by Malcolm Beck
Too much Carbon Dioxide (CO2) in the atmosphere is believed to be causing global warming, upsetting our good weather patterns, and dooming our present lifestyle. Most often the problem is blamed on our practice of burning fossil fuels, but there are other pollution sources and solutions.
A thinking scientist once calculated that if we increased the organic content of our farmlands just 1/10 of one percent each year, it would offset all CO2 produced by burning fossil fuels. Using soil as a carbon sink is an excellent idea, and one that takes care of multiple problems. It gets rid of carbon and adds needed carbon to the soil.
At one time, all land suitable for tillage in the U.S. had an organic content of 3 to 8 percent. Today the organic content of our tillable soils is very low. The Rio Grande Valley, the third largest produce-growing area in the U.S., had an organic content of 3 to 5 percent when agriculture first started in the area. The original farmers found the soil rich and had no need for fertilizers, irrigation or pesticides. Today most of the Valley is at ½ percent or less organic matter in the soil, and the cost for irrigation, pesticides, and fertilizers is around $1,200 per acre each year.
Where did the carbon from all the lost organic matter go? If we weighted the excess carbon in the air, it would probably equal the lost carbon from our farm lands.
Over-tillage is one of the causes of many agricultural problems. Tilling allows more oxygen in the ground than Nature intended. Plowing too often and too deep activates the microbes causing them to feed on the organic materials faster than Nature wants. Their digestion releases CO2 to the air, just as the digestive processes of humans and animals creates CO2.
Dr. Joe Bradford, USDA ARS, has been researching minimum till farming for many years. In his research, he is seeing the South Texas soil organic content go up, cotton root rot disappear, and crop production increase. In non-irrigated areas, he has farmers taking money to the bank, while their conventional, over-tilling neighbors have crop failure.
There are other and worse methods of modern agriculture that creates excess CO2 in the air. When I started operating my own farm organically, the local agricultural extension service laughed at me. They said it made no difference if you used organic or chemical fertilizers because the microbes had to process it into the ion form before the plants could properly use the nutrients anyway. They are correct about that. However, they forgot a law of physics. Nothing can happen or start in motion without a source of energy.
Chemical fertilizers contain no energy, have few minor and trace elements, and usually are in poor balance. They have a high salt index that can harm plants if soil moisture is low. With rain or irrigation, they may be too soluble and leach past the roots without giving the plants a chance to absorb them.
The biggest, and unrecognized, problem with the high-analysis chemical fertilizers is their lack of energy. The microbes that live in the soil are forced to draw on the soil's energy to process the chemicals. Chemical fertilizers work when there is ample soil energy, but when energy runs low, chemical fertilizers can't perform efficiently. As a result, the farmer pours on more fertilizer, requiring still more energy. Soon the soil humus reserves are depleted, soil structure is lost, water insoak becomes less and less, water wells dry up, and when rains do come, flooding occurs causing soil erosion. During dry spells, there are dust storms because the crumb structure of the soil is lost. The poor, depleted soil is either washed away if it rains or blows away if it is dry.
Lack of humus and proper soil structure causes plants to become stressed. Stressed plants are prime targets for pests and diseases to strike. That, of course, leads chemical farmers to add more chemicals, mostly toxic. These chemicals also attack the necessary microbes and other soil life. Some die and soil structure is damaged still further.
Because of these poor farming practices, the state of California alone is gaining 10,000 acres of desert annually. Worldwide, the productive soil loss is more than 25,000 acres every day of the year.
Organic fertilizers are naturally low in total N.P. & K, but since they come from once-alive things, they contain a balance of what is necessary for the next generation of life, mainly a high percentage of carbon in the form of carbohydrates, an excellent source of energy for the soil life. Decaying organic materials build a good soil structure that allows proper oxygen-CO2 exchange, increases the ability of soil to absorb rainfall, increases soil water holding ability with an increased cation exchange capacity, which prevents nutrients from leaching away and being lost.
The decay of organic matter in and on the soil is greatest during the warm, moist seasons when plant growth is also greatest. As the soil life degrades organic materials, an abundance of CO2 is released. Some of it mixes with water and forms carbonic acids to help dissolve minerals from the rock in the soil. But most of it escapes to the air. Since CO2 is heavier than air, it tends to remain close to the soil until it defuses with the air. As it drifts under the canopy of plants, it is captured by the pores (stomata) which are mostly on the underside of plant leaves. The plant leaves use energy from the sun to separate the carbon from the oxygen. The oxygen is released, but the carbon is made into carbohydrates that contain the sun's energy. >From this, all other life forms get their energy and oxygen.
The release of CO2 under plants instead of into open air is most important. When there is a concentration of CO2 in the air, the stomata can stay closed a high percent of the time. They open only to get carbon. If there is plenty in the air, they quickly get a mouthful and then quickly close and stay shut much longer. When they are open they are constantly losing moisture, causing a greater moisture draw from the soil. When closed, the stomata are conserving soil moisture. NASA scientists studying global warming discovered there is only two degrees difference in the leaf temperature between open and closed stomata. Thus the old belief that plants need to transpire to stay cool is not true.
Planet Earth is nearly 80 percent water and ice. The rest is dry land, but only about 8 percent is suitable for crop production. All life on earth is sustained by a thin layer of top soil. The quality of life on earth is determined by the quality of the soil. The quality of the soil determines the quality of the air we breathe, the water we drink and the food we eat. If we allow that thin layer to degrade to any degree, all life on earth degrades to the same degree.
Man's future and well-being on Earth depends on our understanding that...
Fertile healthy topsoil is created by decaying organic matter and decaying rock. They both must be present at the same time. Our mental health as well as our physical health is determined by the health of the soil.