Vetter: shortage of new graduates The second factor, high school graduation rates, he calls a real enigma. Contrary to his earlier projection of a 1%-per-year gain from 78% in 1970 to 90% in the 1980's, the graduation rate has dropped 3% in the past three years. Dr. Cartter now projects 18% fewer high school graduates in 1990 than he had before, and feels that the rate may not hit 85% until the end of the century. The main reason for the change seems to have been the ending of the military draft. The draft change also has cut the percentage of high school graduates entering college from 60% in 1970 to 55.5% in 1973, Dr. Cartter notes. This leads him to forecast just an 18% increase in total college enrollments in the 1970's, far below projections of 40% and up from other sources. Converting this projection to a student-faculty ratio yielding faculty demand, Dr. Cartter sees a two-thirds cut in new college teacher hiring to 10,000 per year in the later 1970's. The rate will drop further to 6000 per year in the 1980's, and then settle to a replacement rate of 10,000 per year in the 1990's. One final factor, the percentage of Ph.D.'s among college teachers, has been dropping lately. New Ph.D.'s have compensated for a declining outlet in university jobs by going in far greater numbers into nonselective fouryear colleges, two-year colleges, and secondary teaching. Summing up, Dr. Cartter says that the 1970's always looked like a time of modest, stable growth in college outlets for Ph.D.'s. He believes the real problem will begin in the 1980's and now thinks that it will last for the rest of the century. "I used to say that 1970 was a good year to have reached tenure. I now say 1970 was a good year to have retired." Any realization of Dr. Cartter's pro-
jections could aggravate the none-toocheerful prospects for women and other minorities in the science and engineering fields. Statistics professor Elizabeth L. Scott of the University of California, Berkeley, says that, even if the current discouraging outlook for women and minorities in these fields were improved by forced-draft hiring with quotas, it would take decades to make much improvement in the exceedingly low percentages of minorities on college faculties. Sharing some of the woes of minorities in engineering and the sciences are bachelor-degree holders. This littlestudied group is a truly invisible segment of the technical world and tends to disappear in large numbers into other fields, reports Dr. Lewis C. Solmon of the National Research Council following recent research carried out with Ann S. Bisconti at Management Resources, Washington, D.C. Dr. Solmon became interested in bachelor degree-holders because he suspected that a manpower demand created by the energy crisis might affect them, especially in jobs such as geology and production chemistry. He also felt that upgrading B.S.-level professionals in times of shortage might be an easier route to fill demands than starting a basic campaign in high schools. Dr. Solmon's initial results using raw data from the American Council on Education seem to confirm his suspicions. First, he finds large percentages of bachelor-degree holders quitting the field of their training. Secondly, he finds that the apparent reason why men are leaving is generally a push out rather than a pull toward other fields. For women, the opposite is often true, with the brightest graduates leaving their fields for better opportunity elsewhere. However, in chemistry, Dr. Solmon finds evidence that more ambitious male baccalaureates search for less limiting fields than the outlets traditionally open to them. Indeed, bachelor-holders remaining in chemistry are much less satisfied with their work and see fewer opportunities than do their fellows who go into fields other than teaching. Dr. Solmon's overall conclusion is that if jobs would open up, most bachelor-degree holders who entered other fields could be attracted back. He thus sees a large potential pool of unused technical manpower. Will such reserved manpower ever be realized? The prospect is no more wildeyed than some other recent developments that have upset forecasts. The AAAS speakers agreed that manpower supply-demand forecasts in technical fields have been almost universally wrong over the short term. With the recent cut in federal support for such forecasting, the unforeseen could again be the rule in this roller-coaster balance.
Agriculture depends heavily on energy One of the few constants in the political and economic crises of the past few years has been the productivity of U.S. agriculture. U.S. farms have been an ace in the hole not only for national concerns such as the balance of payments, but for worldwide worries such as overpopulation and famine. In an enveloping energy pinch, however, this constant may not be so constant after all. For U.S. agriculture is a high-energy business. How high and of what kind this agricultural energy input is and how efficiently it is used took the attention of a standing-room-only crowd at the annual meeting of the American Association for the Advancement of Science in San Francisco late last month. Among the more provocative thoughts presented were that modern agriculture leans most heavily on the scarcest energy form—natural gas; that huge increases in energy input on modern farms often have brought nowhere near the corresponding increase in output; and that a surplus in farm output has only encouraged even less efficient production of food through animal protein. For perspective, all speakers agreed that agriculture takes a fairly small percentage of U.S. energy. An estimate of this portion for 1972 is 3.5%, according to calculations by Dr. Gary H. Heichel, associate plant physiologist at the Connecticut Agricultural Experiment Station in New Haven. His breakdown of this agricultural total of 665 x 10 12 kcal. shows the largest fraction, 32%, going for tractor fuel. Next is fertilizer with 23%, then metals and machinery with 20%, electricity with 14%, pesticides and other chemicals with 6%, animal feeds with 2%, and other uses with 3%. By type of energy, natural gas seems to have a surprisingly large edge. At least this is the conclusion of a comprehensive survey completed this January in California by the state's department of agriculture. Presenting the findings, department analyst Vashek Cervinka said that natural gas supplied 53% of the state's agricultural energy needs through the processing stage in 1972. Other energy types were far behind: diesel fuel with 18%, electricity with 16%, gasoline with 11%, liquefied petroleum gas with 2%, and aviation fuel with less than 0.5%. Agriculture's energy input goes through a use chain of highly varied efficiency. What this human-supplied or "cultural" energy actually does is assist crops in harvesting solar energy, Dr. Heichel explains. "A small part of cultural energy is conserved when the crop uses plant nutrients from fertilizer, but most is ultimately dissipated into the environment as heat, not transformed into harvestable energy." The fuel energy supplied crops by March 11, 1974 C&EN
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sugar beets, peanuts, and U.S. rice, which consume about twice the cultur al energy of corn but yield about half Digestible energy yield. 103 megacalories per acre per year the digestible energy. Sugar beets yield • only twice the digestible energy of oats 30 12 but consume about four times the cul tural energy. North Carolina peanuts yield twice the digestible energy of •11 Missouri soybeans but at a cost of four 20 h • times the cultural energy. ΛΑ 5 In the California study, a similar 14 φ 8 ^# disparity in energy conversion efficien • • cy between grains and vegetables 10' *- · 1 0 • • J 10h shows up. The state's grains generally 3 6 · ^"/ 13 13' Λ yield several times more product ener •2 ·7 9 gy than the economic energy supplied, but most vegetables and fruits give an I I I ι I I energy conversion ratio of less than 2 4 6 8 12 10 14 one. Cultural energy, 103 megacalories per acre per year The energy conversion ratio becomes far worse with the additional food1 Rice, irrigated; Philippines, 1970 9 Soybeans; Missouri, 1970 making step involved for several im 2 Vegetable; New Guinea, 1962 10 Sugarcane, no processing; Hawaii, 1970 portant crops—feeding to animals to 3 Corn, grain; Iowa, 1915 10' Sugarcane, including processing; Hawaii, 1970 4 Corn, grain; Pennsylvania, 1915 11 Corn, grain; Illinois, 1969 increase protein yield for human use. 5 Corn, silage; Iowa, 1915 12 Corn, silage; Iowa, 1969 Dr. Heichel says, "We estimate that 6 Alfalfa, hay; Missouri, 1970 13 Sugar beets, no processing; California, 1970 the 40% of the food energy in our diets 7 Oats; Minnesota, 1970 13' Sugar beets, including processing; California, 1970 8 Sorghum, grain; Kansas, 1970 14 Peanuts; North Carolina, 1970 contributed by meat and other animal 15 Rice, irrigated; Louisiana, 1970 products like butter, fats, and oils con sumes over 80% of the feed energy an humans now rivals solar energy in U.S. crops in the early 1900's and in nually harvested for crops. . . . Broilers amount, Dr. Heichel says. But there's 1970. The crops with the least cultural and hogs return about 0.1 calorie in a big difference in how efficiently each energy gave low yields of digestible en meat per calorie of feed, but cattle re is used. "Modern agriculture uses cul ergy, about 5000 to 6000 megacalories turn only 0.04 calorie." tural energy 100- to 500-fold more effi per acre per year. However, this yield The detour of grain to animals on ciently than plants use sunlight, and represents a very high recovery of the way to human food is becoming 10- to 50-fold more efficiently than ani about 16 calories of digestible energy more widespread. Louis M. Thompson, mals metabolize feed," he says. "Thus, for each calorie of human or animal en associate dean for agriculture at Iowa the comparatively scarce and expensive ergy spent in production. State University, told the AAAS audi fuel energy is used more efficiently in With the addition of cultural energy, ence that the effect of the world's agriculture than the free and plentiful farm outputs rose. However, Dr. "green revolution" in crop productivity solar energy. Heichel notes, "It is striking that by starting in 1966 has been to increase "Although the theoretical efficiency 1915, the corn farmers in Pennsylvania livestock production greatly. Animals of photosynthesis is about 13%, waste and Iowa who were using a higher level are the effective grain outlet when ful respiration, or release of carbon of technology were producing only grain output exceeds the 400 pounds dioxide from photosynthetic products, about 30% more digestible energy than per person per year needed for human and incomplete capture of sunlight by the New Guinea savage or Philippine use. leaves throughout the growing season peasant." Could the resulting pressure on ener restrict the observed efficiency of most With greatly increased cultural ener gy used for food be alleviated by sub plants to the range of 0.1 to 3%." Actu gy inputs, modern farms have pushed stituting green manure crops such as al digestible calories in harvested up production to a maximum of more sweet clover or just manure itself for plants come to even less, 0.4% of sun than 30,000 megacalories of digestible fertilizer? Dr. Heichel doesn't think so. light calories for the relatively efficient energy per acre per year for silage corn He rules out clover for reasons of insuf plant, corn. at a cultural energy input of about ficient reserve cropland to produce it There may be some gains possible in 5000 megacalories. However, this in and insufficient quantities of potential solar energy efficiency in plants. Dr. creased yield now represents a gain of nutrients, such as phosphorus, potassi Robert S. Loomis of the University of just 5 to 6 times cultural energy input. um, and trace elements. As for animal California, Davis, told the AAAS ses Dr. Heichel summarizes, "For a sig manure, he acknowledges that the en sion that a great deal of progress has nificant number of modern cropping ergy considerations are attractive but been made in understanding photosyn systems, a 10- to 50-fold increase in the says that the cost of transportation thesis. Part of this new knowledge in expenditure of cultural energy per acre from the major production sites, ani dicates that very few agricultural sys yields only a doubling or tripling of di mal feedlots, currently prevents an tems operate at maximum conversion gestible energy per acre compared with economically sound substitution. of solar to chemical energy because of the more primitive or less sophisticated Wrapping up the meeting session, economic practices such as harvesting examples. Thus, substantial expendi Dr. Perry R. Stout of the University of after a very short time of peak leaf tures of cultural energy often fail to California, Davis, concluded, "We are canopy. Research suggests that more produce corresponding increases in stuck with high-energy agriculture. We complete coverage of the energy-ab yield. This response suggests that pro can't afford to drop it out." sorbing land by a crop could lead to gressively larger expenditures of cul Still, session arranger Clarence F. improvements, such as a one-third re tural energy produce less crop output. Kelly, professor emeritus at the Uni duction in acreage for lettuce. Diminishing returns clearly result dur versity of California, Berkeley, left The addition of cultural energy in ing use of cultural energy." conferees with an interesting thesis: puts to the sun's rays has led to higher Specifically, Dr. Heichel finds that "Agriculture has solved every problem crop yields but not by a proportionate digestible energy yields decline with that came along but with excessive use amount. Dr. Heichel has calculated expenditures of cultural energy over of fossil fuel. Now we have created a cultural energy efficiency in 15 crops the optimum of 5000 megacalories per problem that can't be solved by use of ranging from primitive rice in Asia to acre per year. Good illustrations are more energy."
Increasing cultural energy leads to diminishing returns
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C&EN March 11, 1974
