If you think of it this way, in a forest, the cycle is continuous, year in, year out. Nutrients are recycled via plant matter decomposition, rather than fertilizer application. Read "Gaia's Garden" by Toby Hemenway. It might give you a different perspective on the whole process...

Because the Soil Food Web, the wee buggers that feed your plants, need a constant source of organic matter you will always need to add that organic matter to your soil, just to maintain the 6 to 8 percent level they will need to function well. Beyond that when your soils pH stabilizes where it needs to be (for most plants that would be between 6.2 and 6.8, although some need something different) and the nutrients are in balance.

ok sb... I agree adding om is where it`s at. However if that`s all there were to it, I could take a picnic basket into the woods and come out with corn, cabbage, tomatoes and such... It works for trees, where I`m heading with this is that in nature, plants tend to grow in the conditions that suit the particular plant. Bog plants grow in bogs, desert plants in deserts and so on...

Ok Kimmsr, so in what balance? I`m concerned with flavor (which I BELIEVE go hand in hand with nutrient density), pest resistance, and lastly productivity.

Maybe I`m being anal, but, I have the ability to change my garden to better suit growing vegetables. Why not take advantage of our abilities? I`m interested in where to draw the line with for instance potassium. Too much and it will effect other nutrients, not enough and you won`t get optimum growth. Where is the line to stop adding concentrated ammendments? Compost will add these things(as well as help make available) nutrients and micros, but the micros need to be in the raw materials of the compost to be there at all. I like compost and make and use it. It is great for maintaining om and nutrient levels and certainly helps with tilth. Sorry for rambling... I`m just interested in the science behind it...

Maybe I should be also asking how low is too low before action should be taken?

A forest does not build OM even remotely at the rate that most organic gardeners add it to garden plots. By orders of magnitude. So any comparison to a natural system is invalid.

My home garden soil, for example, is close 50% OM by volume. This condition has not solved all vulnerabilities, particularly insect predation issues. Always this discussion comes back to the relative value of the OM - it isn't all the same. It cannot be shown that only additions of OM will solve all deficiency problems in all situations. In many if not most cases it will not solve all problems. Therefore it makes no sense to drive percentage OM levels up without limit.

sb 158, forest builds about 1 inch in 100 year or so.
But you are right that is continues to build day & night 365 days a year, just very very slloowwllyy.
jon dear, you have 3 plant groups for compost needs:
Heavy feeders:beets,corn,kale,squash,tomatoes,cukes.
Light feeders:carrots,Garlic,peppers,turnips,onions.
Soil Builders: beans,peas,clover,peanuts,alfalfa,buckwheat.
They should be rotated in the order they are listed.
It is hard to keep up with what needs more OM & when, so I spread heavy OM(4-6") after harvesting last season vegetable.
If it is a perennial crop, I just sprinkle the compost on top.This is what I use.IMG_2391.jpg

Here is a link that might be useful: compost used every season

Many organic gardening researchers have noted that when Soil Organic Matter drops below 4 percent more plant problems appear, more insect pests and pant diseases seem to be attracted to the plants trying to grow in soilks with those low levels of SOM.
What does your state Agricultural schools research people, the Cooperative Extrension Service resource, have to say about nutrient balance in your soil?
One thing that really amazes me is the number of people that have paid for the knowledge accumulated at these universities and that refuse to use any of it.

my soil test said om was 11.4%
maybe why iron tests low... I don't know.
U Maine uses modified morgan extract. As to the extract solution, they use ammonium acetate at 4.8 pH. P and K are actual P and k.
* As far as target values-
Phosphorous 20-40 lbs/A
CEC greater that 5
K 3.5 to 5 %
Mg 10 -20 %
Ca 60-80 %
acidity less than 10
OM 5-8 %
sulfur greater than 15 ppm
copper .25-.60 ppm
iron 6-10 ppm
Manganese 4-8 ppm
zinc 1-2 ppm

So I'm thinking that's based on sufficiency thinking (remnants of chemical ferticulture) not for soil building levels. I might be all wet.

The thing is they base a lot on percentages and I don't know what level things *should* be at. If the percentages were in line but all at low levels vs. all percentages being in line at high levels there'd be a big difference in the crop right?
I'm wondering let's say where I want to be with P and ca... is that the staring point?

At the present time it is pc to hold phosphorus levels low. Some fertilizers are purposely omitting phosphorus. In my opinion for best taste and brix you need higher P. Phosphate is 44% phosphorus while potash is 83% potassium.

I read that phosphorus tends to bind to the soil. Perhaps most algae bloom in lakes and reservoirs is due to household dumping down the drain?

Maybe I`m asking my question wrong. Let`s say I going to GIVE you a billion cubic yards of the most beautiful loam you`ve ever seen. Perfect tilth, smells good, not full of rocks, looks like nothing you`ve ever seen before. There is a catch though- you need to tell me what nutrient levels you want in your free soil. And you must plant it all to mixed vegetables. You can`t sell it in bags as fertilizer -just in case someone was thinking there`s more money in "whatever" than in growing vegetables. Where would you want your nutrient levels?

Many of the soil testing labs report the test results as Optimal, Low, High or they will have charts that show what the optimal levles of nutrients are. Those are where you ewant your nutrient levels to be, in the optimal range.
Once "banking" of nutrients was thought to be something that should be done for the future, but now we know that excess soil nutrients do flow out of the soil with the excess water, they do not store in soil, and contribute to the pollution of our world. Imbalances of soil nutriewnts also create other problems because excessive amounts of one cause a plkant to not be able to utilize others, ie. excess amounts of Phosphorus can inhibit a plants ability to properly utilize Zinc, Iron, and/or Cobalt. Excess amounts of Potash can cause a plant to not be able to utilize Nitrogen. An imbalance of Calcium and Magnesium makes use of either by any plant difficult, they do need to be in balance, not equal but in balance.
Soil pH also needs to be close to what the plants need and for most of the ppnats we grow that is between 6.2 and 6.8 where most all soil nutrients are most readily available.

There are large stores of minerals in good soil that are locked up and not subject to much leaching. Then there are smaller amounts of minerals being broken down in form and made plant ready. When these plant ready minerals are not taken up that season, they are more likely to be leached out in higher rainfall areas.

Well guys, I concider you a good source of informaton but sometimes it`s like pulling teeth... Also what I currently have is an upsidedown P & K ratio. I can`t fix it by adding more leaves and compost. That would likely drive my potassium higher wouldn`t it? I probably won`t get it in the "right" ratio this year but I want to at least be heading in the right direction. Otherwise what sense did it make to have a soil test done... I could have just kept adding compost without paying for a test. I HAVE the information and just wanted to make the best use of it.

I`ll try to hold my nutrients I do have with covercrops in the off season. I didn`t grow any this past fall at this garden spot (i have 2) because i muched heavily with shredded leaves. I turned them in a few weeks ago because they were insulating the ground causing it to not warm up. The old troybilt had a time bringing up much dirt. Tilled again today and found that decomosition is starting. The garden is starting to look like a nice potting mix. But that is, as i said, probably contibuting to my upsidedown ratio.

I find it easiest to consider the soil block as a dynamic equilibrium. Change one parameter and it often affect many others, to varying degrees. Too much o.m., maybe your soil temps are slightly depressed or the pH is slightly more acidic or you affect soil aggregates forming -- or some other obscure bio/chemical/physical soil association that changes in accordance to your soil amendment.

Assume the soil is static and never feed or care for it and it will lose fertility season by season. Go by someone else's rote instructions and keep pouring on new amendments w/o regard to what has actually been depleted or become unavailable for root uptake and knock the soil system into a less favorable dynamic for your plants. I don't think anything replaces the various scientific tests - which don't always have to be lab tests - that reveal the various soil properties month by month and year by year.

You?ll never stop improving the soil, but sometimes you can coast for a while and just tweak things a bit. An annual soil test will tell you where you?re headed. Be sure to write ORGANIC on your test request, as most labs will automatically give chemical farming info.

Natural inputs come in organic and mineral forms, or a combination of the two.

Organic Matter is basically unbroken-down compost and the manure. Both contain varying amounts of nitrogen, and both CAN contain various amounts of various minerals, esp phosphorus and potassium, but there's no guarantee as to levels, because the compost ingredients and the animal feed nutrient values vary all over the place. HUMUS is OM that has been completely broken down by soil microbes, and is the long-term source of nutrients. They are not one and the same.

A volatile nutrient like nitrogen can be washed out, blown away, off-gassed due to plowing, or used by the crop. Any of these can reduce the amount of what you think you've got, even from week to week.

Minerals come from the soil, from broken-down rock. Some of them are in the organic matter, but not everything your plants need; some just plain isn?t there and won?t be there unless you make a point of specifically adding it. The more crop residue you return to the soil, the more minerals it will retain.

Your local soil and climate is going to affect what your soil contains and maintains. If you live in a warmish area with not much more than 25" of rain and a fair (but not excessive) amount of clay, your soil will hold more nutrients than a rainy place. If you live in a wet climate, quite a few nutrients will be flushed out of the root zone by the excessive rain. If you live in a hot place like SoCal, TX, AZ or FL, the heat cooks the OM out of the (usually) sandy soil, but you might retain more minerals.

What do your soil test results look like from your unfertilized soil? That's a major clue as to what you're going to have to keep up (or suppress), so find a spot that hasn?t been fertilized or mineralized if you have never gotten a soil test. And your soil pH is going to influence how much of the various nutrients are going to be available to the plants. Just because it?s sitting there in the soil doesn?t mean the nutrients are available.

Here in the PNW, soil tests show how the heavy rainfall leaches out nitrogen, potassium, calcium, magnesium and boron -- IOW, all the main important stuff. We either have to keep adding it, or grow fall cover crops that will bind up some/most of those minerals and hold it until the cover crop is incorporated in spring. Some things, like boron, have to be added continually.

What levels are ideal? It depends on what you're growing, as different food plants need different amounts of nutrients. Corn is the big nutrient hog. "Jolj" gave a basic list above. If your soil is nutritionally balanced, you can plant things closer together. If it isn?t quite up to par, space them further apart than recommended so their roots can search for nutrients.

Here is what I?ve been able to glean from various sources, so far. Please chime in, folks, if you think my figures are off. Also, different labs use different methods, and those methods may produce different results. It?s not advisable to skip around from lab to lab. Find one you like and stay with them.

Nitrogen: 5% good organic matter should have an estimated nitrogen release of 100 lbs of nitrogen per acre (100 ppm). Is that enough for the crop you have in mind? If you have too much nitrogen due to an overload of compost, the nitrogen will drive some calcium out of the soil, and your crop yields will suffer. If you add a LOT of OM and you have disease or insect problems, something else is off, probably due to the excessive nitrogen levels. Too much of anything will almost always cause trouble, including drinking excessive amounts of water. Moderation is the key.

Phosphorus: 30 to 60 ppm. How much is available depends on your soil pH ? the closer to 6.5, the better.

Phosphorus: 120-200 ppm, but it has to be available, not just sitting there inert.

Calcium and Magnesium: The total combination of calcium and magnesium should total 80%. Normal soil should be near 68% calcium + 12% magnesium. But if your soil is sandy, 60 + 20 would be better. A heavier clay soil, 70 + 10.

Keep in mind that although lime contains calcium, you have to know your soil pH and your calcium/magnesium percentages to be able to choose the right calcium-based minerals to use.

Sulfur: 20-25 ppm, up to 50 ppm for high-yielding crops like woody plants and pasture.

Sodium: Some of the areas of the country tend toward excess, above 3%. Other parts of the U.S. go the other way, and a deficiency is often less than 0.5%.

Micronutrients only make a difference when all of the above primary and secondary nutrients are balanced.

Boron: 0.8 ? 1.5 ppm. This is the least stable of the elements, your crops need a steady supply, it can?t be reused. Boron is one of the few elements that can?t be built up, so if it isn?t naturally in your soil, you may have to add it every year, and maybe even through the growing season.

Chlorine is chloride: it normally isn?t deficient, esp if your calcium level is good; but excesses (usually much over 250 ppm) are known, esp in compacted soils, or known saline soils, and it isn?t easy to deal with.

Molybdenum: 0.01-10 ppm.

Copper: 2-10 ppm, but 5-10 is best. Most soils are deficient, but once you get your level up to par, copper is stable enough to stay there for quite a while. Copper and Molybedenum work together, so test and treat for it together properly.

Iron: 200+ ppm. Check for it in chalky, high-calcium soils, where it is most likely to be deficient. Excess iron isn?t a problem. Iron works with manganese and sulfur, so check levels for all three. Lime added within 3 years will affect soil tests.

Manganese: 40-250 ppm, but best results in 80-125 ppm range.

Zinc: 6-12 ppm, 10 is excellent. Once the levels are up to par, it is easy to keep it up on clay and humus. Too much nitrogen will tie up zinc.

Suggestion: for more info, get hold of Neal Kinsey?s book Hands-On Agronomy, available in the library system.

Sue

Lots of good advice and points of view here.

I have noticed two approaches, (as a reslut of how I personally have rationalized the issue); one with the soil test and trying to adjust soil to recommened levels. It works very well even if you only manage aproximately, it's not that easy to be exact with orgaics, but luckily not needed either.

The other is carefully attending very regularly like ever week or other with fertilizers and amenments. That is the approach of those who grow vegetables for show and competition. I used to think these vegetables would taste less, some how a bit like a broiler chicken, but these are really very good vegetables. I have had the chance to test taste from different growers. What matters more is freshness, and direct harvest from the garden.

Another trick is to add seaweed like Ascophyllum nodosum, or the most nutritious (N ad K, and trace element wise) kelp. It is known to be more benefitial to some vegetables than others; good for carrots for some reason.

There is lot to show for adding really good composted organic material compared to less composted. For example in the literature it is mentioned that a lot of less composted manure give soft fruit which isn't that good. However, optimal nutrition needs to be added, and it makes sense to differ between compost and fertilizer. Both are essential for optimal results according to one camp.

Neal Kinsey is well worth reading.

Jon, I think you are spot on: if one is simply going to continually add compost to the garden, then why bother with soil testing? One does not need a soil test to make an accurate approximation of the percentage of well-broken down OM in the soil, so the purpose of the test is exactly to know if there are necessary nutrients not being adequately supplied by the compost.

And as belgianpup importantly points out eventually compost and or manure drives N too high and leads to insect problems - that is what I have been dealing with in the home garden for some years.

I'd like to add that a chalky soil is not likely to have insufficient iron, it's a rich soil in general due to it's high pH, in fact it's the pH of the chalky soil which allows it to collect iron and other minerals so well and so tightly, that the plant expends more energy competing with the soil for their uptake. But that's why we have adaptable plants and trees that can do just that.

Likewise, due to this retention ability, adding unnecessary iron or any other mineral can be quite problematic with this soil type. An acidic soil is much more forgiving to carelessness, because nutrients are constantly being leached out, rather than retained. Toxicity can be introduced easily into chalky soils and it is slow in it's correction.

I'd also like to add that a pH in the six range is not an ideal goal for a chalky soil, the soil may be chemically and biologically unstable in this range. What we don't want to do is via improper irrigation or fertilization, push the pH up and out of range for adapted plants or trees.

The typical shortage if there is one in chalky soils is not enough carbon. Carbon is constantly being used to faciliate all the biology and energy involved in extracting nutrients that are in abundance, but tightly held, and into the adapted plant. One could say that it's the soil type that invented the need for an organic approach.

Like others have said you don't stop building soil. You need to know what type of soil you have & what is recommended in your climate.

I don't have numbers, but have been building soil for years expanding garden space as I go, so some areas are loose enough to dig with your hands & others have 5 gallon bucket of rocks if you're digging a 2' hole. Our soil is rocky clay with poor drainage. Sometimes I find a deposit of gravely glatial till. We have a long rainy season with acidic soils, so need to add lime yearly to vegetable gardens. I think my garden soil that I've worked is pretty good now as long as I maintain it with yearly additions of compost and/or mulch. If I leave off the mulch in an area like under fruit trees I get annual weed germination, so cover with newspapers & mulch again to remove them.

I try to think of it as cake:
-Mix up the batter with a garden fork (soil + compost), then frost (mulch).
-Since we eat cake up (like plants use up the organic matter & it breaks down over time) I mix up another batch (add more compost) & frost again (mulch).
-Each fall I either make more cake or just frost it (mulch). I often use uncomposted manures in fall. I also add lime.
-Each spring in raised beds for greens, root crops, brassicas, & alliums. I add granular organic fertilizer & mix it in. After soil warms I mulch again.

I used to do a lot of double digging or mixing up the compost into the soil, but now I just use the garden fork now & then to work it in if I'm planting seeds. Otherwise I leave it chunky & the mulch smooths out the top. I haven't noticed a big difference between my digging it up years & now that I layer & leave it be. It's just easier now to garden that I don't till everything by hand anymore.

Hope that helps~