Chapter 6 Kingdom of the Five Soils

The thin layers of soil that cover the continents like patches control the existence of us humans and the various animals that live on the land.As we know, land plants cannot grow without soil, and animals cannot live without plants. If it is true that our agriculture-based life still depends on the soil, it is equally true that the soil also depends on life; the origin of the soil itself and the natural characteristics it retains are intimately related to living animals and plants .For soil is in part a creation of life, born of a strange interaction between living and nonliving things long ago.When volcanoes blast fiery streams, when water rushing over the bare rocks of land wears away even the hardest granite, and when freezing temperatures crack and break rocks, the primordial soil-forming material begins to gather.Then the creatures began their miraculous creations, turning this lifeless matter into soil little by little.The first covering of rocks, lichens, used their acidic secretions to facilitate the weathering of rocks, thereby creating habitats for other life.Mosses persist in tiny spaces in primordial soil made up with the help of detritus of lichens, shells of tiny insects, and fragments of a range of animals that originated in the sea.

Life creates the soil, and living matter in its extraordinary abundance exists in the soil; otherwise, the soil would be a dead and barren thing.It is precisely because of the existence and activities of countless organisms in the soil that the soil can give the earth a green coat. Soil is in a never-ending cycle that keeps it in a constant state of change.As rocks weather, as organic matter decays, and as nitrogen and other gases rain down from the sky, new matter is continually introduced into the soil.At the same time, other substances are taken from the soil, which are borrowed by living organisms for temporary use.Subtle, very important chemical changes are constantly taking place in a process in which elements from the air and water are converted into forms suitable for use by plants.In all these changes the living organism is always an active participant.

Few studies are more puzzling, and more easily overlooked, than the question of unearthing the vast numbers of creatures that inhabit the dark realm of soil.We also know only a little about the mutual constraints of soil organisms and the constraints of soil organisms with the subsurface environment and the aboveground environment. The smallest organisms in soil and possibly the most important are those bacteria and filamentous fungi that are invisible to the naked eye.They have astronomical statistics, a teaspoon of topsoil can contain billions of bacteria.Despite their tiny size, the total weight of bacteria in a foot of topsoil on an acre of fertile soil can amount to as much as a thousand pounds.The filamentous actinomycetes are slightly less numerous than bacteria, but because of their larger size, their total weight in a given amount of soil is still about the same as bacteria.Tiny bodies of green cells called algae make up the microscopic plant life of soil.

Bacteria, fungi, and algae are the main causes of decay in animals and plants, and they reduce the remains of animals and plants to the inorganic substances of which they are composed.Without these tiny organisms, the giant cycles of chemical elements like carbon and nitrogen through soil, air, and living tissue would not be possible.For example, without nitrogen-fixing bacteria, plants would have difficulty getting nitrogen even though they were surrounded by a "sea" of nitrogen-containing air.Other organisms produced carbon dioxide and formed carbonic acid, which facilitated the breakdown of rocks.There are other microorganisms in the soil that facilitate the various oxidation and reduction reactions by which minerals such as iron, manganese, and sulfur are transferred and brought into a state that can be absorbed by plants.

Also present in surprising numbers are tiny mites and primitive wingless insects called leaptails.Despite their small size, they play an important role in removing dead leaves and helping to slowly convert forest floor debris into soil.It's almost unbelievable what some of these little creatures have in accomplishing their tasks.For example, several species of mites are able to start their lives even in fallen fir-tree needles, hiding there and digesting the inner tissues of the needles.When the mites have completed their evolutionary stages, the needles are left with only an empty shell.The truly astonishing work in dealing with the litter of a great many deciduous plants belongs to the small insects in the soil and on the forest floor.They macerate and digest the leaves, and cause the decomposed material to mix with the topsoil.

In addition to this large group of very tiny but hard-working organisms, there are of course many larger organisms. The life in the soil includes all organisms from bacteria to mammals.Some of these are permanent inhabitants of the dark strata, some hibernate or pass certain stages of their life cycle in subterranean burrows, and some move freely only between their burrows and the world above.All in all, the result of the activities of these inhabitants in the soil is to fill the soil with air and to promote the drainage and infiltration of water throughout the plant growth layer. Of all the large inhabitants of the soil, perhaps none is more important than the earthworm.Three-quarters of a century ago, Charles Darwin published a book entitled "The Formation of Crop Loam by the Action of Worms and Observations on Worm Habits".In this book, Darwin made the world understand for the first time the fundamental role of earthworms as a geological force in transporting soil—bringing before us a picture of the gradual transformation of surface rocks by earthworms from The ground is covered with fertile soil which, in the best districts, may be removed in quantities of many tons per acre each year.At the same time, large amounts of organic matter contained in leaves and grasses (as much as 20 pounds per square meter in six months) are drawn into the burrows and mixed with the soil.Darwin's calculations showed that the labor of earthworms could thicken the soil layer inch by inch and make the original layer thicker by half in ten years.That's not all they do, though; their burrows fill the soil with air, keep it well-drained, and encourage plant root development.The presence of earthworms increases digestion by soil bacteria and reduces soil spoilage.Organisms are broken down through the digestive tracts of earthworms, and the soil is enriched with the help of their excrement.

However.This soil complex is made up of an interwoven web of life where one thing is related to another in some way - the living beings are dependent on the soil, and in turn only when the life complex is thriving, the soil to be a living part of the earth. Here, too little attention has been paid to our concern whether applied directly to the soil as a "disinfectant" or brought by rain (when have been fatally polluted], in short, when toxic chemicals are introduced into the world of soil-dwellers, what will happen to these enormously beneficial soil organisms? For example, Suppose we could apply a broad-spectrum insecticide to kill the larvae of burrowing, crop-damaging pests, is it reasonable to assume that it would also not kill the "good" bugs that are capable of decomposing organic matter? Or, could we use a Can a non-specific fungicide be used without harming other fungi that exist in beneficial symbiosis on the roots of many trees and help trees absorb nutrients from the soil?

Soil ecology, an extremely important scientific subject, has apparently been largely ignored even by scientists, and almost completely ignored by managers, and chemical control of insects appears to have been based on such an assumption This is done on the grounds that the soil really can tolerate insults that introduce any amount of poison without revolting.The natural nature of the soil world has been neglected. From the few studies that have been done, a picture is slowly unfolding about the effects of pesticides on soil.These findings are not always consistent, which is not surprising because soil types vary so much that what causes damage in one type of soil may be harmless in another.Light root root sand is far more severely damaged than humus.Combinations of chemicals appear to be more harmful than individual ones.Regardless of these discrepancies in results, sufficient and reliable evidence on the dangers of chemicals is accumulating, and in this regard many scientists are uneasy.

In some cases, chemical transformation processes central to the living world have been affected.Nitrification, which converts atmospheric nitrogen into a form available to plants, is an example.The herbicide 2.4-D can temporarily interrupt nitrification.In several recent experiments in Florida, hexachloride, heptachlor, and BHC (hexachlorobiphenyl) reduced soil nitrification after only two weeks of application: The severe deleterious effects were maintained for a year after application.In other experiments, HC, aldrin, HC, heptachlor, and DDD all prevented nitrogen-fixing bacteria from forming the root nodules necessary for legumes.The wonderful and beneficial relationship between fungi and the roots of higher plants has been seriously disrupted.

The problem is that sometimes this delicate balance is disrupted. Nature depends on a delicate balance of biomass for its far-reaching purposes.When some species of organisms in the soil are reduced by the use of pesticides, other species grow explosively in the soil, disrupting feeding relationships.Such changes can easily alter the metabolic activity of the soil and affect its productivity.These changes also mean that previously repressed potential pests can escape from their natural control and rise to the status of nuisance. A very important thing to remember when considering pesticides in soil is that they become entrenched in the soil not on a monthly basis but on a yearly basis.Aldrin was still found four years later, partly as trace residues, and more partly transformed into dieldrin.Ten years after using toxaphene to kill termites, large amounts of toxaphene remained in the sand.HC6 can persist in soil for at least eleven years; heptachlor or its more toxic derivatives can persist for at least nine years.Fifteen percent of the original weight was found to remain in the soil after 12 hours of application of chlordane.

It appears that years of controlled use of pesticides can still build alarming levels in the soil.Since chlorinated hydrocarbons are stubborn and permanent, each application adds up to the amount originally held.The old saying that "one pound of DDT per acre is harmless" is empty talk if spraying is repeated.DDT was found in soils in potato fields at 15 pounds per acre and in corn fields at 19 pounds.One cranberry swamp studied contained 34.5 lbs. of DDT per acre. Soils taken from apple orchards appear to have reached the highest levels of contamination; here the rate of DDT accumulation has grown in step with annual use. with.DDT residues can peak at 30 to 50 pounds per acre even in one season, as a result of four or more DDT sprays in orchards.If sprayed continuously for many years, the area between trees will contain 26 to 60 pounds of DDT per acre, and the soil under trees as much as 113 pounds. Arsenic provides a famous example of how soil can indeed be permanently poisoned.Although arsenic as a spraying agent on tobacco plants has been largely replaced by man-made organic synthetic insecticides since the mid-1940s, arsenic levels in cigarettes made from U.S.-grown tobacco decreased in 1932 In 1952, it still increased by more than 300%.Recent studies have revealed an increase of 600%.Dr. H. S. Sitley, an authority on arsenic toxicology, said that although organic pesticides have largely replaced arsenic, tobacco plants continue to absorb arsenic because the soil where tobacco is grown has now been completely destroyed by a large, A less soluble poison, impregnated with residues of lead arsenate.This lead arsenate will continuously release arsenic in soluble form.According to Dr Sitley, the soils of a large percentage of the land where tobacco is grown have suffered from "multiplicative and almost permanent poisoning".Tobacco grown in eastern Medeltrana, where arsenic pesticides have not been used, has shown no such increase in arsenic levels. Thus, we are faced with the second problem.Not only do we need to be concerned with what happens in the soil, but we also try to know how much pesticide is being absorbed into plant tissue from contaminated soil.This largely depends on the soil, the type of crop as well as the natural conditions and the concentration of pesticides.Soils with more organic matter release less toxic amounts than other soils.Carrots are taller than their native soil.In the future, it will be necessary to analyze the soil for pesticides before flushing some food crops, otherwise even unsprayed grains may pick up enough pesticides from the soil to render them unsuitable Supply the market. The problems with this pollution are so endless that even the director of a children's food factory has been reluctant to buy fruit and vegetable pods that have been sprayed with toxic pesticides.The most irritating chemical was the 6-6-6, absorbed by the roots and tubers of the plant, which imparted a musty taste and smell.The sweet potatoes on the land in California had been treated with BCH two years ago, but now they had to be discarded because they contained BCH residues. One year a company in southern Keolina signed a contract to buy all of its sweet potatoes. When it was discovered that large areas of the land were contaminated, the company was forced to go back to buying sweet potatoes on the open market, this time at great financial loss. .After a few years, many varieties of fruits and vegetables grown in many states also had to be discarded.Some of the most vexing problems are related to peanuts.In some southern states, peanuts are often rotated with cotton, which is widely used on cotton fields.Peanuts grown on this soil subsequently absorbed considerable amounts of the pesticide.In fact, just a little bit of 666 can smell its musty smell that can't be concealed.The chemical seeps into the pit and cannot be removed.The treatment process does not remove the musty smell at all and sometimes intensifies it.For a business operator who is determined to eliminate H66 residues, the only way he can use is to throw away all agricultural products that have been treated with chemicals or grown on soil contaminated by chemicals. Sometimes the threat is the crop itself—a threat that has always been there as long as there was pesticide contamination in the soil.Some pesticides affect sensitive plants such as beans, wheat, barley, and rye, hindering root development and inhibiting seed germination.The experience of the hop growers in Washington and Edward is an example.In the spring of 1955, many hop growers undertook a large-scale program to control strawberry root weevils, whose larvae had become excessively numerous.Under the advice of agricultural experts and pesticide manufacturers, they chose heptachlor as the control agent.During the year following the application of heptachlor, the vines in the treated plots withered and died.There were no incidents in the fields not treated with heptachlor, and the limit of crop damage was at the border between treated and untreated fields.So I spent a lot of money and replanted crops on the hillside, but found that the newly grown roots were still dead in the second year, and there was still heptachlor in the soil four years later, and scientists could not predict the toxicity of the soil. No matter how long it will last, there is no way to improve the situation.It was not until March 1959 that the Federal Agricultural Office discovered its wrong position on this soil treatment issue in announcing that heptachlor could be applied to winemaking plants, and retracted it too late.Meanwhile, hop growers are left to seek compensation in the lawsuit. Pesticides continue to be used, and indeed persistent residues continue to accumulate in the soil, and there is little doubt that we are heading for trouble.This was the unanimous opinion of a group of experts meeting at the University of Enrkas in 1960 to discuss soil ecology.These experts summed up the hazards of using "such potent but poorly understood tools" as chemicals and radioactivity: "Some mishandling on the part of man may have Arthropods are fine."