Plants Create Soil

Driving along California’s Highway 1, looking up at the cliff along the road cut, I saw sand, gravel, and rocks, that yellow-tan called buff, all dead; but on top of it, the top foot or so, there was dark soil, brown, almost red, and on top of that, plants. And I had a sudden realization: plants create soil.
When we want to grow plants, we think we have to prepare the soil for them. We till the soil to break it up, and we get mulch and fertilizer and topsoil so our gardens will be fruitful. Even the Bible talks of the futility of casting seeds on unfertile ground. But in the natural world, plants prepare the soil for themselves.
In barren lands, seeds fall on the rock and sprout anyway. Their young roots find tiny cracks in the rock, and force their way into them. They grow and exert pressure to expand the cracks. Rain, dew, mist, water flows into the cracks and nourishes the roots. The roots express chemicals that break the rock down, weakening the rock, and releasing raw materials for the plants’ growth. Leaf litter, bits of bark, dust fall and blow into the crack, bringing more nutrients and encouraging the roots to expand and make more room. Other small plants, and fungi, join in. Tiny animals also move in and contribute to the general degradation of the rock. And when the root dies, it provides more organic material for the next seeds that fall into the crack.
Over time, rocks split into landscape, and into gravel, into sand, and with the addition of more and more dead plant material, into soil. That foot of dark atop the rocks in Big Sur, that topsoil you buy by the bushel at the garden store, that soil has been created, not by humans, but by plants.

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