Jun 09 2010
Soil Conservation: A Matter of Life and Death, Part 4
In Part 3 I left off with talking about herbicides and how they affect the soil physically. Part 1 touched briefly on the knowledge expressed in the metaphors of Polynesian mythology, where the soil is pictured as the domain of a cyclical process in which death and decay turns into new life, which eventually dies and decays, and so on it goes. The point I”m making with this analogy is to show how certain kinds interventions in these processes reverberate through the chain and have disastrous consequences for soil retention and fertility. And of course armed with this insight we will be able to implement practices that actually help.
The two sides of this coin are like yin and yang, feminine and masculine, etc. The two of them together is what makes life in this world possible. Take away or change one of them, and the whole system collapses. If you constantly remove all decaying organic matter to get a “clean” look, the soil becomes unable to sustain life. Chemical “fertilizers” do not fulfill the same biological function and therefore cannot restore or maintain soil fertility in such a situation.
Herbicide application can overload the decay cycle with a sudden burst of dead plants that need to be processed. In the field, this often results in a very brief spike in nitrogen production followed by a steep decline. Not a recipe for healthy crops or landscape plants. The beneficial microbes, worms, insects, and other organisms that live in the soil are disrupted and often killed both by direct contact with the applied toxins and by such artificially induced swings in the nutrient balance. Also, because large parts of weeds killed by herbicides tend to remain standing up for long periods of time, they decay by weathering instead of being incorporated into the soil. This is a radically different process in which most of the nutrients contained in those parts end up in the air and are lost to the soil.
It is clear that in order to achieve and conserve optimal soil fertility, vitality, and retention, any cultural measures undertaken must support and enhance rather than disrupt the natural background processes taking place in the soil. A simple principle you can bear in mind as a guideline is: “Feed the soil life, not the plants. The soil life will feed the plants.” In other words, find out what the soil needs for ITS health, and cater to that, and you”ll be able to leave it to the soil to cater to the needs of the plants. How can this principle be put into practice?
- As already mentioned, avoid herbicides, chemical fertilizers, and any other substances that harm the life forms that inhabit the soil.
- Work rock dust or sand made from crushed rock into the soil. This is a way of adding mineral nutrients that doesnt”t circumvent or disrupt, but actually enhances the natural soil processes.
- Avoid using fresh chipped tree waste mulch, especially that of the usual medium size. It sucks all the nitrogen out of the soil and forms a shingle-like surface that makes the rain run off it. Extra finely chipped tree waste can be composted together with a high-nitrogen waste such as chicken manure. Very course chip – chunks of several inches long – can be spread very thinly or placed in small piles in woodland landscapes.
- Space plants as closely as possible without crowding them. Wherever plantings need to be widely spaced and leave patches of soil bare and weed-prone, plant soil-improving ground covers, e.g. clovers, in between.
Beside helping to prevent erosion, these measures also dramatically improve plant health, and in the case where the plants grown are food crops this translates into copious yields of foods with much higher nutritive value than their counterparts grown in dead or no soil. This in turn obviously promotes human health, and so the cycle goes round.





