'm just glad we have a place where multiple people can give input and those interested in gaining knowledge can do that. Many times I learn things from the very simplest posts or questions. Even if it's not the subject itself, addressing the subject will often bring up some new way of looking at something or even a new term that I haven't previously seen. I've even learn a little talking to Harvestman (-:

Harvest Man, I think you misunderstand me I don't mean that it's all non-sense, merely that that it's probably not the whole story.

To use a medical analogy as you seem to want to... I have a headache, the doctor gives me the 'recommended dose' of paracetamol, but is it the right dose. Only by taking it will I know it works or that I haven't taken enough... It's only his best guess as to what I need, and it may not even be the right thing, it maybe something else....

MadF. of course I was kidding, but I did feel your statement needed some clarification. Of course the practitioner will have to adjust to conditions on the field and the research only takes you so far.

Rob, what I meant by "too cautious" was only that when the textures are out of order you can generally count on problems whatever the more complex analysis.

Brandon, "I even learn a little talking to Harvestman", and "I'm still laughing at his post" to me these are rude snarky statements and seem like attempts at trying to gain unearned authority in the old pissing wars. I guess to you they seem like light jokes.

When I refer to you by name these days, I keep it positive and I certainly respect your input. Let's try to keep the high school out of this.

If you were offended by my statement about you speaking from research rather than experience, I'm sorry, but most of your input on this forum seems to me like you're playing the sheriff for horticultural research without ever a mention of your actual experience with fruit trees. This is a forum about fruit trees and home orcharding after all, and you seem to often give very little credit to actual experience.

Harvestman,

You take things way way way way way too seriously. Man, you need to seriously relax a little!!!!

I’ve decided to write a brief but fairly thorough explanation of how I think about amending soils with organic matter when installing orchards, something I do at about a dozen new sites a year as part of my business.

First, consider that in commercial fruit production organic matter is rarely brought to a site and trees are usually maintained in herbicide strips between sod strips. Sites are generally selected that have a deep soil with adequate drainage to begin with and new trees are planted without anything added besides mineral amendments. Traditionally in the northeast where I live orchards receive no irrigation and yet spring planted bare root trees almost always survive when planted in bare dirt.

Organic mulches are generally acknowledged to speed establishment but are considered too expensive and also too conducive to rodent issues to be used. Besides soil prep based on analysis, irrigation is the first recommended step to speed establishment.

Home orchards often are planted in sites less than optimum for fruit tree growth. Soils are often shallow and of poor quality and there is often extreme competition from nearby, very large forest trees. I seldom install an orchard where there are not roots from such trees in the soil mix. When holes are dug these roots are severed and can be presumed to grow rapidly in the disturbed and aerated soil where I install my fruit trees. This competition can be counted on to slow the establishment of a new orchard.

On the majority of orchards I install- and these are free-standing trees usually on 106, 7 or 111 rootstock, no irrigation is installed and I’m lucky if the trees receive more than a couple of supplementary waterings during their first growing season. Often they get no supplementary water- even on drought years. These are not whips I’m planting, but 4 or 5 year old bearing fruit trees. They are much more prone to stress than a 1-year whip. They die and I have to replace- they very seldom die.

Organic matter (OM) can increase a soils capacity to hold available water for plants and mulch will reduce water lost to evaporation. Some wood mulches also seem to store a sizable reservoir of water that presumably wicks into the layer beneath as it dries out. There are many other benefits of mulch that I won’t go into here.

My most common installation will include loosening soil well beyond the root ball in about a 5’ diameter circle to the depth of the root ball. If the soil is decent, I’ll add about 4 cubic feet of composted stable waste over several sheets of newspaper creating a 5’ diameter mulched circle.

If the soil’s kind of sucky I’ll add another 4 cubic’ of compost that is almost pure humus before spreading newspaper, and will plant the trees high to accommodate this. The newspaper and mulch is applied over this.

If the soil is extremely sucky (too shallow, completely devoid of OM- that sort of thing), I will add humus directly to the native soil, blending it well with the first few inches of native soil. I amend a fairly wide area- a 6-8' circle.

I do this before planting the trees and keep the top soil on top when planting. The quantity could be anything from 4 cubic feet to half a yard per tree. The half yard would be in cases where I’m creating mounds for each tree to improve drainage.

I sometimes have to trap out or poison rodents.

Because most of you won’t be transplanting larger, bearing age trees these efforts may not be necessary but I thought this might be helpful.

Harvestman,
Thank you for sharing. I can see that's very sound steps in installing a fruit bearing size trees. I should say, this is about what I normally do to transplant matured trees. Just one quick thing, and I hope this doesn't bring more controversal, there is one step I always do, but you didnot mention, that is: after back filling all the dirt, I always hold the tree and step my feet around the loose soil, to make sure the tree stand firm on its own and there was no air packets. I ususally water it immediately around the hole to make sure that any air packet is gone. I did that even when the soil is wet. May I add that after these many years, I always have good luck with my trees, other than issues with sun, etc. but not with soil mixing, or hole sizes, etc.

I do firm down the soil but without water, which is contraversal. Usually the proscribed method is to make sure soil is at a nice level of moistness before starting the planting process which I certainly agree with. But my feelings are air pockets are not a problem as I've seen where roots grow right through them so I just tamp down the moist soil enough to anchor the tree, most often stake (because of the size of the trees) and forget about additional water.

I like some air pockets, maybe just to be contrarian but if I had time I'd do a controlled study on the issue. I think it's another Whitcomb type research project waiting to be tried.

I think I do this as much because it isn't the proscribed method as anything, and seems to work just fine- but also when the moisture level is already perfect I figure why saturate. I don't expect anyone else to follow my lead, however.

If I'm planting a leafed out potted tree with the roots all in potting soil I'll saturate everything when I'm done and the pot before planting. I always saturate potting soil.

I should have mentioned in my previous post that in extremely sucky soil situations I incorporate, topdress with humus type compost and mulch with a less broken down form. I failed to note the last 2 steps.

I also should have mentioned that I also sometimes use wood chips- the free ones from arborists, as the top mulch. I prefer them aged a bit so they are rotten enough to hold extra water, but I take what I can get. My clients can easily absorb the price of hammered wood but I actually prefer chips if it's gone through a well serviced machine (no strips).

Hammered wood is fine for established trees as there tendency to matt makes them more weed repellent but it also create resistance to rain absorption.

Brandon, I do sometimes over react, but you should know by now that I'm sensitive to comments that seem to indicate that I'm some crank with no understanding of horticulture. That was one possible interpretation of your comments. This is my livelihood after all. I don't mind if you criticize my e-personality- I know it kindof sucks.

I really should learn to wait an hour when I get annoyed with one of your comments before firing off, I usually regret the tone and substance of my retaliations.

Annie-lee,

Using your foot to lightly firm the backfill and reduce air pockets is definitely a good idea. As mentioned, it may not be a great idea with moist soil (and that depends a lot on the soil type).

What I do is add about half the backfill soil dry, tamp it lightly with my foot, add the remaining backfill, and then use my foot again to tamp that down. In our mostly clay soil around here, tamping only after all backfill soil is added is not enough. One can excavate the soil after such a treatment and find that the lower soil was not affected by a single light tamping.

P.S.
To avoid possible confusion, I should probably replace the word "tamp" in the above statements with "lightly firm". I don't jump up and down on it.

Thanks, Brandon. Yeh, I agree that it involves more details in "firming" the soil around the tree. Usually, when you step around, you will find one side may be sinking in more than the other, or the tree was too deep, so you fill in more dirt on one side than the other, or push dirt underneath to raise the tree up a little. At the end the tree should stand firm and its soil surface should be roughly even with the nearbe surface, and I general will leave a slightly sloped disc to hold water better.
As far as air packet, I think it may not be a problem if one is vigilent and keep it watered during the first year. But if one plant it and let the nature take over, as Harvestman seemed to do so in his field, in more severe weather area and during dry spell, the roots inside the air packets could be badly "burned", I had seen this happened to my newly planted trees in Wisconsin years ago.

How do you know that roots were burned because of air pockets? When soil drys it has about the same affect as an air pocket, as fine roots die but structural roots have a waterproof sheaf that offers protection from dehydration.

I have often seen how roots plow right through air pockets in moist soil but never actually seen research that shows that soaking already ideally moist soil after transplanting bare root trees is beneficial. Moles here and and golphers out west produce much more air pockets than you'll ever leave after tamping down moist soil.

When I'm establishing annual plants on my property I often have to tamp down soil repeatedly because of the action of moles that love to harvest my ample earth worm population. I forget to do this until the plants stop growing. When I lived in the west I had to do this with establishing fruit trees because of golpher activity. Trees and annuals in this situation don't wilt or look stressed- they just stop growing.

I plant 100's of bare roots in my nursery and have never added water before or after planting- been doing it for decades. If watering speeded establishment I'm pretty sure I'd notice. Still if Brandon can find some research appropriate to my situation, I'm certainly interested. I wouldn't be surprised if research fell either way. But the research has to show that in the control the soil was at ideal moisture level.

Expert opinion usually sides with Brandon on this one though.

I almost understand some of the above technical discussion. But I know for sure that that no fruiting plant will grow in my native red clay. I rented an excavator and dug BIG holes for my fruit trees and replaced the clay with great soil that I had amended many years before- no appreciable organic material left. Then I took the removed clay and amended the hell out of it, gave it three years and put it in the next set of holes. Nobody around here is getting the results I am. There's an old joke about the difference between theory and reality. There's a UC Davis grad with a degree in permaculture nearby who talks a good show but can't grow jack. I feed my family.

Here's my saying, FWIW, about theory versus reality...

Questionable theory is when someone gets the idea that just because they see something, they think they understand what's happening.

Reality is what you get for results when a properly conducted scientific study takes place.

Amazing how often carefully conducted scientific studies produce delusion because of factors not fully understood. In horticulture the research is relatively limited compared to say, medicine, and medical research like all research is always in flux. One month the experts conclude something from one set of data- the next it's a different story.

There'd be more of this in horticulture if it was as well studied. As has been mentioned, the variables in horticulture make it pretty hard to really nail it.

Scientific research improves the odds greatly over total reliance on anecdotal observation, but don't be too confident about the meaning of a few studies.

Fruitback, maybe the reason what you did worked, and it doesn't surprise me at all that it did, is these basins don't tend to fill up with water because you get almost no rain during the growing season. Here in the east coast you'd probably have to plant those trees on mounds even after improving the soil. If the clay's reals hard, where's the water going to go when those basins fill up?

There are plenty of things in the horticulture world that aren't fully understood, but sometimes some people are so overly eager to dismiss or even deny what is fairly well proven, that it goes far beyond normal healthy questioning. I guess it's just typical human nature and certainly not limited to horticulture, but I still find it rather vexing at times.

Before I dug the big holes I dug small but deep holes and watched how they absorbed water all winter. Common sense has it's uses.

Brandon, so what do you make of fruitback's experience? Doesn't it contradict the researched wisdom about amending soil?

I just don't happen to believe that researched conclusions are absolute gospel and to use one of your expressions, need to be taken with a grain of salt.

"Doesn't it contradict the researched wisdom about amending soil?"

Not at all. There are multiple unknown variables in Fruithack's scenario, spanning everything from the assumptions, to the many impacting variables, to the way the scenario is compared to the theory, to the interpretation of results. Fruithack's success does not in any way negate the vast amount of research on the subject of amendment.

So what is the current thinking (or experiences) on using mycorrhizal fungus in the planting hole or worked into the topsoil around the plant? I have often scraped some of the fungus underneath the leaf mold around trees and added to the soil when starting plants.

These fungus are pretty much omnipresent and fairly non- species specific as I understand it except that prarie may not have the right fungus for forest species and vice versa (as I recall) and sterile soils will always benefit from innoculation.

I doubt what you're doing is helpful but can't hoit. At least you're not being snookered into buying the stuff.

Fruitback, if you're clay had decent drainage, how do you know if your trees didn't flourish just by virtue of loosening the soil which research certainly would endorse.

Do you think there is a nutritional deficiency in your soil that your amendments corrected? Did your amendments apprecibly alter your soils texture? What were they? Maybe it just doesn't matter because as long as you've solve the problem on your site it's all good.

I have to deal with a hundred different soils a season so it's hard to get by with just common sense.

Hman- You guys have totally lost me. Here's what I know and what I don't know. When my red clay soil is totally saturated I can barely get a shovel point into it. If a steel shovel can't penetrate, then roots can't either, other than the native brush and oaks. Digging the test holes with a post hole digger was not fun. I think the clay has plenty of nutrients. I totally grasp the concept of roots meeting the edge and turning in like a pot, so I dug holes about 8-10' wide by 4' deep, pushed the good soil in and mounded it up about a foot. Four years in I got cherries, nectarines, apples, and plums. Ten years in all are thriving except for the plum which died of canker. I've done variations of this with grapes, mulberries, figs, you name it. No problems so far, I'm eating fruit.

Harvestman: I imagine you already know what I'm writing about below, this is meant for the rest,I don't know about them.

Good research is that which follows the scientific method and is peer reviewed, hopefully in a reputable journal and accepted. What people do with the peer reviewed information past that is critical. Do they stand up and say a particular peer reviewed study is the end of the argument? Let's hope not, they'd be wrong and slamming the brakes on the scientific process. The delusion is not the result of good research but how people handle the results like saying it says one thing when it doesn't or saying it doesn't demonstrate something when it clearly does. Even some professors' have egos and turf to protect, I've seen it in action! To them I say, if you disagree, show me the research that supports your position and/or do the research that does and show me the results.

"One month the experts conclude something from one set of data- the next it's a different story." Maybe new research has come to light in the mean time, maybe the light bulb just came on. That's research in the biological sciences, nothing is set in stone.

"Scientific research improves the odds greatly over total reliance on anecdotal observation, but don't be too confident about the meaning of a few studies." Amen brother! If one follows the research trail on a particular topic as far back as it goes it can be quite fascinating all the twists and turns have occurred getting from the start to the state of the art. all along the way theories have arisen, been tested and demonstrated to be valid or invalid. Sometimes, a previously invalid theory comes to be understood as valid as the analytical methods improve, yes, it can be a little maddening to the end use folks in the field who may think the researchers are nuts, fools or just plain incompetent at times. In the purest sense, a few studies, even excellent ones, are only a well founded jumping off point for continuing research; in addition, they
can also be the starting point for large scale field trials. Obviously, when enough research is done that comes to enough conclusions pointing in the same direction it is reasonable to conclude that yes, we can go with this. Often it works out over the ensuing years that the research was indeed correct, sometimes it wasn't, science ain't perfect!

Michael,
I think we're all smart enough to know that not all scientific questions have been answered, even without you telling us. I also hope that most of us realize that many have been fairly well studied to the point that at least some answers are fairly clear. The question of whether fruit trees are generally better off if their planting hole is refilled with amended soil does have some complexities, but it's not exactly like we're trying to chart out the Big Bang here. As I have mentioned many times, there are many variables involved, and not all cases will call for the same solution. That doesn't mean that reasonable people should doubt that the world isn't flat or that backfill amendment, used when planting woody plants, often causes more problems than it solves in most normal circumstances.

Brandon, what about something like blueberries when you're irrigating? For woodys that have rootsystems that aren't much leaving the backfill I still can't say that all amending is at best pointless. I haven't looked at nearly all the research, however.

Also, I see nothing in the original posters question limiting amending to backfill. That seems always to be the particular mouse you jump on. The questioner specifically asks how far out should amending be to get any benefit.

Michael, obviously Brandon grasps the points you're making here. I just want to say I don't think you were suggesting otherwise.

It's when I hear someone calling the experts a bunch of idiots I suspect they are frustrated that science can't do a more complete job of making the world less confusing.

Another point I'd tack on to what you've written is that researchers have an inherent interest in exaggerating the significance of their research. When they overstate the implications it makes the work more important and it's human nature to do this. Teachers (or media reports) of research may be inclined to do the same.

However, if the practitioner takes the researcher at his/her word there can be a nasty price to pay. For example, Carl Whitcomb might suggest that he has proven that cutting back branches is not helpful when transplanting trees because he has the results from hundreds of trees and many species that indicate this.

However, if his experiments include only juvenile trees and not a single experiment is done with sexually mature subjects, a landscaper transplanting bearing age fruit trees might be put at a disadvantage by believing the research is as conclusive as Whitcomb portrays it.

As I've stated on this site before, I believe that spur wood has a suppressive affect on root growth while vegetative wood supports it.

Anecdotally it seems like a clear read to me- I transplant 100's of mature and immature fruit trees every year, but I don't have any research to back me up.

In the case of amending soil, if someone insists that all amending of soil is pointless when research is only about amending the backfill of a planting hole, you not only may be giving wrong advice but also leading people to even reject the legitimate conclusions of the research.

"I think we're all smart enough to know that not all scientific questions have been answered, even without you telling us."

I think that would read better without the phrase "even without you telling us". Did you find Michael's tone offensive?

Hman- forgot to mention that I use horse and llama manure as a amendments.

Fruitback, loosening the soil, adding stable organic matter (composted manure) and raising the soil level of planting areas all of a scale that provides room for the roots to grow to is pretty much how I'd deal with the soil you describe, and I don't think it goes against the usual expert recommendations at all.

I just wouldn't have gone down as deep, although I did it almost 40 years ago in CA. The first fruit trees I ever installed were in pure sandstone and I constructed enriched planting holes the size of piano boxes. I had discovered that it worked very well in a smaller scale for growing cannabis.

My bet would be that you'd get the same results with less settling if you limited your excavation to 2' in depth.

When I first planted my fruit trees, I dug deep holes and amended heavily. One of the objectives was to actually limit the tree size through the limit on the root area, I was hoping.

A few years later, I found the roots of those trees far away anyway when I was digging other holes and I have clay soil. So there went my idea of limiting the tree sizes.

Regarding the water table in the hole, depending on the depth of the hole, the rainfall received, whether the water drain away or to, it could be either an advantage of disadvantage.

From my personal experience only, the long term effect of amanding seems to be negligible compared to many other factors.

"...what about something like blueberries when you're irrigating?"

Hman, I'd say blueberries are prime candidates to be part of the exception of the "generally don't use amendments" suggestion/research. No need to go far into the particulars here, because there are whole threads dedicated to the subject, but I definitely amend my blueberry plantings. I do however use much of the research relating to the topics of this thread to guide how much and with what I amend the soil for my blueberries.

"Also, I see nothing in the original posters question limiting amending to backfill..."

I thought we already covered that.

"In the case of amending soil, if someone insists that all amending of soil is pointless when research is only about amending the backfill of a planting hole..."

First, research regarding amended soil has in no way been generally limited to backfill. Some studies may have been focused only on backfill, but extensive work has been done on topics like drainage, nutrient levels, etc in amended soil. Both of the links I used above are focused on backfill, but much of our conversation (as I mentioned previously) pertains to amendment in general.

Secondly, anyone who insists that all amending of soil is pointless (whether pertaining to only backfill or to soil amendment in general) is either trying to grossly oversimplifying things or is not very familiar with the topic. No one, that I saw, suggested that all amendment is pointless. I do however strongly suggest that if in doubt, don't amend. There are times when I amend soil or use amendment for backfill, but I do not do that as a general practice when planting woody plant.

"Did you find Michael's tone offensive?"

Yep, and maybe I over reacted and should have waited an hour after reading his comment before responding. I could probably have done a better job. Maybe he didn't mean to come across as I perceived him to.

"Regarding the water table in the hole, depending on the depth of the hole, the rainfall received, whether the water drain away or to, it could be either an advantage of disadvantage."

Very good point tc88. You are exactly correct, and understanding the principles behind the factors involved with soil amendment can help one to use those factors to their benefit in some cases.

Brandon: it isn't a question of intelligence strictly speaking but rather a matter of whether or not a people have an understanding of the methods and limitations of research. I strongly suspect from reading in this forum and others that the vast majority do not. That lack of understanding says nothing about their intelligence. On the other hand, it can cause them to be easily confused or misled when facing research or as H-man pointed out, it's claims. My intention was to educate the folks with no research in their backgrounds a little about it its strong and weak points s well as how it works.

BTW, I've enjoyed reading all of yours' and H-mans' compelling arguments.

"Another point I'd tack on to what you've written is that researchers have an inherent interest in exaggerating the significance of their research. When they overstate the implications it makes the work more important and it's human nature to do this. Teachers (or media reports) of research may be inclined to do the same."

H-man: I guess I'd make a tiny adjustment by adding, "some" in front of, "researchers". I had the good fortune of working both for and with a number of excellent horticulture research scientists and never even caught a whiff of self aggrandizement in them or their work. On the other hand, I ran into a few who thought they were pretty damned important and that their work was too. Not hard to spot them.
Keep fightin the good fight!

OK, Michael, I understand now. I should have been a little more calm no matter how I took your comments. I guess I was just sleepy and jumped the gun. Sorry.

Blueberries etc. on less suitable soils are responding to the effects acidic organic amendments have on nutrient availability, and not to the change in soil texture - they are not anymore able to benefit from being placed in small areas of one texture surrounding by larger areas of another - or in highly organic amended environments that are going to decompose and settle markedly over time - than any other shrubs (or long-lived plants left in place for many years).

The same result can be gotten by applying chemicals that correct the unfavorable soil mineral situation, and skipping the digging in of bulk organic material.

On compacted soils it is very likely the digging part of digging in amendments that produces any assistance to plant growth and not the amendments.

Better growth from trees and shrubs not planted in amended holes, in the same study plots as those that were given the traditional treatment was being noticed over 40 years ago.

Annual flowers and vegetables tend to be descended from wild species that pop up after major disturbances like forest fires, where the soil may have high amounts of nutrients present due to burning of wood or high amounts of organic matter where there have been other reasons for an opening being created, such as strong winds.

These and other plants with dinky roots can comparatively easily have a special soil environment prepared and maintained for them. Plants that are expected to remain in place for long periods, without them being lifted, set aside, and then replaced after the soil has been re-worked do not lend themselves to being grown in amended beds or strips.

If you want to grow something that somehow really won't be able to take the dirt you already have, the most direct and lasting solution is to get better soil and dump that on top of the existing material, without mixing the two together, and planting in that.

This berm, mound or raised bed of different soil will have to be big enough to accommodate all of the future root growth of the planting.

Only when planting in Pots. When I plant in Pots I mix top soil, Cow manure, saw dust and perlite. (I don't know what the perlite which is a volcanic glass do but I mix some) It will help too to ass some compost. If you are planting in the garden soil just plant it. I have very good garden soil Sandy black so draining is excellent.

bboy, here's my response to your points.

"Blueberries etc. on less suitable soils are responding to the effects acidic organic amendments have on nutrient availability, and not to the change in soil texture - they are not anymore able to benefit from being placed in small areas..."

I don't believe this to be true and even conventional blueberry production guidelines usually specifically recommend growing blueberries in highly organic soil, increasing OM if necessary. Such guidelines would simply proscribe sulfur and other mineral fertilizaton if that was adequate. Adding OM is the most expensive way to go and wouldn't be recommended if alternatives were equal.

I have never seen blueberries growing in the wild in anything other than soil with very high OM content and excellent drainage. Even the ones in marshland grow on organic hillocks.

Even adding mulch does much more than increasing nutrient availability and the most common reason I've seen for mulch being advantagious over incorporation of more stable OM is bang for the buck.

"If you want to grow something that somehow really won't be able to take the dirt you already have, the most direct and lasting solution is to get better soil and dump that on top of the existing material, without mixing the two together, and planting in that."

To say that incorporation of material to an existing soil can have no benefit to woody perenials is to say that all soils are equal beyond what can be adjusted with minerals.

To suggest that carting in an entirely different soil is the better solution than trying to amend existing soil is, in my opinion, applying much to wide a brush to what needs to be determined in a case by case basis. Usually it's more practical IMO to amend existing soil.

I once installed an orchard in what was supposed to be "topsoil" according to the landowner.

It turned out by top soil he meant it was truckloads of "soil" trucked in for free from the top of a nearby mountain or hill being flattened for development. It's primary color was blue-gray and was just about as pure a clay as you'll find- couldn't even support grass.

I used a significant amount of this stuff in the mix and gradually increased the volume of clay in the 15" depth of soil I amended (7' wide raised circles). Against the usual recommendations I even used about 4 cubic feet of sand per tree along with a half yard of compost, most of the sand on the first 3 or 4 inches of depth.

5 years later the instant orchard thrives although it took an extra year to adapt to conditions. The bearing age fruit trees I provided had the majority of their roots too low to immediately thrive in the conditions I created but by the second year of establishment the trees were thriving and the customer got his first crop.

I corrected only as much soil as was needed to serve a semi-dwarf fruit tree and the property owner got his 25 tree orchard for much less than if I'd trucked in all new soil. All the required maintenance is mulching every year so I think it's fair to call the amending a long term fix.

Most studies I've seen that indicate only short term benefits by incorporating amendments involve using raw materials like peat moss that break down to nothing in a couple years as opposed to stable compost. Humus can work magic IMO when used generously near the surface in a way that imitates the soil of the forest. Humus lasts a very long time and is sustained by annual mulching.

I should of said that I used less amendment the further I went down.

Also, Michael, when I said researchers have an inherent interest in exaggerating the significance of their research I wasn't suggesting conscious corruption, only the common human trait (well researched by evolutionary psychologists) to exaggerate personal contributions. It's hardwired into our DNA as negotiators-

Brandon: no problem, I have days like that too.

H-man: I see what you are saying. But, my position is never wrong and I can generate questionable data to prove it :)

Michael, I'm not sure what you're saying. It could be taken as I'm defending my position with questionable data. Very cryptic.

Just kidding, my wife doesn't understand my sense of humor at times and we've been married a long time. The never being wrong part was generated in my mind by a researcher I used to know who was like that at times, thought he was never wrong. Generating questionable data, I.E. cranking out garbage for the sake of appearing to be very active in the field vs doing sound research. Of course saying I'm never wrong is just plain absurdity, the cherry on top. I had to have a strong sense of humor to survive my friends and family growing up.

I've long since given up trying my natural sense of humor on the internet. Without the tonal modulations and the "twinkle" of the eye it's pretty hard to convey irony. Written humor is another art form that I really am not very good at so I can relate. I'll let you know when you tickle my funny bone if you do the same for me. I can only get better.