Soil - where it all starts and ends: Basics

[Note: Me and a bottle of my home brewed, 2 year old, blackberry wine have been sitting around all day thinking about how to tackle the subject of "Soil". Not only what to say, in which order, but also how to present it. I hope to be able to create a sub-forum for Soil and then put in it all the Soil related threads. It is a large and varied subject. We're going to need to cover, among other things, What is Soil, cover crops/green manure, mulching and types of mulchs, adding (or not) nutrients (like kelp, blood, and bone meals), Till vs No-Till, preventing soil erosion by improving soil structure, improving microbiotic activity, water infiltration rates, lots of stuff. And of course the big one - compost (making and using). For now we'll start with the basic things.]

What's the difference between soil and dirt?

Some folks say: Have you ever heard the old adage, "weeds are simply misplaced plants"? Likewise, dirt is misplaced soil, that is, it is somewhere where it doesn't belong, like in your carpeting or on your kitchen floor. Dirt is under your finger nails, soil is under your feet.

Screw that. To me, Soil is much too important to try to be cutesy about it. I take Soil very, very seriously.

Soil:

According to the USDA, soil is defined as: "Soil is the natural medium for the growth of land plants---it is a natural body comprised of solids (40% mineral and 5% organic matter), liquid (20-30%), and gases (20-30%) that occurs on the land surface, occupies space, and is characterized by one or both of the following: horizons or layers that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter, or the ability to support rooted plants in a natural environment."

According to a publication for Master Gardeners, soil is defined as: "Soil is the result of parent materials (rock) having been acted upon by climate and vegetation over a period of time. It is weathered rock fragments, with decaying remains of plants and animals (called organic matter). Soil also contains varying proportions of air, water and microorganisms. It furnishes mechanical support and "food" for growing plants." As for composition, an "ideal" soil contains: Mineral-45-48% of the total volume, Organic-2-5% of the total volume, Pore space-50% of the total volume (composed of 25% air, 25% water).

Dirt:

According to me: Soil is alive, dirt is dead. It contains no organic matter, micro-organisms or signs of life, and is usually compacted or too easily washed away. It won't allow water to penatrate or water will go right through without being held. Dirt is what you end up with if you start with good natural soil, add synthetic chemical fertilizers, pesticides, and herbicides. In addition, you use the soil but don't return organic matter and other natural nutrients.

Improving your Soil is something you, as an Organic Gardener, will always be doing. Either your Soil is poor and needs building up, or you've been using it and need to replenish it.

I always suggest that if you are just starting out, get a soil test. A good, professional one. And then get another test every 3 or 4 years - that's very important. In the U.S.A., as far as I know, all the agricultural universities have county agents who can help with this. The tests are fairly priced and very well worth it. In all cases I am familiar with, they'll not just tell you what you've got but what's needed. Tip: make it plain that you want Organic Gardening results. Another tip: Every chance I get I use agricultural universities. Their info is expert, local, up-to-date, and usually free - hard combo to beat.

If you are a non-U.S.A. gardener and can't find similar help, let me know, I'll try to help find it. If you are a non-U.S.A. gardener and know where to find similar help, please share that info.

Here are 10 tests (from Organic Gardening Magazine http://www.organicgardening.com/feature/0,7518,s1-3-78-314,00.html) you can and should do yourself. It is really important to do these, not just for the results, but as a way to get to know your Soil & to keep "in touch" with it. Check various locations in the garden for the broadest picture possible. The more detail you have, the more accurate and reliable the results.

Test 1. Soil structure & tilth
When the soil is neither too wet nor too dry, dig a hole 6 to 10 inches deep. Separate an intact section about the size of a soup can and break it apart with your fingers. Determine whether the soil is cloddy, powdery, or granular. Ideally, your soil should be made up of different sized crumbs that will hold their shape under slight pressure. Crumbs, or aggregates, as soil scientists call them, that break apart only with difficulty mean your soil is too hard.

Why it's important
"Soil rich in organic matter tends to form relatively round aggregates, which leads to porosity," says Tom Thompson, Ph.D., professor of soil science, also at the University of Arizona. Open, porous soils allow the free movement of water and oxygen, he explains, so plants can develop strong, healthy roots.

Test 2. Compaction
Plunge a wire flag (metal coat hanger) vertically into the soil at different locations. Mark the depth at which the wire bends. The sooner it bends, the more compacted the soil. A foot or more of easily penetrable soil is ideal.

Why it's important
Compacted soil inhibits root growth and water availability, and keeps earthworms and other vital soil fauna from circulating freely.

Test 3. Workability
You may have already learned about your soil's workability the last time you got the garden ready for planting. If tilling or digging the soil produces cloddy or platelike clumps, the workability is low. Farmers measure workability by monitoring how much tractor fuel they use; you can simply judge the effort necessary to prepare beds for planting.

Why it's important
Soil that's easy to work allows water to reach roots efficiently and is less prone to compaction. Fail this step, and your garden will likely show disappointing results for many of the other tests. "If the soil isn't easily worked, other problems have already been going on for a while," says Raymond Allmaras, soil specialist with the USDA's Agricultural Research Service in St. Paul, Minnesota.

Test 4. Soil organisms
Measure the animal life in your soil by digging down at least 6 inches and peering intently into the hole for four minutes. Tick off the number and species of each organism observed, such as centipedes, ground beetles, and spiders. Because most soil organisms spurn daylight, gently probe the soil to unearth the more shy residents. If you count less than 10, your soil does not have enough active players in the food chain.

Why it's important
A thriving population of diverse fungi, bacteria, insects, and invertebrates is one of the most visible signs of soil quality. The more that creeps and crawls under your garden, the less opportunity there is for pests and disease. Each level of soil life does its part to break down plant residue and make more nutrients available for plant growth.

Test 5. Earthworms
When the soil is not too dry or wet, examine the soil surface for earthworm casts and/or burrows. Then dig out 6 inches of soil and count the number of earthworms squirming on the shovel. Three worms are good, five are better. The absence of worms means the soil does not have enough of the organic matter they feed on. An exception: If you live in the Southwest, don't waste your time looking, even if the soil displays other conditions of soil quality. "Earthworm activity is less likely in the desert," says the University of Arizona's Dr. Walworth. "Worms don't like hot soil."

Why it's important
Not only do earthworms aerate the soil, but their casts infuse the soil with enzymes, bacteria, organic matter, and plant nutrients. They also increase water infiltration and secrete compounds that bind soil particles together for better tilth.

Test 6. Plant residue
If you've grown a cover crop, dig down 6 inches one month after turning it into the soil and then look for plant matter. The range of organic material is important to notice here. The presence of recognizable plant parts as well as plant fibers and darkly colored humus indicates an ideal rate of decomposition.

Why it's important
"The single most important component of healthy soil is organic matter," Dr. Thompson says. But plants and other organic materials decompose only when soil organisms are there to do the work. Any sign of this process is a good sign, but the speed of decomposition is important, too. Fast decomposition is another indicator of soil quality. In poorly aerated soil, plants break down slowly, a condition that gives off a faintly sour scent.

Test 7. Plant vigor
Start this test during the active growing season and look for healthy plant color and size that's relatively uniform. Overall health and development must be judged for what's considered normal for your region. One caveat: If you planted late or during a drought, or suffered a pest infestation, results of this test may be unreliable.

Why it's important
Plant vigor indicates soil with good structure and tilth, a well-regulated water supply, and a diverse population of organisms. It's the best sign of effective soil management you'll have above ground.

Test 8. Root development
Use a shovel or hand trowel to dig gently around a selected plant, preferably a weed you won't miss. Once you've reached root depth, pull an annual plant up and check the extent of root development, searching for fine strands with a white healthy appearance. Brown, mushy roots indicate serious drainage problems—and a poor outlook for this year's harvest. Stunted roots might also indicate disease or the presence of root-gnawing pests. "When you look at the roots, you can really see what's going on," Allmaras says.

Why it's important
Roots have the most immediate connection with and reliance on soil quality. Without air, water, biological activity, and crumbly soil to grow in, roots can't do their job.

Test 9. Water infiltration
Take an empty coffee can with the bottom removed and push it into the soil until just 3 inches remain above the surface. Fill the can with water, marking the water height, and then time how long it takes for the water to be absorbed into the soil. Repeat this several times until the rate of absorption slows and your times become consistent. Anything slower than 1/2 to 1 inch per hour is an indication of compacted soil.

Why it's important
Good infiltration gets water to plants where they need it—at their roots—prevents runoff and erosion, and lets air move more efficiently into soil pores.

Test 10. Water availability
Wait for a soaking rain; then record how long until plants start to show signs of thirst. Results will vary widely by region. The basic lesson is that if plants require more frequent watering than typical for your region, your soil is probably the culprit.

Why it's important
Porous soil can better resist evaporation and adequately supply plants between waterings. "It could make all the difference in the world if water were to go another inch deeper," Allmaras says.

Oh yeah, here's an 11th test: Take a really large clear glass or plastic jar or bottle. Using a small garden trowel, dig up some Soil and fill the jar 1/3 to 1/2 full. Then fill the jar with water. Shake well. Set the jar down and let the muddy water settle. You'll probably have three layers show up in the jar. They will be, from top to bottom, silt, sand, then clay. This will give you a little more info about thecomposition of your Soil.

Peace,
poor_old_dad

 

soil is something i get very paranoid about. i get stuck on it sometimes and have trouble moving forward. i'm always afraid i'll invest alot of time and energy and money into developing a gardening plot and not realize that there is some toxic poison in it that i'm unaware of...especially in a place where people have been living and working for a long time. do you know of any good, affordable soil testing service that can test for a broad range of things that can turn up in soil, like pesticides, petrochemicals, lead, etc.? i've looked around but all i ever found was a lead test kit for $40.

 

My Dear Ms. Freaks,

You bring up a good point. It is important to be careful when following other folks. Extra much so if you're going to garden where other have lived & worked. Extra, extra, extra much if you want to garden where others (but you don't know who) have gardened. Home gardeners, according to some studies, are 20 times more likely to over use chemicals than farmers. Hard to over use compost.

It has been a while since I into soil testing to detect the type things you mentioned, so let me (pardon the pun), do a little digging and get back to you.

Peace,
poor_old_dad

 

Ok, well, here's a place to start on the "Where to get a soil test" question.

http://www.organicgardening.com/soiltest/1,7775,s1-2-7-0,00.html

This covers the U.S. and Canada. I'm still working on where to get the more complicated tests for things, "like pesticides, petrochemicals, lead, etc."

Peace,
poor_old_dad

 

hey there, I've got a question for you.

I was at agway last month, and they were selling - very cheap- something called winter barley. My research says it is for "building the soil", but could you tell me what to do with it? It's growing like crazy in a plot I plan on screening to get the rocks out, and I've also planted it around my garlic bulbs at the community garden. I have a bit more left, should I scatter it on my raised bed? What is this stuff?

The raised bed is a painful issue. Landlady told me it was "compost" and later told me it was "compost" on top of "clean fill". The frame for the raised bed is pressure treated lumber, which she claimed will last longer. Well no shit, if you leave out a plate of poison, no one will eat it. I ripped out all root veggies anywhere near the edges.

Then I found out her idea of compost was to just throw her kitchen scraps in a general area, as spread out as possible. The testing I did revealed nitrogen at the lowest levels the test reads at the surface, and nothing at all about 6 inches down. This was after I took her word for it and planted. I've been keeping the plants on life support with human urine diluted 10:1, but I'm concerned about salt buildup. I got peletized gypsum on the cheap (ripped bag), should I mix some in this spring?

While I'm at it, can you ID the pollinator in my signature pic? I snapped that shot of the little guy on a cilantro flower. It's like a very tiny bee.

 

i just checked,poor old dad hasnt been online since june 20th..

i hope hes well.. he has a wealth of knowledge to share..

does anyone know how to contact him other than online?

if so could you PM me the info? we would like to know hes OK..

 

hopefully he's just enjoying a great harvest and has no time for the net. He seems like a very wise dude.

Think positive!

 

I think what y'all were thinking of is a fast-growing, nitrogen fixing crop that you grow after the growing season, let it die, and mulch it in to compost.

Most potting soil sold is pretty dead and requires a nice packet of aerating compounds to grow, as well.