The Corn-Hog Ratio

This benchmark ratio is now increasing, evidence of serious trouble on the farm


Any good encyclopedia will supply you with interesting facts about zea mays, or maize, or Indian corn, or, in the United States, Canada and Australia, simply corn. Here I will reveal some lore not usually found in these sources, together with basic information for the encyclopedia-less. The U.S. name corn comes from dropping the "Indian" from Indian corn, just as Saratoga Chips gave us (potato) chips, so we needed another word for what were previously potato chips, and called them French Fries after the French habit of deep-fat frying superseded the American method of lots of lard and a frying pan. Corn has recently replaced wheat and rice as the world's largest agricultural crop. The U.S. harvests twice as much as China, and China much more than anyone else. In the 1940's, the U.S. crop was about 2.5 billion bushels. It was close to 9.3 billion when this article was first composed in 1999. In 2005, it was 280 million metric tons, or about 12 billion bushels (1 bu = 24 kg, approximately). Since about the same amount of land is planted, this nearly fourfold increase has been mainly due to the petroleum industry, which makes the herbicides and fertilizers that make this productivity possible, in addition to the fuel for the tractors, cultivators, harvesters, and husker-shredders. The thing that hasn't gone up is the price of a bushel of corn. Around 1980 it briefly exceeded $3.00, but remained in the mid-$2 range, where it has been since World War II, until the ethanol boom has increased it to $3.60, the most ever. The increased productivity has, however, meant a fourfold increase in return per acre. After reading this article, reflect on exactly how this fourfold increase came about, and what it means in the long run.

A bushel of No. 2 corn has to weigh at least 53 lb, have no more than 15.5% moisture, and satisfy a few other limits for broken kernels and such defects. For many years, on the Chicago markets, the price of 11-1/2 bushels of No. 2 corn had roughly equaled the price of 100 pounds of heavy hogs, and this was regarded as a kind of norm, the normal corn-hog ratio of the title. In fact, this ratio was 8.7 in 1940, 11.8 in 1950, 15.3 in 1960, 17.1 in 1970, 12.2 in 1980, 23.6 in 1990, and 20.3 in 1997. While the price of corn has been steady, the price of hogs has gone from $5.39 in 1940 to $52.90 in 1997. Pork production has not quite doubled since 1940, incidentally, so the petroleum industry has not made it possible to increase productivity very much. The pork grower has had the advantage of a fixed price for his most important ingredient. One might reflect on why the price of corn is not closer to a fairer $5.00 a bushel than half that amount. In 1783, when a laborer received $8-$9 a month, wheat sold for $3.00 a bushel, and hogs for $8-$10 a hundredweight. These were good prices, at a time of demand. My source does not give the price of corn, but corn was certainly the primary food of the hogs. If corn were half the price of wheat, the corn-hog ratio would be about 6.

The connection between corn and hogs is not coincidental. Hogs love corn, and it is their major food. One of the old ways of harvesting corn was to hog it, that is to let hogs in a field of ripe corn to help themselves. The hogs did all the work, and loved it. The city person thinks of corn as sweet corn, the delicious vegetable that comes in ears and cans. This is actually a garden or horticultural product, specially bred and harvested while immature, in the soft milk stage, when it can be eaten after minimal cooking. This corn does not turn all its sugar into starch, and so it tastes good to us. It is bred, in fact, to delay the production of starch, to maintain sweetness. When ripe, the kernels wrinkle up and harden. This corn gives a very poor starch yield, and so would be very inefficient for most of the uses of corn.

Corn is a domesticated grass, used immemorially by the original inhabitants of the Americas as a staple grain, which depends wholly on humans for its propagation. Corn must be cultivated; it never grows wild. They say it was developed in Western Mexico before 5000 BC by selective breeding of a wild grass, teosinte, with large seeds. Corn with a cob took thousands of years to develop. Modern corn is a result of genetic modification of the Indian corn, to enhance uniformity, starch production and disease resistance. It has a thick stalk, with the male flowers forming the tassel on top. The female flowers grow on the stalk, containing rows of ovaries on a cob for support, surrounded by modified leaves as the husks. Each ovary sends out a strand of silk, which extends out of the ear to catch the pollen from the tassel. The ovaries grow into the kernels, which consist of a tough coat or hull, the germ that grows into a new plant, and the endosperm consisting of starch in the ripe seed. As the corn ripens, the sugar supplied by the sap forms starch, and the moisture content decreases. The silk, having done its job, turns brown, and this is a sign that an ear contains full kernels without husking it to find out.

In dent corn the soft starch under the crown of the kernel shrinks more than the hard starch around the sides, so a depression forms in the crown of a ripe kernel. In flint corn the hull is strong enough to resist this. Popcorn is a special kind of flint corn. When the starch contains just the right amount of moisture, and the kernel is strongly heated, the steam pressure will rupture the hull and the endosperm will expand into the familiar white food delicious with butter and salt. Most corn that is raised is dent corn. Corn is raised for animal feed, industry, and silage. Most meat is produced where there is corn, not out where the buffalo roam. Sweet corn is a natural mutant in which conversion to starch is retarded, so if it is picked early and immature, it is pleasant to eat. The common corn of commerce is called field corn.

Many other crops are grasses, related to maize, but which do not produce ears. Sorghum is one example; it can be used for fodder, and the juice pressed from its stalks is sweet, producing a syrup like molasses that is an acquired taste (but one worth acquiring if you like sweet things). A kind of sorghum low in sugar is broomcorn, raised in Oklahoma for the straws supporting its flowers, which are bound together to make brooms. Other low-sugar sorghums, such as milo, are grown for the seeds, which have been used as a staple food in some countries. Sorghums grow well where other crops may not, because of lack of moisture or infertile soil. Sugar cane is a grass high in sugar, but it grows only in semitropical areas. Bamboo, the material of a thousand uses, is also a grass.

Modern corn is white or yellow. Yellow corn contains xanthophyll, a substance like carotene that gives vitamin A. White corn lacks xanthophyll, and is nutritionally not as complete. When white corn is used as feed, it should be supplemented with food like hay, which contains carotene. If you plant corn close together, it will not produce many ears, but will make lots of greenery. This moist greenery is cut, chopped, and fed into a silo where it ferments into something cows think is delicious, and which is also very nutritious, called silage. The idea of silage is for anaerobic fermentation to make lactic acid. When the pH gets to around 4, fungus, mold, and other nasty things stay away. It is a way of preserving fodder for the winter that is better than drying. Corn has enough starch to ferment very quickly and make good silage. If you make silage with alfalfa, you have to add molasses to provide something to ferment. One way to make silage is in a tall cylinder. The idea is that only the very top layer is exposed to the air, so the consequent respiration only produces heat here. Wet green stuff in a pile gets quite hot, and this heat must be disposed of. Many things that you harvest on a farm and make piles of have this property, that if they are too wet they will heat up and can catch fire.

Common corn cannot be eaten like sweet corn, since the hull is too tough. The favorite Indian process was to soak the corn in wood ash lye until the hull softened and expanded, producing hominy. When boiled, this can be very palatable, and was a very familiar dish. Alternatively, the kernels were pounded until reduced to a powder. This powder could be moistened and shaped into patties that could then be roasted or fried. The present-day tortilla is descended from this practice. The most popular tortillas are made from white corn, which does not supply vitamin A. Like hogs, people need a supplement when consuming mainly white corn. The Mexican government has a plan afoot to enrich tortillas so that they are a more complete food, an excellent idea.

Corn raised for grain can be fed directly to animals, or can be sent to the factory. In the factory, the germ produces corn oil, the coat bran, and the endosperm starch. The starch can be converted to oligosaccahrides by the enzyme alpha amylase, and the oligosaccharides into the monosaccahride, glucose, with glucoamylase. This glucose syrup is an excellent substrate for fermentation, producing ethanol and carbon dioxide. It was discovered around 1957 that the enzyme glucose isomerase could convert much of the glucose to the much sweeter fructose. The 42% fructose produced in this way can be concentrated by liquid chromotography to 90% fructose. The result is high fructose corn syrup 90, HFCS90. This can be diluted with glucose syrup to make HFCS55, 55% fructose, which is roughly as sweet as sucrose, cane sugar. HFCS42 is also produced. These sweeteners were introduced in 1975-1985, and corn is now one of the leading sources of sweeteners, because of the artifically high cost of sugar in the US. The endosperm can be rolled out and toasted to make cornflakes, or ground into corn meal. Since hog production has not quite doubled, while corn production has quadrupled, these other uses must have increased. Hydrolyzed corn starch can also be fermented to grain alcohol, ethanol, which has many uses. One typically American use was as whiskey, which every farm made before the temperance craze. Any corn the hogs didn't eat was put to this purpose. Taos lightning was a famous but unusual example of this. When Jimmy cracked corn he was taking the cork out of the jug. The fermented mash (water, starch and yeast) contained alcohol, which was recovered in purer form by distillation. If you let the still cook too long, you brought over fusel oil (higher alcohols) and poisoned your customers. In Iowa, 10% ethanol is put into gasoline and is sold rather cheaply. This works quite well, but is supported by a subsidy. No alternative is cheaper than gasoline from petroleum at the present time. That will change. A bushel of corn yields about 2.8 gallons of ethanol. E85 ethanol fuel, containing 85% anhydrous ethanol and 15% gasoline, has about 70% the energy content of an equal volume of gasoline. Hydrous ethanol, the 93% azeotrope resulting from distillation, has a considerably smaller energy content.

The traditional method of corn growing is no longer practiced to any extent. It was usual to plant several seeds in a hill, with the hills spaced 42 inches apart. Corn must be kept free of weeds, since it cannot successfully compete with them. At one time, cultivation (shallow digging) was the means used, but now it is chemicals. Corn requires a large amount of water, which in arid regions demands irrigation. When the corn was ripe, the ears containing about 40% moisture, the corn stalks were cut at the base, gathered, and shocked into conical corn shocks. The ears were allowed to dry further , and when down to 25% moisture the ears could be picked, husked, and cribbed, that is, put into open structures that allowed them to dry further. This was all hand work. Shelled corn is kernels cut from the ears and packed in baskets or sacks. Corncobs were found useful as tobacco pipes, and a special variety came to be grown for the extra large cobs that were suited to this application. If corn is grown year upon year in the same field, yields decrease. This can be avoided by crop rotation. The traditional three-year rotation was corn-oats-clover. Oats were necessary when the corn did not ripen soon enough to permit sowing of wheat, and clover replenished the nitrogen. Corn can also be rotated with soybeans with the same effect. The petroleum industry offers an alternative to crop rotation, tripling the output of an acre by applying chemical fertilizers. The yield per acre varies greatly, depending on the soil and climate, but 200 bu per acre is a reasonable average.

In the 1930's, hybrid corn revolutionized corn culture. It was always desirable to breed and select corn for the most desirable properties, such as pest resistance, or early ripening, and this was not difficult, because the male and female flowers were quite separate. Many corn varieties were developed early in the history of American agriculture. Hybrid corn, however, is something special. It was found that pure lines could be bred with desired characteristics, and the purity of the lines would guarantee consistency in the results. Always before, this process gave greatly reduced yields, so that pure heredity and high yield seemed mutually exclusive. It was found that if two pure lines were crossed, the cross retained the desirable characteristics while exhibiting high yields, a result of what was called hybrid vigor. If these single crosses were themselves crossed, the result was even more productive. Therefore, much American corn had four grandparents. The offspring of a cross has greatly reduced yields, so the hybrids have to be created anew in each generation. They, of course, do not breed true.

Corn was introduced to the rest of the world in the 16th century, and became a staple, especially in Africa, because of its efficiency in producing food and its palatability. Unfortunately, the result was often devastating attacks of pellagra and amino acid deficiency. The natives of the Western Hemisphere had avoided these plagues by their use of treatment with alkalis (wood ashes or lime), which activated the vitamin B, and by the concurrent consumption of beans and squash, which supplied the amino acids lacking in corn. Of course, the animals fed exclusively on corn suffered in the same way.

A more recent development was the introduction of genes that would cause an increased production of certain nutrients that previous corn strains had lacked, such as the amino acid lysine. Such corn was a much more complete food, and hogs thrived on it. The present furor over genetically-engineered foods neglects the fact that genetic engineering has been around for a long time, and is practically essential to the modern rate of production of food, especially hogs. Using what would be considered normal, organic methods in food production would mean that a large part of the current world population would quickly starve. The same thing will happen anyway when petroleum gives out (i.e. becomes expensive, which is the same thing, effectively).

Corn is a wonderful thing, and its study leads one into many paths, and engenders much reflection. It is said that when Iowa was searching for a state motto for license plates some years ago, "Corn, Hogs and People" was suggested. This summarizes the food chain very neatly, as well as the contents of the state.

Post Scripts

A letter in the Sunday Denver Post for 12 September 1999 displayed the prices for farm products quoted by the Colorado Agricultural Statistics Service as of 15 July. Wheat was $2.00 per bushel, and corn $1.66. Americans, by the way, don't eat these products -- their animals do. Hogs were $31.20 per cwt, so the corn-hog ratio was about 19, which is in line with recent trends. Beef was at $62.50, not a bad price at all. The writer bemoans that farmers can't afford to buy hay or grain to feed their animals. Well, grain could hardly be cheaper! Then he says we are sending free grain overseas, but neglects that this grain must first be bought from farmers, and if it were distributed free in this country it would damage the grain market even more. The lack of understanding of the problem is deep and endemic among farmers, who are actually capitalists out for their own success at the expense of others, and cannot cooperate even enough to stabilize their markets. In the West, many take advantage of heavily subsidized irrigation (leaving barren, salted fields and sediment-filled reservoirs) and overgraze marginal publicly-owned pasture (leaving cholla and sagebrush behind), essentially living off government largesse.

Added 3 Oct 2000: in today's paper, hogs were about $40 at Sioux City, and #2 white corn about $1.65 in Kansas City, so the ratio is about 24, because hog prices are slightly higher. These depressed prices give continued evidence of difficulties on the farm. They are perhaps actually lower than in 1940. Why does anyone stay in the business?

Added 24 March 2001: Economists teach that higher prices stimulate production, while lower prices depress it--the "law of supply and demand." But experience teaches otherwise. The collapse of oil prices in the 1930's brought on a glut, for example, when oil went for 10 cents a barrel. In today's paper, a report of the plight of potato farmers (Denver Post, p. 26A, from the New York Times) brings out the same thing. From 8 cents a pound, the price of potatoes has sunk to 1 cent a pound, well below the cost of production, 5 cents per pound. When the price was dropping, farmers planted more to keep up their income, only worsening the situation. I note that I pay 79 cents a pound in the supermarket for the same inferior-quality Idaho potatoes. The relation between supply and demand is more complex than the pronouncements of a pseudo-science imply.

Added 3 March 2005: Today the paper quoted $2.10 for #2 corn, and $75.30 for hogs, so the ratio is a high 36.

Added 6 April 2007: Corn is now in demand for making ethanol fuel, which has about doubled the price per bushel, so the farmer is very happy. There is also a $0.51 per gallon subsidy, which has caused ethanol factories to spring up everywhere. Ethanol yields about 327 kg-cal per formula weight of 46 g, while octane (typical of gasoline) yields 1303 kg-cal per formula weight of 114 g. In terms of carbon, it is remarkable that either fuel gives about 13.6 kg-cal per g of carbon. 1 g of carbon makes 3.67 g of carbon dioxide. When alcohol is produced by fermentation, an equal amount of carbon is released as winds up in the alcohol. Therefore, the apparent carbon load of ethanol is about twice that of gasoline. When the fact that photosynthesis got most of the carbon from the air is considered, ethanol is carbon-neutral, except for carbon released in its distillation. Alcohol made by hydrating ethylene releases no extra carbon, and is still the cheapest way to get alcohol. One seemingly reliable estimate says that bio-ethanol returns 1.34 units of energy for each 1.0 unit expended, not a very good ratio.


Return to Economics Index

Composed by J. B. Calvert
Created August 1999
Last revised 19 May 2007