Simple Soil Tests in your woodland ~ by WoodlandsTV

Transcript

Julian Evans: The soil, the soil profile, is crucial to the well-being of woodlands, of trees, of forests. After all, they provide the anchorage for the tree, they provide the nutrients, and, of course, they provide the moisture. And there are a few simple tricks that we can do to learn a little bit about the soil, even for a small woodland owner who has not had any background in doing soil science. And if we look at this crack into this woodland here, the first thing we can see is how rutted it is. Such ruts, such banks and cuttings that vehicles have made are a real bonus, because it allows us to look, crudely albeit, at the soil profile. Normally, of course, a professional soil scientist would dig a nice soil pit and check through the soil as he dug, but here we can walk over and look at this bank.

Firstly, we can see how this hornbeam tree is beautifully anchored into this bank, and that was one of the three roles that soil plays. But what is important when it comes to understanding the soil is actually to look at what we call the "texture" of the soil.

And all soils, apart from the organic matter which is at the surface, which is made by the leaves and the twigs and the bits of bark and the cones that fall from trees and plants that creates the humus that we'll all be familiar with, soil itself is composed of clay, of sand, and silt. And the proportion of those is really quite important.

I expect all of us have clumped across a farmer's field and found that our boots and wellies have become all claggy with soil. Well, that's a really clayey one if that's what happens. If on the other hand, we walk across the field and there's relatively little soil attaching to our boots, well, it's probably much sandier. But there is a way that we can do a test on any kind of soil, and that is what we are now about to do.

So, the question we want to answer is, "What is the texture that we have in our woodland soil?" And here is a piece that's about, I suppose, the size of, oh, an old penny, a 50 pence piece, but of course, it's round. And what we want to do is to try to work it with our fingers and thumb, on the hand. You need a bit of water, and the traditional way of doing that is to spit on it and work it and work until it is a gooey, sticky mass. And then we can begin to do our tests about what this soil is like in terms of its texture.

And the very first one is to see if we can make it into a ball, and there you can see we can. And straightaway that tells us this is not a sand. Well, we knew that anyway, because we all recognize sand. But if the soil is almost a pure sand, and we do grow some of our woodlands on almost pure sand, you could not make round ball out of it. So, we know it's not a sand.

The next thing is, we roll the ball between our two hands, or perhaps with the fingers and try to make the whole thing into a sausage or a column. And here we are, we're getting into a kind of a sausage shape, but it's not going terribly well. And that's telling me something already - that bits are beginning to break off, though I can just about hold up the sausage, but only just, which indicates it's probably getting towards a loam, which is a lovely garden-type soil, a loam.

But at this stage, to learn whether it's a clay, you want to try and see if you can make your sausage into a complete circle, or at least a "U, " without breaking, because a really sticky clay not only would have left your hand much dirtier than mine, but it would have curled up beautifully, and this one as you can see has broken.

So, I'm fairly confident that this soil is at best a loam. It's got quite a bit of sand, probably some silt, and not as much clay as a really sticky clay. So, we've answered the basic question is that it's a loam. There's one more question we want to ask of our soil. Is it a sandy loam or a silty loam?

Well, soil scientists who are experienced at this will take a little bit of the soil, and they will listen to it, and sometimes, if it's sandy, you can here the bits of sand. Now I can't hear anything at all. And you can feel that it's slightly rough between your finger and thumb, but no, I can't hear anything at all.

Indeed, this is much more soapy as a soil. It's almost like a kind of gunginess, a greasiness, without the stickiness, and probably that indicates a high level of silt. So, probably, this is a silty loam, quite a good forest soil, not terribly well-drained, but reasonably well-drained, and certainly ones that can grow a good forest crop, a good woodland crop.

So, there we have it, the basics of assessing soil texture. You take some soil and then do the sampling. You knead it in your hand, and then you see whether it forms a ball or whether it then can bend round when you've made the sausage, and depending on how far you get, depending on how near a clay it is. Thank you.