Monday, October 23, 2006
Plants With Stomachs - Peak Oil Implications
Feedback that got on a recent presentation of mine has, most unfortuntely, reminded me that the average person does not even a basic understanding of natural plant nutrition. Nor do they understand what soil fertility is, or what affects soil ferility. Most importantly, and this is where it is unfortunate, people generally do not understand the dire implications for our future global food security if we pass peak oil and head down the downslope of oil depletion without first taking strong remedial action to restore soil fertility, most particularly on those soils that have been used for commercial agriculture over this past half century.
How do plants get their nutrition and what nutrition do they need? I am guilty of having thought that was a simple question to which most people would instinctively know the answer. I was so very wrong.
Plants, of course, get their air from the same place we do.... from the atmosphere. But they, of course, do not breath air to get oxygen. They are after the carbon dioxide and after they are finished with they "exhale" oxygen, the direct opposite of ourselves. Does the destruction of the Amazon rain forest affect our global air quality? You bet your ass it does. Does it affect the build-up of greehouse gasses that is contributing so heavilly to global warming? Absolutely. Does it affect the nutritional quality of those plants we grow for food? Most people do not seem to realize that it does. The more carbon dioxide there is in the atmosphere the more plants will grow. To so many that is a good thing. The unfortunate reality is that the nutritional content by volume that results from that extra growth is going down steadilly. The other little understood reality is that, just as pure oxygen is toxic to our systems, the higher the concentrations of carbon dioxide in the atmosphere the more injurious it is to many plant species. They have, after all, evolved in an environment with a very tight range of CO2 concentration in the air they breath. When the concentration is outside those limits they can't cope with it any more than we can.
Plants, for the most part, get their water from the soil in which they grow. One of the key properties of naturally fertile soil is its ability to hold water which is then available to the plants growing in it. That water retention facility is a result of organic matter and humus in the soil. It is also a function of size of soil particles and the population of micro-organisms in the soil. Soil depleted of its organic matter and humus, soil where critical micro-organisms have been killed by pesticides and other petrochemicals, loses its ability to retain water. We compensate by irrigating those crops. This further exacerbates the problem by leaching critical nutrients, most particularly minerals, down into the sub-soil, and by building up toxic salts in the top soil that are injurious to both the micro-organisms in the soil but also to the plants grown in it. Those plants, for example, that extract nitrogen from the air and fix it in the soil are seriously affected by these toxic salts. The bacteria responsible for building the nodules on the roots of these plants wherein the nitrogen is held are very adversely affected and killed by the build-up of soil salts. No problem. We simply add nitrogenous fertilizer to the soil to make up for the inability of these soil organisms to fix nitrogen from the air. These heavy concentrations of inorganic nitrogen, however, simply make the problem worse over time because neither the soil organisms or the plants can cope with the overload.
Some of the most interesting feedback and discussion I received following my presentationwas about my point that, unlike ourselves and other animals, the mouth, stomach and digestive system of plants is not inside the plant but is, in fact, in the soil in which the plant grows. We eat whole foods which are broken down into discrete nutrients by the bacteria, enzymes, and other micro-organisms contained within our stomach and other parts of our digestive tract. Nutrients enter our bloodstream in pure form after being broken down. For plants all of that activity takes place in the soil. In healthy soil there are millions of these "digestive" micro-organisms for ever cubic inch of soil. A majority of them, in fact, live in a narrow zone surrounding the roots of the plants, and nowhere else. They break down and convert the organic and mineral nutrients in the soil into a form that the the plants can utilize. Pouring on chemical fertilizers is an extremely inefficient way of trying to feed plants. It still requires enzymes and bacteria in the soil to transform the nutrients into a bio-available form and make it available to the plant's roots. A great deal of the fertilizer introduced synthetically never gets taken up by plants. It either builds up to toxic levels in the soil or gets washed away into our rivers and lakes to pollute them. We continue to use more and more artificial fertilizer on commercial agricultural soil every year and yet our crop yields continue to decline. I have seen figures, and I can't validate them, that we are using 33 times as much fertilizer per acre today than just 35 years ago and yet are faced with crop yields of 20% less or worse.
The point in this rant is this. The green revolution championed by Doctor Norman Borlaug, which is based on the use of petrochemicals, irrigation, and high-yield hybridized anf GMO seeds, allowed us to head off a serious human calamity being brought about by overpopulation last century. Through the green revolution global food grain production more than doubled over this past half century. The problem is that the global population increased in the same time by an even greater percentage. Once we pass peak oil and agrcultural petrochemicals become, at first, increasingly expensive and then increaingly unavailable, the artificial fertilty that our use of petrochemicals has allowed will be lost and we will have to return to a dependence on natural soil fertility. The problem then is that the natural soil fertility on which we will then rely does not exist. We have destroyed it over this past half century. It will take at least two decades to restore that natural soil fertility no matter what method we use. With our artificial soil fertility gone and our natural soil fertility decades away, global food production capacity will fall to dramtically low levels. Naturally fertile soil, properly managed, can produce significantly higher polyculture crop yields than chemically dependent monoculture. The only problem is there is so little naturally fertile soil left on which to do it.