How to calculate worm numbers

[Susmith]

How can I calculate how many worms there are in a piece of land?

[pathfinder]

It has been calculated, from the number of worms found in a measured space in a garden, that there must be 133,000 worms in one hectare of land, or 53,767 in an acre. There may be fewer worms in a field - maybe half as much. Then again, it depends what you class as a worm. There are many types of worms and they can be found absolutely everywhere on earth - in fresh water, seawater, soil and the bodies of plants and animals. Each group of worms has a vast number of species - for example there are more than 90,000 species of Nematoda - tiny threadworms called nematodes, too small to see clearly without a microscope. Some are useful, eating bacteria or killing insect pests and so on, while others do a lot of harm to the roots of crops. Therefore, there will be more than 100 million in an average acre of farmland.

[incitatus]

but then again you have to take into account soil variations. And sample validity....think about it, if you got lucky and picked up the one shovelfull of soil that was hosting the worm mardi gras, you would overestimate. Or if you erred to the other extreme you might have a field that is 90% worm and not know it. I think the only accurate way of estimating is probably to seive the entire piece of ground....

[eram]

At school we used to put a metre-square wooden frame over a piece of soil and pour DILUTE potassium permanganate in the area The worms then rush to the suface and you can can count them. But I seem to recall we had to quickly wash the worms in clean water after wards because the solution was harmful to them.