life.  Great care must be taken to prevent it from getting into waterways.  In the tropics, people traditionally harvest great quantities of fish by tossing a handful of powdered derris (a root containing rotenone) into the water, waiting a few minutes, and then scooping up stunned, dead, and dying fish by the ton.  Rotenone is also deadly to earthworms.  However, rotenone rarely kills worms because it is so rapidly biodegradable.  Sprayed on plants to control beetles and other plant predators, its powerful effect lasts only a day or so before sun and moisture break it down to harmless substances.  But once I dusted an entire raised bed of beetle-threatened bush bean seedlings with powdered rotenone late in the afternoon.  The spotted beetles making hash of their leaves were immediately killed.  Unexpectedly, it rained rather hard that evening and still-active rotenone was washed off the leaves and deeply into the soil.  The next morning the surface of the bed was thickly littered with dead earthworms.  I’ve learned to treat rotenone with great caution.

Microbes and Soil Fertility

There are still other holistic standards to measure soil productivity.  With more than adequate justification the great Russian soil microbiologist N.S.  Krasilnikov judged fertility by counting the numbers of microbes present.  He said,

“. . soil fertility is determined by biological factors, mainly by microorganisms.  The development of life in soil endows it with the property of fertility.  The notion of soil is inseparable from the notion of the development of living organisms in it.  Soil is created by microorganisms.  Were this life dead or stopped, the former soil would become an object of geology [not biology].”

Louise Howard, Sir Albert’s second wife, made a very similar judgment in her book, Sir Albert Howard in India.

“A fertile soil, that is, a soil teeming with healthy life in the shape of abundant microflora and microfauna, will bear healthy plants, and these, when consumed by animals and man, will confer health on animals and man.  But an infertile soil, that is, one lacking in sufficient microbial, fungous, and other life, will pass on some form of deficiency to the plants, and such plant, in turn, who pass on some form of deficiency to animal and man.”

Although the two quotes substantively agree, Krasilnikov had a broader understanding.  The early writers of the organic movement focused intently on mycorrhizal associations between soil fungi and plant roots as the hidden secret of plant health.  Krasilnikov, whose later writings benefited from massive Soviet research did not deny the significance of mycorrhizal associations but stressed plant-bacterial associations.  Both views contain much truth.