The story of soil is a complex, intriguing one. Our project draws to us people, resources, and opportunities to uncover more facets of its nature. So we’ve decided to start collecting notes about things that surprise us here – notes on soil. Here we post new facets of our world’s soil body when the inspiration strikes us (sometimes literally~).
Oftentimes, when we talk about making soil, soil scientists point out that soil takes a long time to form. Yet as Dr Christine Jones mentions, in an interview, the building of topsoil versus the weathering of rock are two different phenomena, and human activity changes the speed at which they occur.
“the flow of liquid carbon to soil is the primary pathway by which new topsoil is formed“
Read about her work – and Amazing Carbon, here., or read extracts of her work below.
ACRES U.S.A. You’ve written that the most meaningful indicator for the health of the land and the long-term wealth of a nation is whether soil is being formed or lost. Yet there’s a widespread belief, actually dogma, that the formation of soil is an exceedingly slow process. Even some organic researchers accept that idea. You describe the formation of topsoil as being breathtakingly rapid.
DR. CHRISTINE JONES. People have confused the weathering of rock, which is a very, very slow process, with the building of topsoil, which is altogether different. Most of the ingredients for new topsoil come from the atmosphere — carbon, hydrogen, oxygen and nitrogen
ACRES U.S.A. Why have many soil scientists denied the phenomenon of rapid soil-building?
JONES. Because they do their research in places where it’s not happening, where the carbon is running down and the soils are deteriorating. We need to measure carbon on farms where soil-building is occurring and see what the farmers and ranchers are doing to make that happen.
JONES. Liquid carbon is basically dissolved sugar. Sugars are formed in plant chloroplasts during photosynthesis. Some of the sugars are used for growth and some are exuded into soil by plant roots to support the microbes involved in nutrient acquisition.
ACRES U.S.A. I remember bringing up the idea of leaky roots in a conversation with you and you laughed.
JONES. At first people thought “leaky” roots were defective. Exuding carbon into the soil seemed such a silly thing for plants to do! Then it became recognized that some of the exudates were phenolic compounds with allelopathic effects, important in plant defense. …. perhaps the most significant finding, at least from a human perspective, is that the flow of liquid carbon to soil is the primary pathway by which new topsoil is formed.
ACRES U.S.A. All of which revolves around the concept of a plant-microbial bridge?
JONES. In order for carbon to “flow” to soil, there has to be a partnership between plant roots and the soil microbes that will receive that carbon. Somewhere between 85 to 90 percent of the nutrients plants require for healthy growth are acquired via carbon exchange, that is, where plant root exudates provide energy to microbes in order to obtain minerals and trace elements otherwise unavailable. We inadvertently blow the microbial bridge in conventional farming with high rates of synthetic fertilizers or with fungicides or other biocides.
A soil test will only tell you what is available to plants by passive uptake. The other 97 percent of min- erals — made available by microbes — will not show up on a standard test. By looking after the microbes in the soil we can increase the availability of a huge variety of minerals and trace elements — most of which are not even in fertilizers.
Read about her work – and Amazing Carbon, here.