FOOD SUPPLY OF THE WORLD. The population of the world is believed to be about 1,800,000,000. The land area (excluding the Arctic regions) is roughly 33,000,000,000ac., less than half of which is now regarded as arable. Taking good and bad land together, it may be estimated that five acres are re quired, directly and indirectly, to sustain one human being. Other things being equal, this would fix the limit of population of the globe at something like 6,000,000,000. The direct requirement of acreage per head of population will be reduced by improvements in agriculture and diminution in the number of domesticated ani mals. Nevertheless, one may regard a population of 6,000,000,000 as the point of saturation for the globe. But from this it is not to be inferred that such a population will ever be reached.
Historically considered, the proponents of the hypothesis of diminishing returns have over-emphasized the proposition, while underestimating the developments in agricultural practice. Up to the present, the agriculture of the world seems to have exhibited secular increasing returns. Statistical data are not complete enough to justify categorical statements, but the evidence lends support to the view that, considered by and large, the agriculture of the world has shown increasing rather than diminishing secular returns. How far this may continue is another question; but the non-ful filment of inferences drawn from Ricardo and Malthus have trans ferred the problem from the domain of speculation to demonstra tion. Patton has remarked that : "Secular diminishing returns can be said to occur if the number of hours required to produce a given quantity of food-stuffs shows a tendency to increase, or if a growing proportion of the world's labour supply is necessary to produce enough food to avert starvation." Such secular diminish ing return has not been statistically demonstrated, and until this ultimate result has arrived, the import of the abstract notion is not clear.
In two directions in particular, improvements still to be accom plished will result in wide extension of agricultural operations throughout the world. Predatory animals, insects and parasitic diseases have inflicted enormous losses, so onerous indeed as to operate heavily in restraint of agriculture, both intensively and extensively. Some of the enemies of the agriculturist tend to retreat with advancing population ; but others, in particular certain diseases of plants, are favoured by increasing concentration of cul tivated units. The problem is both direct and indirect : direct as involving the plants and animals that represent the crops of agri culture, indirect as involving human beings, for whose occupancy, disease-infested regions must be made safe. It seems now estab lished that if infectious diseases are eliminated, all parts of the tropics are fitted for habitation and agriculture. The effects of tropical isolation have apparently been much exaggerated. If the world could be made free of infectious diseases involving human beings (in particular those transmitted by insects, among them sleeping sickness, yellow fever, typhus and malaria), the world scope of agriculture would be greatly extended. If, thereafter, predatory animals, insects and infectious diseases destructive to domesticated animals, forests, orchards and plants could be re duced to a minimum, or exterminated, the result would be an enormous increase of output with lowering of cost. Notable ad vances have been achieved in the prevention and control of infectious diseases of animals. Less has been achieved in the prevention and control of infectious diseases of plants; and it is not too much to say that herein lies one of the major future prob lems of agriculture. These improvements are entirely practicable, technically and socially. If one will compare the sanitation of civilized communities with the sanitation of backward countries, and apply a corresponding advance to the control of predatory animals, insects and infectious diseases afflicting animals and plants, one secures a measure of the possibility of future improve ments.
The potential of the agricultural resources of the world cannot be regarded as even relatively attainable until full application is made of the principle of the division of labour. This implies fluidity of transport, both within countries and between countries, also fluidity of credit and convertibility of exchanges. Quaran tines must cease to set up barriers to international trade. These several conditions are not yet attained for any one continent, and their attainment for the world at large will presumably be delayed beyond the lifetime of the present generation. Fertilizers represent a substantial, if indirect, agricultural resource, since the indispens able elements must be returned to the soil if depletion is to be controlled. Valuable as are the natural manures, they fall short of the minimum requirements. Recent improvements in manufac turing technique have greatly enlarged the supply of chemical fertilizers. With cheapening of fixation of atmospheric nitrogen, improvements in recovery of low-grade natural saltpetre, and con tinuing development of recovery of ammoniacal by-products, the supply of nitrogenous fertilizers may be expected to expand greatly and the price to decline. The available and developed deposits of phosphate rock promise also relatively unlimited sup plies of soluble phosphate, presumably on a declining price level. The same thing may be said of potash, of which the out-turn from developed deposits in different parts of the world is being re strained in order to maintain price. In addition, fixation of atmos pheric nitrogen through the action of micro-organisms in the soil is becoming better understood and more effectively applied. Cor responding actions by micro-organisms, whereby insoluble phos phate and potash are converted into soluble forms in the soil, seem also to exist, and in view of what has been accomplished with nitrogen it does not seem utopian to look forward to practical developments in these directions. In the gradual transfer of agri culture from the extensive to the intensive basis, the use of ferti lizers may be expected to become continuously more important.
Soil erosion is an important and difficult problem in many parts of the world. It has different causes in different regions, such as slashing of forests, destruction of brush cover, over-grazing, arti ficial drainage and misdirected tillage. Soil erosion tends to be progressive and the area denuded is added to annually. Loss of surface soil, loss of water and alteration of terrain are all of importance. Soil erosion, like reforestation, becomes a public problem because there is little incentive for private capital to enter upon long-time corrective measures.
It is an anomalous situation that the world is just now concerned with the economic problem of surplus of agricultural products and at the same time constrained to fear that the pressure of population on resources may soon lower the level of subsistence. In truth, however, the anomaly consists not in the questions themselves, technically considered, but in lack of perspective of the time rela tions. The present surplus problem, which in one way or another is practically world-wide, is not an emergency, but is still to be regarded as a relatively short-time situation. On the other hand, a forecast of significant pressure of food supply on population lies far in the future, even in the view of neo-Malthusians.
In judging of the agricultural potential of the globe, we must bear in mind that land has other uses than raising primary food stuffs and supporting domesticated animals. Land must also be used for producing trees and fibres—industrial raw materials. The world requirements of building timber, fuel wood, paper pulp, rubber, cotton, linen, jute, hemp, sisal, naval stores, gums and other raw materials, are large and for the most part expanding. Since the growth of forests is rarely at the rate of over 3% per annum, in terms of material, the current rate of depletion of forests would seem to imply that in the not distant future, land in many countries will need to be formally withdrawn from agri culture for reforestation under State control. There are many sub stitutes for wood for building, but while the relative demand may decline through substitution with other materials, the absolute requirements, with growth of population and improvement in standards, may exceed the prospective rate of growth of the estab lished stands of timber. The per caput use of rubber is steadily expanding. The per caput use of fibres for clothing is apparently growing slowly, if at all, while its use, outside of clothing, is obviously expanding. One must expect the time to arrive in the near future when in many countries it will be more profitable to raise industrial raw materials over certain areas than to raise food crops, feed crops, or animals. One must not construe the expanding world requirements of industrial raw materials grown on land as an enlargement the Malthusian doctrine, whereby the future race may be compelled to choose between being warmed from the inside by food or warmed from the outside by clothing and dwell ings. But it is necessary to bear in mind that modern improve ments in the standard of living carry with them greatly enlarged consumption of industrial raw materials, at the same time that food requirements are being reduced through substitution of ma chine power for manual labour and better protection of human beings from the elements.
The second division of agriculture includes land and labour devoted to the raising of animals primarily for production of industrial materials. There are now few countries in the world where animals are raised solely for wool and hides. The sheep, goats and cattle kept primarily for hides and wool furnish more or less milk and meat; indeed, in many countries meat is a joint product equal in importance with hides and wool. The land de voted to raising animals for hides and wool is to a large extent, in the present state of agriculture, not adapted to the raising of primary food-stuffs.
The third division of agriculture includes land and labour devoted to the raising of industrial plant products. Much of the land thus used in the temperate zone is adaptable to the other forms of agriculture, but in the tropics, this is less the case.
The fourth division of agriculture includes land and labour devoted to the raising of animals primarily for the production of milk and meat. Cattle may be used incidentally as work animals, and hides and wool are important joint products; but the primary purpose of such animal husbandry lies in the out-turn of secondary food-stuffs. In agriculture, the land devoted to such animal hus bandry is usually adapted to the raising of primary food-stuffs, and is devoted to animal husbandry as the expression of economic or vocational choice.
The last division of agriculture includes the land and labour devoted to the raising of primary food-stuffs—tillage for harvested crops. Such land is also necessarily employed in the raising of feeding stuffs for domesticated animals.
These five divisions of agriculture overlap to some extent in all countries, varying according to the place and time. With im provements in transport and exchange, and with increase of popu lation, these relations tend to change in the direction of increase in the agriculture devoted to primary food-stuffs with decrease in the agriculture devoted to animals and secondary food-stuffs. The conversion of nutrients into animal products is a wasteful process on account of the metabolic and caloric requirements of the ani mals. With continued increase in population, the food supply will tend to contain more of primary and less of secondary food-stuffs. If one can imagine a population of 5,000,000,000 on the globe, one must picture their diet as largely vegetarian with only such animal products (disregarding aquatic animals) as would be se cured incidentally from work animals and such cattle, sheep, goats and swine as could subsist on land unadapted to the growing of primary food-stuffs plus the residues of primary food-stuffs de voted to human beings. Such animal husbandry, for a population of S,000,000,000, might be as large as the present animal hus bandry of the world, or larger, particularly in the event of control of animal diseases in tropical regions. Obviously, however, the intake of secondary food-stuffs, animal products of all kinds, would be lower than to-day. There is enough truth in the doctrine of vegetarianism to make it clear that with proper selection and combination of different plant products, a competent diet could be arranged to include only such animal products as could be secured without using for animals land adapted to the raising of primary food-stuffs.
A convenient classification of food-stuffs, commercial rather than botanical, separates the main food-stuffs into five groups : cereals, legumes, roots, oil-seeds and animal products. The remain ing food-stuffs, mostly fruits and vegetables, though highly nutri tive, have little importance as sources of energy and only incidental significance in international trade. Different peoples, in different regions and circumstances, cover their protein requirements with various amounts of animal products, cereals and legumes, and their caloric requirements with different amounts of carbohydrates and fats. The standard of subsistence is at once a cause and a result of agriculture and commerce.
An estimate of the cereal crops of the world is to be undertaken only in very rough figures, since for large regions, especially Asia, reports are mere guesses. If in any year the grain fields of the world were to have large crops, the wheat would approximate 5,000,000,000bu., rye 2 ,000,000,000bu., corn 4,000,00o,000bu., oats 4,500,00o,000bu., barley 2,000,00o,000bu., and rice 4,000, 000,00o bushels. Converted into pounds, this would mean for the world population of r ,800,000,000 a per caput supply of about 600lb. per annum for all purposes. Grain used for seed and animal feed would represent a heavy proportion. Despite relatively small numbers of domesticated animals in Asia, contrasted with the human population, it is difficult to picture more than half of the grain produced in the world being consumed as food for human beings.
Wheat occupies the premier position, largely on account of gluten, which enables wheaten flour to be baked in loaves of yeast-leavened bread. Rye resembles wheat in this particular. Rice, maize, barley, oats and the sorghum grains do not lend them selves to the making of yeast-leavened bread. These grains are therefore used in the form of groat, grits, flakes or meals, pre pared for ingestion by steaming, boiling, baked as biscuit or used as alimentary paste. To some extent, the preparation of cereals depends upon the cost and the nature of available fuel; this is one of the elements in the preference accorded to rice in Asia. Al though wheat is raised in large amounts in both China and India, rice and millet are the predominating cereal.
While cereals may be consumed in their natural state, or crushed and milled without loss, it is customary to separate the cereal meals into a flour and offal fraction. The offal comprises the coat and the germ, including the bran; the flour corresponds roughly with the endosperm of the seed. In the case of rice, the offal is removed by polishing, without crushing the berry ; a similar process is followed in the manufacture of pearl barley. Broadly speaking, in the manufacture of cereals into food-stuffs, between one-fourth and one-third of their weight is thus separated as offal. This offal is employed as concentrated feeding stuff for domesti cated animals, for which it is highly prized. In regions where animal husbandry is undeveloped, cereals tend to be consumed in their entirety. Also, there is some consumption of whole-grain flour in all countries, since whole-grain bread is preferred by some to bread made of bolted flour. In fact, the offal of cereals con tains elements of value in nutrition—mineral salts, vitamines and roughage. If one were subsisting solely on cereals, it would be necessary to consume them in their entirety. In a mixed diet it is a matter of choice. Bolted flour and whole-grain flour are both incomplete foods ; in a diversified diet, however, the one is as good as the other, since it is possible to secure in fruits and vegetables the minerals, vitamines and roughage removed from grains in the manufacture of bolted flour. In countries with a diversified diet, the milk-equivalent of grain offal is more important than the offal as human food.
The cereal-raising capacity of the world is by no means fully developed. A world crop of 6,000,000,000bu. of wheat is possible within a relatively short time. Beyond the wheat lands lie the rye lands, rye being a hardier cereal than wheat, and representing the second line of bread defence. It would not be extravagant to suggest a world crop of 3,000,00o,000bu. of rye, along with 6,000, 000,000bu. of wheat. Corresponding expansions are also feasible for the other cereals. All in all, therefore, it would not seem out of perspective to envisage the gradual expansion of the world crop of cereals during the next century, to double the present volume if necessary. Since the per caput count of domesticated animals is expected to decline, a continuously larger proportion of cereals would be used as primary food-stuffs, and the expanded future population of the world would depend more upon cereals than at present.
As population increases, the production and consumption of legumes may be expected to expand, primarily in substitution of meat, and later possibly in substitution of grain. For North America, western Europe and the dominions of the British empire outside of India, this development lies in the distant future. For them, these legumes remain merely vegetables, in the United States, indeed, of declining use and not a staple source of protein in the national diet.
Though coming from a stalk and not from a root, cane sugar is to be classed with beet sugar. Before the World War, the world production of sugar was about i 8,000,000 tons, of which about half was cane sugar and half beet sugar. The present sugar pro duction is around 25,000,000 long tons, of which i 6,000,000 are cane sugar and 9,000,000 tons are beet sugar. As a result of the World War, the production of cane sugar expanded, that of beet sugar contracted. With the recovery of beet sugar, the level of world sugar is rising. Broadly speaking, beet sugar is a product of the temperate zone, while cane sugar is a product of the tropical (or sub-tropical) zone. With selection of seed, protection from pests and diseases, and appropriate fertilization, the output of cane sugar on tropical lands seems to be a function of tempera ture. Much land adapted to sugar-cane is still available for future expansion of that crop and substantial increases in the yield per acre is demonstrably practicable. In the case of the sugar-beet, with selection of seed, control of diseases and pests, and appropriate fertilization, the output seems to be the func tion of hours of sunlight ; and, other things being equal, the far ther north the beet can be brought to maturity, the higher the sugar content. Large areas still remain adapted to the sugar-beet, so that substantial future expansion is practicable. The refining of sugar is an efficient and economical operation, producing a concentrated and non-perishable food-stuff of expanding impor tance in the diet and in international commerce. Both crops are restrained by hand-labour requirements, as yet unsolved by de velopment of machines. A world crop of 30,000,00o tons of sugar is to be anticipated within a decade or two.
The world crop of potatoes is not even roughly measurable. The usual crop in North America and Europe except Russia, is around z 00,000,000 long tons. Potatoes of one sort or another, white and sweet, are adapted to many climates and soils and give a large yield of calories per acre. Potatoes are of outstanding importance in Europe and North America. They have not secured the favour of oriental peoples, due presumably to the fact that the oriental diets are already low in protein. The potato is highly perishable, and does not lend itself to refining, as does the sugar-beet ; con siderable potato starch is prepared for food and industrial use, but nothing comparable with the refining of sugar. The potato remains, therefore, an important vegetable, of limited transport ability, but highly valuable as human food, animal feeding stuff and material for the fabrication of alcohol.
The tropical flora include a number of plants whose roots, stalks and leaves contain large deposits of starch. Of these, the cassava and the sago-palm are the best known. The cultivation of these plants is expanding and land adapted to them is abundantly avail able. They are of course one-sided food-stuffs and need to be supplemented with protein. But as sources of cheap starch, they are of considerable importance. These farinaceous products com pete with rice rather than with wheat and are broadly comparable with the potato in the diet. The production of these food-stuffs may be expected to expand upon improvements in machinery for harvesting and refining quite as much as upon adaptability of soil. Oil-seeds.—An important and expanding food resource has, within comparatively recent times, been uncovered in oil-seeds. Under this term are included all seeds and nuts that are rich in oil; the segregation of grains from oil-seeds is of course to some extent arbitrary. The important oil-seeds include flax, tung, olive, sunflower, rape, sesame, soya-bean, peanut, cotton, palm, palm kernel and coconut. Some of the plants are annuals or perennials, some are legumes; some come from grasses, others from trees; some are strictly tropical or subtropical, others widely distributed over the temperate zone.
Oil-seeds contain starch and protein as well as fat. Contrasted with grains, they contain much more fat and protein but much less starch. Since protein is relatively scarcer than fat and starch, oil seed crops would seem to possess some advantage over grain crops ; but for several reasons, both agricultural and nutritional, the theoretical advantages of an oil-seed crop frequently disappear in practice. The principal disadvantage of the oil-seed crop is that the unexpressed meal is unadapted to culinary uses, while the ex pressed meal is much less esteemed than flour. In the case of the soya-bean, the Chinese have developed uses whereby the expressed meal, freed of fat, finds uses comparable to those of meals from grains. But in Europe, the expansion of soya-bean growing is lim ited by disinclination of the public to expand the food use of the expressed residue. To use the meal as feeding stuff is an imperfect solution of the problem, because the recovery of the protein in terms of edible animal products will be not over one-third, and often less, of the protein of the oil-seeds. To raise an oil-seed primarily as a source of fat, with secondary utilization of the protein and starch as feeding stuffs, is much less advantageous than if two or all three could be employed as food-stuffs. Up to the present, the fat-free residues of coconut, palm, palm kernel, peanut, sunflower and flax are used largely as feeding stuffs, and for little else. Nevertheless, oil-seeds have a large importance as a food resource, and as a concentrated feeding stuff, the residues are highly important in the industrialized countries of Europe and North America.
Apparently, the production of oil-seeds could be greatly ex panded if agricultural hindrances in the tropics could be over come and the utilization of the fat and carbohydrate as food-stuff brought into conformity with established customs and tastes. In a certain sense, it was tropical oil-seeds that made possible the present industrialization of Europe. To what extent added expan sion in tropical oil-seeds will contribute to the further develop ment of industrialism in Europe, indirectly by providing feeding stuffs for European animals or directly by providing food-stuffs, is a matter on which it is hardly possible or desirable to speculate. When one attempts to forecast the future use of oils and fats in the diet, it is necessary to realize that to a considerable extent vegetal oils and fats are competitive with animal oils and fats and that consumption may shift from one to the other. The tropical regions possess surpluses of vegetal oils; nevertheless, animal fats (butter, milk, lard and pork) are shipped in to meet the desires of the white population. On the other hand, the in dustrial nations of the northern temperate zone are increasing the use of vegetal oils from the tropics. It is not possible to say whether the use of vegetal oils and fats in Europe and North America is merely additive, supplementing animal oils and fats; or whether, and if so to what extent, it represents a substitution. In any event, it is clear that for some countries the point must have been reached where the current use of vegetal oils is in partial replacement of animal oils and fats. Certainly also, it is difficult to doubt that in the future the trend toward substitution is likely to become more pronounced. It is hard to interpret other wise the enormous expansion in the manufacture of vegetal lard substitutes in the United States and vegetal butter substitutes in Europe. When the imitations are made technically perfect, use will be based on price. Vegetal lard substitutes have made little headway in Europe and vegetal butter substitutes have made little headway in the United States. We do not expect the use of butter substitutes to expand rapidly in the United States, but it is to be anticipated that the use of vegetal lard substitutes will expand largely in Europe. Gradually it will become true for the food supply, as it already is for the manufacture of soap, that one fat is practically as good as another.
More important than the number of domesticated animals is the improvement in grades. With each generation measurable progress is achieved in all except backward countries. Through breeding and selection, improved types are secured ; animals are brought to maturity earlier, by better utilization of nutrients, and the turn-over is increased. In the case of sheep, improvement is attained both in wool and in the carcass. In the case of cattle, the frame and flesh are being improved, but the improved breeds do not possess the heavy hides of unimproved breeds. With each decade, the average annual secretion of milk rises, and the return of milk per unit of nutrient is enlarged. The same fact holds for swine ; both the lard-type and bacon-type hogs are brought to maturity earlier and the return of nutrients in the form of edible products is enlarged. In the case of all animals, a considerable part of the gains have been the result of cutting down the mortality in early life, thus increasing the turn-over of the breeding stock. In short, while the number of animals per million inhabitants may he declining, the out-put of edible products per head of popula tion may be increasing. However, we have no trustworthy statistics.
The meat consumption of the world is very unevenly distributed, the highest being observed in Australasia, Argentina, Canada and the United States, the lowest, in Asia. Consumption of meat is influenced not merely by the state of agriculture, relation of popu lation to area and limitation of transport, but also by fanaticism and superstition, as is illustrated in the dietaries of Hindus, Mohammedans and Jews. Occasionally one observes a country, such as Japan, in which consumption of fish takes the place of consumption of butcher meats; but for the most part, fish cannot be relied upon to replace the flesh of domesticated animals.
It seems reasonable to conclude that the consumption of milk may everywhere be expected to increase. Fanaticism and super stition do not oppose the use of milk. With improvement in the herds in pastoral countries, incidental milk production tends to increase. The decline of animal husbandry on public ranges, with increase in diversified agriculture, represents enlargement in the production of milk. Finally, improvements in the manufacture of butter, butter oil, cheese, condensed milk and dried milk are gradually making practicable the utilization of the milk of animals in outlying regions. The importance of this trend of developments is enhanced by the fact that the milch cow is an efficient con verter of feeding stuff into food-stuff.
To some extent marine animals find uses outside of the diet. Substantial amounts are employed as fertilizer and animal feed. The oils and fats find widespread uses in industry. For some marine animals, extermination is to be feared because of their ex ploitation for industrial materials.
The technique of catching fish and other marine animals has been highly perfected within recent years, and distribution and utilization have been advanced by technical developments. Fish do not need to be salted, but may be transported frozen over long distances. Extensive processing and packing may occur on the high seas. Marine fats may now be so refined and transformed as to become substitutable for vegetal and animal oils and fats. Thus, from marine fats may be prepared butter substitutes that are nearly as good imitations as margarines prepared from vegetal oils. Up to the present, the public is unsympathetic to such sub stitutions; but experience teaches that this attitude will wear off with time. The future questions are not the extent to which marine materials may be adapted to food uses, nor the conversion of the public to such use, but rather the quantity of material available and the prospective length of time over which new industries might count on supplies large enough to make it worth while to develop the business.
The present use of the flesh of fish and other marine animals in the human diet cannot be measured. For North America, the fish of salt and fresh waters are little more than incidental luxuries; but in the countries of western Europe, in regions surrounding certain inland seas, like the Caspian, and in the coastal regions of Asia, fish constitute an important part of the diet. The trend of output is impossible to estimate. Over-catching is difficult of restraint, both in inland and territorial waters, and especially on the high seas. Gradually we are coming to question the practical results of artificial propagation in hatcheries. Pollution, whether by oil film on the surface, suspension of insoluble particles, or solution of noxious chemicals, has everywhere widespread and de structive effects, especially to the young. Apparently, fresh and coastal water fish are on the decline, also fish that come from deep-sea water to spawn in fresh water or vice versa. The whale, walrus, seal and other large marine animals are, only incidentally, sources of food supply. With respect to other marine animals, the evidence is less conclusive. Fishing on the high seas is at pres ent largely confined to banks, most of which are adjacent to the mainland, of which the banks off western Europe and Newfound land may serve as illustrations. It is difficult to measure the trend of fish supply on such banks. With replacement of sails with motors, the efficiency of fishing and radius of cruising are much increased. There is the feeling in trade circles that the sup plies of cod, herring, halibut and mackerel are on the decline. Be yond this, there is a popular notion that practically unlimited num bers of fish exist in deeper and more distant waters (especially tropical waters) awaiting improvement in methods of fishing, with the technique of refrigeration already perfected. Just how exten sive are such supplies of fish, what are the limitations of season and the costs of procurement are not known. One cannot, how ever, resist the inference that the importance of deep-sea fish, like that of the reindeer, is more hypothetical than demonstrated.
In a mixed diet the flesh of fish, on the basis of dry weight, has about the same value as the flesh of domesticated animals. The fats of fish differ rather widely from those of domesticated ani mals, but by modern technological methods lend themselves both to industrial and dietary uses. Refrigeration and canning make the flesh of fish as safe and dependable as that of domesticated ani mals. It is, however, doubtful if the flesh of fish will ever exert a world-wide appeal as a food of preference. The use of fish on fast-days has not tended to favour its use as a regular article of diet. On the whole, the flesh of aquatic animals contributes rela tively little to the food supply of the world in terms of calories and for the immediate future the prospect is for decline rather than for increase.