Georgics, book 2, lines 226–258

Suppose you want to understand
the differences in types of soil:
is this one looser, this one denser than the kind you’re used to?
Here’s the way to do it.
Dense soil’s good for corn; and loose is best for vines.
First pick a spot where you can tell your men
to dig a deep pit in the ground,
then put the earth back in again
and tread it down to make it even at the top.
If the spoil comes short,
the soil is loose, and suitable for pasture
and the cultivation of our valued friend, the vine.
But if it won’t fit back into its place
and there is earth left over when the pit is filled,
the soil is dense; expect to find
tough clods and stubborn ridges there;
to break that ground you’ll need strong oxen.
Salty land — the kind that sometimes we call bitter —
is no good for crops, and ploughing doesn’t sweeten it;
its vines are mediocre and its apples not worth mentioning.
To test it, get your tightly woven wicker baskets
and your wine-press strainers from the smoky roof space.
Fill them to the brim with this bad soil and fresh spring water.
Stamp the mixture down.
You’ll see the water trickle through the wicker in big drops.
Its taste will give the game away;
the tasters’ mouths will pucker at the bitterness.
The only way to know rich soil is to knead it in the hand;
it never crumbles
and it sticks like pitch between your fingers as you work it.
Moist soil can be too rich; taller grasses flourish there
but spare me over-fertile ground,
too strong a stimulant for delicate young corn!
Both heavy soil and light reveal their nature placidly, by weight.
The naked eye can quickly spot black soil
or earth of any other colour.
But the worst of all, and hardest to detect,
is cold soil; only pitch pines, noxious yew trees and black ivy
sometimes indicate the patches where it lies. Avoid!