Problems of Quality in the Productivity of Agricultural Land

In the discussion of our natural resources and processes, guidelines are essential. The usual quantitative characterizations of land contribute little to suggest the quality of agricultural products that may be grown on it. To say that the earth has two and a half billion acres of tillable land means little until equated against the earth’s human population of some three billion inhabitants. This tells us that each of us has, in the mean, something less than an acre of arable soil for growing food. The productive quality of one acre of the earth’s surface, in terms of its yield of protein in life forms and foods required by them, becomes far more significant than its quantity as mere surface area. The significance of soil quality is made clear when we realize that an acre does well to grow the beef equivalent to the present meat consumption per person per annum in the United States.

The term “meat” may well represent all living and self-multiplying substances characterized by their protein content. Proteins are provided for us in high concentrations in animal tissue, or in animal products which have food value for other forms of life: milk, cheese, eggs, and so on. Our thinking progresses from the quantitative to the qualitative, from the amount of land in acres to the productive capacity of the soil, and then to what it grows in terms of quality in nutrition for healthy survival, which becomes the criterion of quality in production.

Dimensional descriptions of the soil tell us little of its biological importance. They fail to bring this unique natural resource into focus as a dynamic natural substance that takes its origin from the lifeless inorganic rock minerals at the earth’s surface. Our quantitative evaluations of soil have, to date, not brought about sufficient appreciation of the soil to assure its conservation. But when we remind ourselves that the soil determines the biosynthetic processes of all that is organic and lives on a given area, its third dimension–the depth of fertile surface horizons in the profiles of rock fragments and organic matter, weathering and decaying under climatic forces–becomes highly important. A fourth and fifth dimension are important also: time, in eras and centuries; and energy, and its transfer finally into heat to escape into space, in accordance with the second law of thermodynamics. The combination of all five dimensions emphasizes the qualitative and dynamic aspects of the soil in the support of life, including the exhaustion of its fertility, its possible renewability, and its potential support of the different trophic levels, or life forms, in the entire biotic pyramid built up by, and dependent on, the soil.

As another emphasis on quality in production for the support of life we shall consider the soil, not so much for its role in giving us carbohydrates and fats as energy foods, but rather for its support of the biosynthesis of proteins. The quality of proteins needs also to be considered according to their quantities, not of nitrogen measured by ignition, but of their constituent amino acids, each in the amount required for health by any living species.

For additional refinement of the concept of quality in the productivity of the soil, we may well consider the evolution and survival of each of the several species in their ecological array. That array may be interpreted as nature’s report on the natural biological assay for success by a given species in each soil area. By recognizing the special nutritional requisites of species, correlated chemically and biochemically with the soil properties in its geoclimatic setting as potential production of proteins, we can do much through our treatment of the soil to raise the quality of production. We can at least prevent ecological misfits or violations of the bioclimatic laws and bring about fuller accordance with them.

Surface Phenomena Give Soil Its Dynamic Qualities For Plant Nutrition

The simple fact that the soil is the surface layer of the earth makes it a unique resource. The surface aspect of every kind of matter became a part of basic science with the advent of colloidal chemistry, which deals mainly with “surface phenomena.” These represent the forces of concentration of any two kinds of matter at their interface or area of contact. In that concept, the surface of the earth, as a bit of cosmic dust in contact with the atmosphere, sets up the many forces concentrating into maximum densities the several components of the atmosphere, and likewise those of the soil, at the soil-air interface. The plants inserted there take advantage of all these for production of their vegetative mass and for survival.

The concept of the variation in climatic soil development as the major determinant of biotic geography is now coming to be accepted. The climatic pattern of soil development of the United States illustrates its operation. The increase in rainfall from the Great Basin eastward as far as the midcontinent brings increasing kinds and quality of vegetation as water weathers the rock into deeper soil with more clay and more fertility for plant nutrition through protein production. From the midcontinent eastward there is a reciprocal decline in protein production, although the clay content and its colloidal behavior increase. The monovalent cation, hydrogen, increases but the divalent cation, calcium, adsorbed on it, decreases.

With that decrease in adsorbed calcium of the soil, the percentage of calcium and of other cations in the dry matter of the vegetation decreases. But the relative decrease in calcium is much greater than that of other elements. Consequently there is a narrowing calcium-potassium ratio. The decline in protein production connected with the calcium is more rapid than in the carbohydrate production with which the potassium is related in the plant’s processes. Thus a shift from a semi-arid to a humid condition causes fertility depletion in the soil and decline in nutritional quality, especially in proteins and the inorganic essentials associated with them in the vegetation.

The same pattern of changing quality of vegetation according to the degree of soil development from and to moderate rainfalls and from moderate to excessive ones is seen in particular traverses in the Soviet Union; in Australia, in the changing qualities of wool; in Argentina, in grasses for growing and fattening grazing animals; in Hawaii, according to altitude rather than longitude and latitude; and in Java, according to recentness of volcanic eruptions.

Calcium, and its distribution in the profile, was the first index by which the soil surveyor correlated soil quality with rainfall and temperature. The student of crops mapped the virgin vegetation as grasses in the western parts of the midcontinent and as forests in the eastern parts. He spoke of prairie soils and forest soils. That led to the erroneous implication that the soil is the result of vegetation rather than the cause of it. The maps of animal production as patterns of protein potential of the soil show that high-protein animals, like cattle, are grown in the western midcontinent. But pigs, as pork, for speedy gain in weight through fattening procedures (abetted by castration) are grown in the eastern midcontinent. The highest percentages of land under cultivation are found in the midcontinent, where animal population densities are also at their maximum.

In the correlation between soil fertility for protein production and biotic geography, the former is the major cause, the latter the effect through soil chemistry and biochemistry. In maps of electrical transmission for radio reception, the “excellent” and “good” areas in the midcontinent almost mirror the map of soil fertility. Poor reception by radio correlates with minimal qualities of health and survival outside the midcontinent area.¹

When the atmosphere serves as one line of electrical transmission by wave for radio, and the soil is the other conducting line of the circuit, we need to be reminded that the soil will be a good conductor only when both moisture and electrically active ions of the fertility elements are ample. Neither water without the ions nor the latter as salts in a dry soil are effective conductors for radio reception. Nor will they provide the chemodynamic services in the soil’s production of quality feeds and foods. Ions serve in the soil, not as high concentrations in the salts of and and alkaline regions, but as elements of low degrees of ionization adsorbed on the soil colloids and remaining there in the face of higher rainfalls that leach salts out of the soil. We are slowly organizing the biochemical and ecological facts that prove the soil to be a prominent determiner of the quality of crop growth.

The better understanding of surface phenomena active within the soil has clarified our understanding of how soils can resist loss of nutrient elements to percolating waters, retaining them in ample supplies readily available to plants. The soil’s finer particles of clay represent enormous total surface in very small mass. Surface phenomena serve to concentrate, on and within the clay, some of the nutrient elements weathered out of the rocks. These are held by the clay against loss to percolating water. But those nutrient elements, although chemically insoluble, are nevertheless biologically available to plant roots. Through the weathering process of the reserve rock, inert, inorganic matter becomes creative according to its total exposed surface rather than to its quantity as weight. A shift in emphasis from static mass to dynamic surface shortens time and magnifies energy, thus emphasizing quality over quantity as a criterion of soil classification.

Grinding rock into particles no smaller than silt size (0.02-0.002 mm), carried and deposited by winds, gives sufficient increase of surface and of rate of weathering in contact with acid clay to improve crop growth.² The virgin silt soil (loess) of the midcontinent serves as a regularly renewed resource with its half-ton deposits per acre per year of unweathered minerals picked up from the winter-dry Missouri River bottoms and plains for deposition under higher rainfalls to the northeast. In this way the protein-producing potential of crops has been not only maintained but extended in area.

Plot tests on different sizes of limestone particles have demonstrated the extended nutritional service for the second year’s growth of sweet clover when the particles were nearer ten-mesh than hundred-mesh size. Larger particles, broken down by reacting with the clay, gave fewer foci offering calcium as plant nutrients, yet gave saturation to higher percentages of the soil’s adsorption capacity and thereby larger amounts for the nourishment of the roots. The smaller particles, providing more numerous foci in the soil and thus promoting the speedy adsorption of all the calcium, left the clay holding that element at high energies beyond the competitive power of the roots to remove it for plant nutrition in the second season. Gradual nutrient release by slow reaction rather than speedy delivery as in soluble form is a basic natural principle in the growing of high-quality agricultural products. It emphasizes nature’s use of rock fertilizers rather than soluble, highly concentrated salts for maintaining the soil as a resource for growing microbes and plants.

These facts support the concept that the soil need not be a uniform medium, but may well be a heterogeneous collection of foci of minerals or rocks weathering while in contact with clay and plant roots. Plant growth, then, is a summation of all these centers of fertility as the roots move to and get from them all that is needed for maximum quantity and quality, or fail accordingly. By this concept, both the more soluble and the less soluble nutrient materials applied in granular or fragmental forms will better maintain this seemingly beneficial heterogeneity of fertility sources than would any practices aimed at reducing the soil to the uniformity of nutrient solutions.³

Clay serves as the negative anion in the surface phenomena of adsorbing the positively charged elements (cations) such as hydrogen, calcium, magnesium, potassium, and the trace elements. Extensive tests of the retention of cations by soil colloids (clay and humus) have shown that the varying ratios of cations, in the total exchange capacity of the soil, are reflected in the varying chemical compositions and qualities of crops.

Of the cations or nutritive elements listed above, only hydrogen is not taken by the plant from the soil. Vegetation varies greatly both in total protein content and in its amino acid constituents according to the ratios or percentages of saturation of the colloids by the exchangeable cations. The ratios depend on the differing degrees of soil development as well as on many other factors. They provide a refined means for interpreting the diet offered to the plant by the soil. But there remains much of plant quality which surface phenomena will not interpret, however helpful that concept has been.

The chemical composition of soil may represent either a few or many inorganic elements of rock and mineral origin. Analytical inventory of soil elements by ignition is but a gross measure of the adequacy of inorganic nutrition for microbes, plants, and higher forms of Iife.⁴

Interdependence of Species Emphasizes Equilibria For their Natural Conservation

There are interrelations representing conservation between the several interdependent trophic levels. The remnants of any resource, the organic and inorganic wastes from one life form, may be the major resource of another in terms of matter and energy. That relation may be as intimate as symbiosis. Soil resources, comprised of varying geological matter weathered under differing climatic forces, must of necessity vary widely according to geographic location. Within limited areas the soil attains brief states of equilibrium which is characterized by a particular productivity. Over eras of time, the soil is never in more than temporary equilibrium while on its way to solution and to the sea. The potential productivity of the soil must then be variable with time. Its productive quality only appears to be a constant, as when we speak of it simply as “land.” Soils are the natural dynamic result of spending the innate and acquired energies of the earth which, like a wound-up clock, is in the course of running down.

To support microbial life, the lowest trophic level, the soil must provide the essential mineral elements and the organic substances which microbes oxidize for chemical energy, captured previously from the sun and stored by plants. Microbes are not equipped with chlorophyll, as are plants, to capture the sun’s energy for themselves. The microbe is a single-cell form that may be used to illustrate the principles applicable to multi celled bodies. Visualize any sterile soil inoculated with life by a single microbe. Assuming all the essentials available in the soil for the microbe, the numbers of the increasing population, plotted as ordinate against time as abscissa, will give the characteristic sigmoid curve. Its shape suggests an S with the top pulled to the right while the lower left end remains fixed. During the early stage, the population increase is geometric. It doubles per unit of time of cell division. But soon the shortage in the food supply and the accumulation of wastes operate against continued increase. These two factors give the second half of the curve, which is an inverted duplicate of the reversed first half.

Thus a simple laboratory illustration can demonstrate how any life form comes into a favorable setting, runs its course to climax or maximum, and then passes on to extinction. This occurs unless it is able to modify, advantageously, its own original physiological processes. But when microbes change, the nature of the soil is also changed to the extent that it can no longer serve as the growth medium for another similar population. It could, however, be such for other microbes with different but lesser requirements. But as producers these would deliver less quality in their product. That principle applies to the soil in relation to any and all of the different strata of life when each goes through the stages of introduction or establishment, increase or growth to a climax crop, and disappearance through the same factors, forces, and phenomena cited for the microbe. We are prone to see only the second period, the increase toward a climax crop.

The struggle by multicelled bodies duplicates, in principle, that by the microbe, since the former are the summation of many cells combined in a larger body. The soil microbe carries out oxidation and reduction, thus gaining or spending combined and stored energy, much of which escapes as heat. The resulting acids–carbonic, nitric, sulfuric, and many organic acids–becoming weathering agents of rock minerals, thus increasing the availability of their nutrient elements. Microbes, in a sense, carry out analyses and syntheses. Their growth becomes a highly differentiated cell division only when certain compounds trigger that self-multiplying phenomenon, which transcends the mere increase in mass by living tissue. The microbe illustrates the same principles which operate in all higher forms of life, fitting themselves into the environment and surviving by growth and multiplication in accordance with the fertility of the soil.

Because of their dependence on organic matter for energy, through decay or oxidation, microbes constitute the decomposer stratum in the biotic pyramid.They obtain their requirements for growth or tissue building from both the decaying organic debris and the decomposing minerals of the soils. Many of the essential elements and organic nutrient compounds remain in cycles of use and re-use, since sulfur, nitrogen, phosphorus, and carbon are major constituents in microbial left-overs.

Microbes may reproduce at the rate of one generation per hour or less. They synthesize extra- and intracellular compounds which protect them against competitors and predators. Those chemical compounds may serve as antibiotics for the human body. They may be considered an evolutionary (accidental) good fortune, a by-product of value from metabolic wastes of the microbe. From such, in response to hypodermic inoculations, the human body generates anti-bodies.

The production of antibiotics by microbes suggests that the biosynthesis of organic compounds by each life form may provide support to others. It certainly emphasizes their interrelations. This is suggested for plants also when gardeners speak of the compatibility and protection provided by certain crops for others when they are inter-planted. As decomposers and synthesizers of myriads of organic compounds, the microbes make for themselves an environment in what is often said to be a “living soil.” Thus nature practices conservation by using the wastes from a lower form of life to make the environment more compatible with its survival and, incidentally, that of other and higher species as well.

Man as a species hardly manages his own environment in such a way as to actively encourage the survival of other forms of life along with his own. Instead, he more often destroys the equilibria on which the other species depend for survival.

Human societies, however, are giving more thought and effort to the conversion of city wastes for re-use as fertilizer. Such measures may also serve to prevent pollution by the many complex organic compounds and dangerous inorganic compounds that are dumped directly by industry into streams. The flushing of organic substances from cities into streams and the sea has been needlessly depleting our soils. As a result, agricultural production has shifted to one of increased bulk and reduced nutrition. We easily forget that the return of organic matter to the soil is crucial in the maintenance of the quality of products now flushed into the sea. It must become a major effort if the decline in quality of production is to be checked.

Plants, as producers of stored energy, are a major part of the biotic foundation. They are the only significant producers, relative to quantities of stored energy, within the biotic arrangement. Like the microbes, they are unique in that their metabolic waste of carbon dioxide in water gives carbonic acid with ionic hydrogen, a non-nutrient cation within the soil that is adsorbed on the plant root. There it exchanges for the nutrient cations–calcium, magnesium, potassium, ammonium, and others–adsorbed on the colloidal clay and humus, and mobilizes them. Plants, as excretors of other acids and compounds, or as oxidizers and reducers, speed the breakdown of rocks and minerals into finer fragments to produce colloidal clay and thus make available the elements of fertility. Plants, much like the microbes, improve the environment for their own survival through addition to the soil of their wastes and by-products.

Plants are the producers for all life forms because they are nature’s means of storing and distributing, as foods, in usable chemical forms, the energy supplies imparted to the earth by the sun. Such energy is collected by the unique process of photosynthesis. This is brought about by means of the inorganic part of chlorophyll to help that enzyme combine carbon, hydrogen, and oxygen into the common energy food, the carbohydrates. These are the plant’s food for its own metabolism. In that respect, plants are the energy source not only for themselves but also for biochemical processes at various trophic levels.

Compounds of six carbons and their multiples or units near the figure six constitute most of the carbohydrates and the major part in the chemical composition of a plant’s dry matter. While carbohydrates represent high energy values, reduction or removal of oxygen from those compounds pushes their energy values even higher in the straight-chain hydrocarbons, suggesting fats, or in those of benzene, a six-carbon ring structure. While the human body metabolizes the former compounds of limited length, apparently it is unable to break the benzene ring, which the liver, kidneys, skin, and excretory system as a whole must accept as overload. Nor is the benzene ring broken readily by microbial metabolism. Hence it persists from wood and bark through coal and oil to be recovered by their destructive distillation.

Carbohydrates are also starter compounds for the plant (and microbe) into which its synthesis of nitrogen, sulfur, and phosphorus yields the amino acids constituting proteins as living tissues which grow, protect, and reproduce. Thereby plants, nourished by the soil and its microbial aids, are in one sense the only producers. They are the sources of both food energy and growth substances synthesized from chemical elements and passed on, as life support, for all other populations either higher or lower in the biotic pyramid.

In that schematic arrangement, the three lower strata of plants, microbes, and soil are the basic synthetic support of all living matter. The plants supply stored energy and growth substance. The microbes remove accumulated organic matter, and serve as salvage crews to return water and carbon dioxide to the atmosphere, and recycle the elements of mineral origin and many organic substances for nutrition of plants and themselves within the soil. Plants live in both soil and atmosphere. Microbes live very much within the soil. They were the first forms of life to appear. and will doubtless be the last to disappear. They are, however, often in symbiotic relationship with plants.⁵

Above these three, all life forms are, in the final analysis, dependent on the organic substances produced by plants and transformed mainly by simplifications at higher trophic levels. Were we able to catalogue all the major biochemical reactions in each higher life form, that knowledge could serve to permit each species, except man, to be its own bioassaying agency for us. Species other than man do not control the soil or environment. For these older species, from insects up through carnivores, the criterion of protein produced, including the required amino acids, aids in the assessment of soil fertility. Such assessments require increasing refinement as the biochemistry becomes more complex at higher levels of life. We need also to increase our knowledge of the biochemistry of plant nutrition, to extend our concepts of the soil’s functions to encompass more of the non-ionic reactions, including the chelated compounds containing both inorganic and organic ash percentages approaching those of living substances. And we need to accept a molecular biology. Modern man does not yet submit to the use of his body’s biochemistry as a bio-assay agency for measuring the soil’s productive capacity. Instead, he aims to modify the environment to his desires, many of which conflict with his healthy survival.

Man’s Synthetic Environments Reflect His Emphasis On Quantity, and Neglect of Quality

Man’s epoch, among the other biotic specimens, is but a minute segment of the paleontological column representing the earth’s populations of the many life forms as they have come and gone or remained.⁶ His art of agriculture is not more than ten thousand years old. Again, and most significantly, the systematic development of science and its product, technology, began only some three centuries ago, while the neotechnical revolution, bringing mass production and the injection of energy into our system through the internal combustion engine, has taken place within our lifetime. In Paul Sears’ words:

“Beginning with Darwin, biologists have shown the inseparability of life and its environment and the role of time in developing what has been, previous to man’s advent, a beautifully adjusted dynamic equilibrium…A few hundred years of technology have already disrupted biological and geological processes that were established over eons…The present effect of technology is at variance with the pattern of conservation of material and energy that prevailed in the absence of man…There is nothing in untouched nature to compare with our extravagant use of energy and our failure to recycle essential materials…Danger lies in the disruption of the great dynamic processes which have made the earth so generally habitable. Included here are the water cycle, soil formation, and energy storage by plant life.”⁷

Technology emphasizes quantity through mass production, high-speed chemical reactions, massive energy transfer to heat, and the shortened time required for output. The quality of the output depends on the particular parts and their order in assembling operation. Manufacturing industry has brought much satisfaction and economic success because its performance and products can be equated into values as monetary equivalents under sufficient control for perpetuation of productive capital, for matching production against consumption, and for guaranteeing profits. That satisfaction has generated the urban-based belief that agriculture, too, is only an industry, and should lend itself to corresponding increased output by means of increased power, higher speeds, and limited time according to the pattern of other industrial development.

That concept favors quantity output, but in agriculture it is slowly violating the quality of survival. Creation of living matter is not a process of assembling inert parts under human management. Rather, it is nature’s unique integration of biochemical processes at low levels of energy and over extended periods of time. For that, man is at best a benign cooperator with the natural laws of growth and evolution, at worst an observer and collector in disregard of them.

Our disregard of ecology is perhaps the major reason for disruptions of the biotic phases of agriculture by technological manipulation. Plants and animals, both domestic and wild, have been disseminated by man almost to the limits of their environmental tolerances without regard for the quality of the soil. In some situations man’s failure to manage the soil for more complete nutritional support of life forms has led to a decline in health. Environmental deficiencies, not readily recognized or remedied, have often been aggravated.

Selection of plant species and their propagation by mass production may sometimes result in metabolism modifications with increased output of carbohydrates and decrease of proteins. When the modified seed cannot be used for reproduction, the effects of the struggle for survival are eliminated. The plant’s conversion of solar energy into carbohydrates is at an efficiency of about 30 per cent. But converted into protein, the efficiency of energy conversion drops closer to 3 per cent. Modern industrial and economic concepts, based on quantitative yardsticks, do not tolerate such low conversion efficiencies. Hence the turn to hybrid corn, for example, and the consequent increase in quantity at the expense of quality. The mean of 10.3 per cent crude protein in corn has dropped to a low of half that during the last three or four decades in the United States. Corn is thereby started on the way toward self-extinction, becoming completely dependent on man for its survival.⁸

Along with the emphasis on carbohydrates for quantity production of cereals, there has been a similar selection and propagation of farm animals for rapid gain in weight. Much of the natural struggle for survival is eliminated by early castration. Feed is mechanically and chemically manipulated for the purpose of tranquilizing and fattening the beasts in minimum time. In the process much of the quality needed for healthy survival is lost, and the life span is shortened to less than a year in cattle raised for “baby beef” and even less for “ton-litter” pigs. Innate resistance to disease seems to carry the animals in sufficient health during these brief periods to escape pre-slaughter death in spite of metabolic degeneration or microbial invasions.

Studies of diseases and their many symptoms, together with biochemical irregularities correlated with them, emphasize the absence of natural health. We have not yet sufficiently recognized the possibility that microbial invasions of crops and livestock may be due to the decreasing ability of domesticated plants and animals to maintain their molecular biology, through their own instinct-guided nutrition, at the high levels required for healthy coexistence with microbes.

The biological or ecological view for the maintenance and preservation of species has been replaced by a commercial attitude which advocates mass destruction of microbes. Forgotten is the biotic desirability of maintaining the natural self-protection by which plants and animals were so well adapted to their environment before domestication. Problems of degeneration, viewed only as pests and diseases, have been aggravated, with a parallel reduction in the quality of product for nutritional support of man in better health.

Another illustration of the disruption of a natural equilibrium is the increasing failure of choice legume crops. This is a concomitant of our emphasis on quantitative increase in nitrogen measured only through ash analysis and the acceptance of that monovalent element as the bona fide indicator of total protein. We have not taken cognizance of the simple, natural fact that an amino acid may contain two atoms of nitrogen: one of amino form and of regular digestive value, the other in the four-carbon-ring form. The latter is indigestible and excreted in that same structure; so the chemical tests falsify the truly protein quality by just 100 per cent.

Chemical tests, often promoted by the desire to sell fertilizers, are not the equal of biotic assays, yet they are the props for the large but nutritionally unbalanced yields of nonlegume plants fertilized with nitrogen which today’s farmer is producing. At the same time, the animal’s refusal to eat the grasses in the hummocks of pastures fertilized in spots by its own fecal and urinary droppings indicates the imbalance of the fertilizer used. This is an example of one of the many disruptions of the natural coexistence of plants and microbes in equilibrium when monovalent salts of high solubility and speedy chemical reactions are introduced into the soil, even by careful placement away from the planted seeds.

Our mass-production technology applied to agriculture has produced economic surpluses of carbohydrates in the form of cereals and of fats from livestock. Industrial uses of those two materials offer no economic relief, when alcohol from treatment of crude oil can displace natural fermentation of grains, and chemical detergents can substitute for soaps. But now that our tastes for fats as carriers of flavor have been easily satisfied to include energy needs, and we have recognized the cardiac implications of obesity, natural proteins and their related organic and inorganic substances are becoming recognized in household terms as requisites for health. The increasing preference for naturally fresh, but highly perishable, foods as opposed to those industrially synthesized and preserved for long shelf life has led us to speculate increasingly about the relationship between poor health, biochemical degeneration, and breakdown in molecular biology. It is compelling us to trace these back from ourselves to our livestock, to our crops, and finally to our deficient or mismanaged soil. Quality in foods and feeds is at last under critical scrutiny for protein production through healthy species grown on fertile soils.

When “the proof of the pudding is in the eating,” a naturally healthy survival is the proof of the quality in agricultural production. For the demonstration of that, biotic assays must supplement chemical tests. Quality in food and feed products for healthy existence, as the species itself reflects it, must prevail first for microbes and plants through the medium of the soil. Then it must prevail as interrelations among all the higher segments or trophic levels, if quality in production is to support man in good health as the top segment of that biotic arrangement

Nutrition by natural choice is coming under the searchlight of science. We are beginning to measure the delicate impulses from the animal’s taste buds, correlated with those of olfactory origin, for taste reactions are significant natural means of measuring quality by choice. Such choice, expressed in amounts consumed, may be the major means of putting quality of production under quantitative categorization by biotic means.

Animal discrimination in quality may be very delicately adjusted. A hog’s selection of corn showed increasing consumption of that grain when it was organically fertilized with sweet clover. Rabbits have refused the same plant species when nitrogen was applied in increasing amounts, and the sexual vigor of the males was destroyed within a week when they were compelled to subsist on such plants.

Cattle are equally capable connoisseurs, or chemists. For eight successive years a herd selected one haystack, of four used as winter feed, in which the smallest share of its hay had been grown on soil treated with calcium cyanamide and superphosphate. Much more delicate discrimination by cattle recently have been observed now that inorganic salts may be offered cattle to assay the completeness of the ration, along with spectrographic analyses of the forages for trace-element content. In testing the opposing effects of copper and molybdenum, choices as delicate as ten parts per million have been claimed for dairy cattle. It might be questioned whether the choice of the castrated male would be as delicately adjusted.

The natural behavior of living species in relation to agricultural production suggests hope for prevention of degeneration of our crops, our livestock, and ourselves.We must pattern soil management for production that is in conformity with ecological knowledge and that does not go counter to biotic laws as revealed in evolution and the survival of species. The fragmentation of our thinking and action under technological and economic stimuli must be counterbalanced by integration into the geoclimatic foundation outlining the natural ecology. The species which we manage must be directed in more complete conformity with the factors we can assess, first, in the natural state and then duplicate in domestication. Fuller knowledge of the natural forces operating in agriculture, and those humbly modified by us with minimal disruption of natural processes, will result in quality first, to which quantity will be a sequel. Quality is a result of judgment by reasoned experiences, and hence comes only with maturity. Eventually we may arrive at maturity in managing soil resources more efficiently for the support of the entire biotic pyramid of which man is the apex and a dependent on all that is below him.

 

References Cited:

1. 1. William A. Albrecht, “Soil Fertility and Biotic Geography,” The Geographical Review, Vol. 67 (1957), pp. 86-105.
   2. E. R. Graham, “Soil Development and Plant Nutrition: Nutrient Delivery to Plants by the Sand and Silt Separates,” Soil Science Society of America, Proceedings, Vol. 6 (1941), pp. 259-262.
   3. William A. Albrecht, “Plant Nutrition and the Hydrogen Ion: Relative Effectiveness of Coarsely Ground and Finely Pulverized Limestone,” Soil Science, Vol. 61. (1946), pp. 265-271.
   4. Editor’s Note: In discussion, G. B. Bodman, Emeritus Professor of Soil Physics at BerkeIey, emphasized the fact that the quantity of crop produced is in no small measure correlated with the physical properties of the soil. Deeper soils are correlated with larger yields, but, owing to their gentle relief, are only too frequently withdrawn from agricultural use and become sites for airfields and factory, housing, and highway development. He pointed out that the yield of dry matter of several important field crops has shown to be affected by the nature of the energy of release: soil water-content curves which serve as indicators of time of irrigation for a given soil. The postponement of irrigation until the lowest limit of water availability to the plant has been reached may seriously affect yield. The “water-release curve” of a given soil is a soil quality, therefore, that is related to crop yield in irrigation agriculture. Trace elements in soil are quantity attributes. Several trace elements are known to affect the physiology of the plants grown on them and also the nutritive value of the plants to, and hence the health of, animals that consume the fodder. An instance was cited of molybdenum toxicity in the San Joaquin Valley of California which was traced to the form of molybdenum in the soil.
   5. Studies of the amounts of nitrogen and carbon in soils, especially their ratios, have established these as quantitative expressions of climatic potential for quality in agricultural production. See M. F. Miller, “Studies in Soil Nitrogen and Organic Matter Maintenance,” Missouri Agricultural Experiment Station, Bulletin 409 (1947); Hans Jenny, “A Study on the Influence of Climate upon the Nitrogen and Organic Matter Contents of the Soil,” ibid., Bulletin 152 (1930). This is the first of several papers by Jenny on this subject.
   6. William A. Albrecht, “Wastebasket of the Earth: Man and His Habitat,” Bulletin of the Atomic Scientists, Vol. 17 (1961), pp. 335-340.
   7. Paul B. Sears, “The Perspective of Time: Man and His Habitat,” ibid., Vol. 17 (1961), pp. 322-326.
   8. Editor ‘s Note: V. V. Rendig, Professor of Soil Chemistry at Davis, called attention in discussion to the relative “stability” of plant composition. Many properties of individual cells are of genetic origin and are not readily changed. Experiments which he cited, in which environment varied widely, have shown that many plant properties remain relatively constant in spite of environmental variables. One example given was the well-known ability of certain aquatic species to accumulate potassium even though the nutrient medium is much higher in sodium. The ability of the plant to “defend” itself against its environment can be exceeded, however. If this were not true, “foliar diagnosis” as a means of evaluating differences in soil fertility would not be the useful tool that it is. The “luxury consumption” of an ion such as potassium was also mentioned as a case in point. These and other examples show that the concentration of a soil-derived nutrient in the tissue of a plant bears some relationship to the level of that nutrient in the soil. It was also pointed out that the different levels of nutrients in soils may be reflected in plants by virtue of their role in some physiological reaction in the plant. As shown by an example taken from his own work on sugar metabolism, plants are able to perform reactions which are not considered as part of normal metabolism. Abnormal nutrition could induce the plant to call upon these normally latent metabolic routes. A note of caution was interjected regarding the evaluation of any of these changes which may be induced by variations in soil fertility, in terms of crop quality. Whether any such change could be called an effect on “quality” will depend upon the kind of organism that consumes it. Thus Professor Rendig’s experience has not shown that the more vigorous plant grown under conditions of favorable nutrition can defend itself better against preying insects than a less thrifty plant. In fact, the contrary has been observed in some kinds of nutritional deficiencies. Dr. Agnes Fay Morgan’s experience with fox skins, one from a pantothenic acid-deficient animal and one from its normal litter mate illustrated this. The gray-furred deficient skin was destroyed by moths in storage, but the dark-furred normal skin remained intact.