Study: soil 1.1

1 How do they classify soil types?

Chalk, clay, loam, peat, sand, silt says I know we’re sandy and silty here just from watching my footprints on walks, but I was expecting a more quantitative analysis.

Something more like this tremendous overkill. Oh, I see what’s happened, I’ve found the way to describe soils’ physical behaviours – the things you’d want to know if you were building on it or drilling through it. It’s interesting but not yet.

I’m more at this level right now. (Hurrah for them for getting a good domain name!) “Sand grains, mostly from weathered rock, are coarse and gritty; clays are fine-grained and feel sticky. Intermediate- sized silt grains feel silky. Clay soils are mouldable but sandy soils fall apart.  You also find ‘Organic matter’ in soils[…]” Ok, so the structure is genuinely about grain size. And that affects how water and air move through the soil layers.

2 How did they classify soil before that? says I’m thinking of soil in the manner of a nineteenth century man. It can be thought of as broken down rock which has been acted upon by life forms, but really it’s more dynamic than that.

I think that description sounds plenty dynamic. A rock face gets newly exposed, broken into bits that offer cavities and shelter and water pools, and tiny tough life lands on it at random and thrives. And then the tiny tough life changes the shape of the rock and excretes stuff that slightly less tough life can use to thrive on, and so forth.

I hope I’m only simplifying and not completely wrong, because that story is marvellous.

3 What is our soil here?

I was digging this morning and it’s absolutely definitely 100% silty.

No, it’s “freely draining slightly acid loamy soils”. Loamy is cheating: it means it’s got sandy AND silty AND clayey particle sizes as well as live matter. And as far as ‘freely draining’ is concerned I have my doubts. It can rain hard enough to bounce tiles off the roof and the next day you cut down four centimetres and the earth is bone dry again. “Suitable for range of spring and autumn sown crops; under grass the soils have a long grazing season. Free drainage reduces the risk of soil damage from grazing animals or farm machinery. Shortage of soil moisture most likely limiting factor on yields, particularly where stony or shallow.” Ok, that sounds reasonable.

4 What would you add to change it to the other types?

You could literally go to the beach and Shawshank yourself a sack of sand? No, I composed this question when I thought soils might be classified by their nutrients, I was thinking of fertilisers. You could add worms to keep live matter moving through the rock particles. We add compost and fork it in between plantings, and I usually sieve rocks out and fling them in the hedge at the same time. (How DO rocks turn up in perfectly reasonable soil?)

5 How do soil multimeters work?

The ones I’ve seen have two prongs and measure the resistance of the earth between them. That’s fairly straightforward: wet will conduct better than dry, and fluids with a ton of free protons will conduct better than not, I mean, that’s what pH _is_.

Some of the devices also say they measure light levels, which… I’m not absolutely sure why I want a device for that? Unless it also gave you a history / record, like those greenhouse thermometers that will tell you the hottest and coldest it’s been in the past 24h. It might be good to know that your possible courgette location will only get six hours direct sun a day.

6 What is John Innes No 3?

Explained in glowing fullness at – it’s a certain ratio of a specific nutrient mix added into a specific soil mix. And it’s called number 3 because it’s stronger than number 2 which is stronger than number 1, which is why you use it for established plants or plants you want to bully briefly. You get 9 litres of {half medium sterilized loam, quarter peat, quarter sand} and add 84g (3oz) John Innes Base {2 parts by weight hoof and horn meal (or 2/3 of a part by weight Nitroform*), 2 parts by weight superphosphate, 1 part by weight sulphate of potash} and 15g ground chalk. 

Now I remember this from before: NPK fertilisers. N for leaves, P for fruit, K for stems? And the chalk is to alkalise. 

7 Could I compost hutch sweepings at home?

Sure. It shouldn’t even smell. I might try to source a plastic pipe, like a drainpipe or wider, and just drop the hutch sweepings in at the top. It’ll be high NP. 

8 What’s the name of that Japanese compost accelerator I read about?

Pretty sure it was called Bokashi and none of the sites will tell me what it actually is. They all cover it in ‘don’t you worry your pretty little head about it’ terms like ‘beneficial microorganisms’. It ferments the rubbish, basically, meaning you can then compost it faster. Seems a bit irrelevant, to be honest. Perhaps I’ll test it some time when I have space to run a direct comparison. 

9 What’s in the compost accelerators I see in normal shops?

I’ll have a look tomorrow. I do hope it’s some seventeen-syllable destruction-ase and not more unspecified beneficial microbes. 

What connects those answers?

The balance of structural particles and living or once-living matter. tiny creatures that can turn _literally air and radiation_ into sugars and then starches and proteins. If you’re not confused you’re not paying attention?

Questions for next time:

  1. What did I once read about sunflowers pulling poisons out of earth?
  2. What does too much ‘organic matter’ do to a plant?
  3. What’s wrong with that compressed coir stuff?
  4. Why is it N for leaves?
  5. Why is it P for roots and flowers?
  6. Why is it K for stems?
  7. Find a summary of crop rotation.
  8. Find a summary of organic certification.
  9. What connects those answers?