I/EC Feature Lecture
Chemistry, Chemical
Engineering,
and Agriculture Agriculture in the United States has t w o striking features: w i d e diversity a n d g r e a t productivity. W e l e a d the w o r l d in production o f most major crops a n d only three o f the 12 major w o r l d f o o d crops a r e not g r o w n here commercially. A w e a j t h o f natural resources is the basis o f this agricultural diversity and productivity, a n d through science a n d the technology arising from it, w e h a v e been a b l e to e x t e n d the usefulness o f these r e sources enormously. O v e r the past 5 0 years, application o f technology has transformed our farms,, resulting in a r e m a r k a b l e increase in production per acre, a n d p e r animal, a n d in total output. M a n y spectacular gains have come in the past 2 0 years. Today, our farms produce a b o u t one and one-half times as much as in the years immediately b e f o r e W o r l d W a r II. Crop production has increased a b o u t 3 2 % p e r acre, livestock 3 0 % p e r animal, t o t a l output a b o u t 48%. W h i l e these increases have been m a d e , farmers a n d number of farms have decreased. The farmers who r e m a i n e d have achieved r e c o r d - b r e a k ing harvests on a b o u t the same a c r e a g e a n d w i t h 3 0 % less l a b o r b y increasing investments in both c a p i t a l goods and o p e r a t i n g expenses. A l a r g e share o f the money has gone for p o w e r e q u i p ment. O n e result, during that past 3 0 years o f the shift t o machines, has been the release o f a b o u t 7 0 million acres o f cropland formerly used to p r o v i d e f e e d for horses and mules. Mechanization has also led t o b e t t e r t i l l a g e a n d more thorough methods o f a p p l y i n g insecticides a n d fertilizers. These, in turn, h a v e h e l p e d to boost yields. This is the story o f how chemistry a n d chemical engineering fit into this picture.
28 A
M,
.ARKED IMPROVEMENTS have been made in recent years by the plant breeders in every major crop—in varieties adapted to production under extremes of temperature, drought or moisture, that make more efficient use of fertilizer, that carry resistance to various farm hazards that once took heavy toll. Hybrid corn, one of the spectacular developments in plant research, js now grown on more than 50% of the land in this country planted to the corn crop. Along with such improved planting materials developed by the agronomists, chemistry and chemical engineering have given the farmer a wealth of powerful new chemicals for controlling pests and for other farm jobs. In the past 15 years the agricultural chemicals industry has expanded its output from some 50 basic products to more than 200. Products placed on the market within 10 years account for between 80 and 90% of today's sales. A measure of the improvement in chemicals can be seen in a comparison of our methods of grasshopper
control in the mid-thirties and today. Twenty years ago, we were getting 60 to 80% control per acre with 20 pounds of bait—a mixture of sodium arsenite, bran, and sawdust. Materials handling was a problem ; 150 acres of treatment was a good day's work. Today, 2 ounces of poison in a gallon of oil per acre will kill about 95 to 9 7 % of all species of grasshoppers. With planes, it is possible to treat 8000 to 9000 acres per day. Over-all per-acre costs are half those of 1935. New ideas of soil management and widespread acceptance of the value of fertilizer have played a dominant role in increase of agricultural productivity. Farmers today use more than four times as much fertilizer as in the years preceding World War II—material of higher analysis and more easily handled. New knowledge of the role of various nutrients in plant growth, through research with radioisotopes and other techniques, makes it possible for the farmer to apply fertilizer with increasing precision.
Byron T. Shaw W h e n the D i v i s i o n of Industrial a n d Engineering Chemistry decided to h a v e as the subject of its fourth Feature Lecture " T h e I m p a c t of Chemistry a n d C h e m i c a l Engineering on Production a n d U t i l i z a t i o n of A g r i c u l t u r a l C o m m o d i t i e s , " t h e y quite n a t u r a l l y turned to Byron T. S h a w , administrator of the USDA's A g r i c u l t u r a l Research Service. Dr. S h a w is a g r a d u a t e of O h i o State in soil physics, a n d has b e e n in the U S D A research p r o g r a m since 1 9 4 7 . He has been h e a d i n g the Department's research activities a n d related control a n d r e g u latory programs since 1 9 5 2 , received the Department's Distinguished Service A w a r d in 1 9 5 5 , a n d is c h a i r m a n of the President's Interdepartmental C o m m i t t e e on Scientific Research a n d D e v e l o p ment.
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Livestock p r o d u c t i o n also reflects c o n t i n u i n g advances o n m a n y sci entific fronts. R e s e a r c h in genetics has given us fast-gaining a n i m a l s tailored to the d e m a n d s of the market. T h e same progress in technology t h a t has m a d e it possible to i m p r o v e a n d extend this nation's agriculture has led to s h a r p c u r t a i l m e n t of m a r k e t s for n e w agricultural p r o d ucts. Generally, the effect has been to diminish outlets for agricultural commodities as r a w materials. Al cohol, glycerol, some resins, a n d m a n y other materials once m a d e ex clusively from farm p r o d u c t s a r e now m a d e from n a t u r a l gas a n d petroleum refinery by-products. W i t h i n the past few years, detergents from petroleum h a v e all b u t c r o w d e d soap m a d e from agricultural fats a n d oils off the grocery shelves. Plastics h a v e moved into the m a r k e t for hides a n d leather goods. Synthetic fibers are m a k i n g steady inroads into the m a r k e t for cotton a n d offer in creasing competition for wool. T h e result is a n i m b a l a n c e of supply a n d d e m a n d in fats a n d oils, hides, a n d other products.
studies t h a t will help c h a n n e l agri cultural productivity into use. W e are m o v i n g forward on these assumptions : • A steadily expanding market for agricultural commodities. Agricul ture must continue its technological advances in productivity, if the farmer is to keep pace with workers in other sections of the economy and if we are to realize the full benefits of our resources. • Opportunities for increasing total food consumption will be tied closely to population growth in this country and throughout the world. Over the past 15 years, agricultural produc tion in the United States has run somewhat ahead of population in crease. Application of technology to agriculture in other parts of the world will increase productivity, and the world food market will become in creasingly competitive. • One of the prospects for expanding the market for farm products, both at home and abroad, is through research that changes the character of food consumption. A marked trend to livestock products would mean sharp increases in consumption of grains and forages. • There is an encouraging potential for expanding the agricultural market through research to develop com pletely new industrial uses for farm and forest products.
T h i s a d v a n c i n g front of science has given us, for the first time, a b r o a d base of knowledge for projecting fu ture food r e q u i r e m e n t s , the re sources w e m a y d r a w u p o n to m e e t t h e m , a n d some of the barriers t h a t m a y stand in the way. D u r i n g t h e past few m o n t h s , the Agricultural R e s e a r c h Service has been m a k i n g a n intensive study of the d e m a n d for agricultural commodities t h a t m a y be anticipated in the next 5 to 20 years, the supply now in prospect, a n d the implications for research. O u r concern is to establish guidelines a n d set u p priorities for systematic
increasing emphasis to the search for new uses of farm a n d forest p r o d ucts. T h e task immediately before us is to extend the farmers' markets by finding new ways of fitting agri cultural commodities to industry's needs. Chemistry a n d chemical en gineering will play a d o m i n a n t role in these efforts. O n e of the chief barriers to prog ress in the search for new uses is o u r limited knowledge of the composition a n d properties of agricultural c o m modities. Even t h o u g h agricultural chemists h a v e been assembling in formation in this field for more t h a n a h u n d r e d years, we still h a v e only a partial picture, grossly i n a d e q u a t e for present needs. W e d o h a v e now m a n y illuminating new concepts, powerful tools, a n d precise tech niques for studying the composition a n d properties of all materials. E a c h of these major elements of agricultural commodities m a y be m o r e fully characterized. T h e r e are m a n y m i n o r constituents t h a t m a y give agricultural commodities u n i q u e properties. These need to be studied exhaustively. W e are e m b a r k i n g on a b r o a d study of b o t h major a n d m i n o r constituents. This a p p r o a c h has already opened u p e n c o u r a g i n g prospects for new agricultural markets. O u r research o n w h e a t a n d other cereal grains as a source of industrial r a w materials is a case in point. I n working w i t h these crops, t h e scientists h a v e been chiefly concerned w i t h the starch t h a t accounts for a b o u t two thirds of the grain. T h e r e are lesser q u a n tities of protein, oil, nonstarch car bohydrates, a n d a variety of m i n o r constituents—many not fully c h a r acterized. Cereal starches are well k n o w n to
Impact of Chemistry and Chemical Engineering on Utilization I n sizing u p the j o b a h e a d , w e recognize t h a t the first responsibility of agriculture is to meet this c o u n try's needs for food, feed, a n d fiber. W e shall continue o u r long-term efforts to i m p r o v e these p r o d u c t s to suit the c h a n g i n g times. But w e must go beyond this responsibility. W i t h p r o d u c t i o n currently r u n n i n g a h e a d of c o n s u m p t i o n , we must give
All photographs and graphs courtesy of USOA
u. S.
POPULATION A N D FARM OUTPUT
%Of 1 9 1 0 - 1 ^ ^ ^ ^ ^ ^ ^ O u t Pu»
USE OF FATS AND OILS IN NONFOOD PRODUCTS
^
160 Population
Total.
V
Λ /
w^f— 19 10
1920
1930
1940
1950
19 50
VOL. 48, NO. 12
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DECEMBER 1956
29 A
DIALDEHYDE
STARCH
New Raw Material
Partial o f Complete Starch O x i d a t i o n
N e w M o d i f i e d Starches (Paper, Textiles, Tanning)
Chem. Modification (Polyamines, etc.)
N e w Polymers (Plastics)
O x i d a t i o n or Reduction Plus Hydrolysis
Poly alcohols. Hydroxy Acids (Alkyd Resins, Séquestrants)
O x i d a t i o n or N o Hydrolysis
N e w Polymers, Polyelectrolytes (Thickening, Stabilizing Agents)
«««grains
industry. The paper and textile industries use some 900 million pounds of them each year. In trying to extend this market, department scientists have developed a promising laboratory method for converting grain starch into dialdehyde starches —starches radically different in properties from the starting material, and from other commercial chemicals. Their highly reactive nature makes them of value both as versatile products with many applications
Reduction
and as a source of other chemicals. They appear to act as a rapid and effective vegetable-type tanning agent for leather. They can be converted into a strong, tough plastic. The next step is to perfect a commercial process for the conversion of grain starch to dialdehyde starches. We are working on this problem. We would like to enlist the help of the country's industrial scientists. Its solution would help to find outlets for agriculture in the markets
G e l l e d paints (right), m a d e with p o l y a m i d e resins d e v e l o p e d b y the Northern Utilization Research Branch, d o not d r i p or run. Both paints shown a r e flat interior w a l l finishes. Brushes were d i p p e d simultaneously, l i f t e d , and immediately photographed 30 A
INDUSTRIAL AND ENGINEERING CHEMISTRY
that now absorb 240 million pounds of imported vegetable tannins and 800 million pounds of plastics. Our work on starches illustrates a second approach in the search for new opportunities to turn agricultural commodities to wider industrial use. This is to examine the product in the light of the needs of a specific industry and see how it may be altered to meet those needs. We are watching the increasing shortage of domestic pulp supplies. With a current production of a little more than 30 million tons of paper annually, manufacturers are importing 8 million tons of pulp each year. They will be in the market for much larger supplies as they expand production—according to present plans—between 6 and 7 million tons annually by 1958. Research in forest products holds opportunities for meeting a big share of the demand. One potential is through the development of high yielding processes for pulping mixed species, particularly hardwoods. With conventional processes, these species yield between 40 and 50% pulp. A semichemical process developed by the Forest Service yields 75%. A cold-soda process, also developed in this research, may provide yields up to 90%. The process can be installed in plants requiring far less capital investment than those now used for this purpose. Utilization research suggests also that starch or starch products with superior strength and adhesion properties can be used to supplement or extend the supply of pulp. Methods have been devised for improving
the adhesion and water resistance of ordinary starch and starch products incorporated into pulp products. We are also giving increasing attention to techniques for incorporating the optimum amounts of these starches needed to modify paper and paper products. These problems must be solved before the potential market for cereal starches in the pulp and paper industry can be realized. Some of the most promising leads in this work have to do with the amylose fraction of starch. The common cereal starches contain 20 to 30% amylose. This will form films comparable in strength to those made by the regeneration of dissolved wood fibers. Chemical derivatives, prepared in the laboratory, have also formed films and fibers with a high degree of strength and water resistance. This suggests that the incorporation of amylose or its derivatives into paper or paper products would contribute desirable strength and other tensile properties. But before amylose can be used in this way, we will have to find more abundant sources of made-to-order starch with high amylose content or develop practical methods of fractionating it. In agricultural research, we've made encouraging progress in the first approach. We have coming into production new corn hybrids with much higher amylose content than those now commonly grown. We are still hard at work on the second alternative. Here, industrial chemists and chemical engineers can make valued contributions in research on new methods of fractionating starch. Our own efforts will be directed to more intensive study of the optimum conditions for separating high-amylose starch and developing practical methods of preparing films from these and other starches and their derivatives. Another promising lead for new industrial uses of cereal starches came out of our research to develop mass production methods for penicillin. Our experiences with the fermentation of grain to produce penicillin, dextran, and vitamins B2 and B12 indicate the versatility of this approach. Progress in this work would open the vast and growing market in high polymer materials to the major agricultural commodities.
From the research at the Northern Utilization Research Branch on new uses for cereal grains has come the development of a transparent film from the starch fraction, amylose. A chemist is peeling the d r i e d film from the casting surface where a hot solution of amylose in w a t e r has been uniformly spread to the desired thickness
The increasing diversity of organisms now available for fermentation and the growing assortment of starting materials have opened a number of possibilities for new commercial applications. We have increasing evidence that many high
polymers of potential Industrial value can be produced. Research on fermentation action is steadily improving another good yield route to new industrial markets for grains, wood, and other agricultural commodities, as citric, glu-
A pipelike o r g a n instrument reveals the complex structural patterns of our v e g e t a b l e oils. Solvent is a d d e d to 2 0 0 - t u b e C r a i g Post countercurrent distribution a p p a r a t u s , now giving us a new look at v e g e t a b l e oil structure VOL. 43, NO. 12
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DECEMBER 1956
31 A
USDA Paint chemist A. J. Lewis inspects the " w e a t h e r i n g fence," the panels of which have been coated with paints m a d e from soybean oil that has undergone various refining treatments
conic, and other organic acids. Certain of these acids are already being used in special rubbers, plastics, industrial finishes, and as cleaning agents. One company is using a process developed in our research to make 3 million pounds a year of acid derivatives for washing bottles and milk cans and in aluminum etching compounds. We have only scratched the surface in this research. If these materials are to be more widely used, we must find ways to lower the costs of producing them. It is highlyprobable that levulinic acid can be made from wood at a cost that would be competitive with other sources. It is now an expensive laboratory curiosity. In August, I&EC (pages 1330 to 1341) published a detailed study of the levulinic acid picture. We are making progress in developing more economic methods of producing both citric and fumerie acids. Our findings suggest that these and other organic acids would find markets in the manufacture of special types of synthetic rubber and plastics. Much more research is needed to find new applications for the organic acids and their derivatives as chemicals, raw materials, and plastics. We need the help of men in industry who draw up the specifications for raw materials. 32 A
The past 15 years have brought many changes to markets for the agricultural commodities that, through history, have had widest industrial use—fats and oils. The supply has increased at an unparalleled rate—up 7 5 % over prewar levels. Since 1950, production has averaged 12.5 billion pounds a year. In 1955, it was nearly 13.7 billion pounds. This reflects both the impact of technology on many phases of agriculture and the entrance of petroleum products into the chief industrial market of agricultural fats and oils—the manufacture of soap. Opportunities for vegetable oils in another major market have been drastically curtailed in the past 20 years. As in the case of soap, the force behind this change is industrial research that has brought products from coal and petroleum into the picture. The amount of vegetable oils in a gallon of paint has dropped steadily. It was 2.4 pounds in 1936. Now it is 1.4. If the composition of our paints were the same now as in 1936, this market would be using a half billion more pounds of vegetable oils. In work now in progress, we are seeking to determine the chemical constituents in oil responsible for its quality. The next step is to discover the chemical reactions that will
INDUSTRIAL AND ENGINEERING CHEMISTRY
convert these constituents into improved materials. We have made chemically modified oils that bake rapidly to give hard and durable finishes. The new products are based on agricultural materials that are available commercially. In the laboratory, they can be readily prepared in good yields. The reduced demands for agricultural fats and oils on the soap and paint markets represent serious losses to farmers and businessmen engaged in the processing and distribution of these commodities. However, other industrial uses have helped to offset these declines. Some 60 million pounds are being used by the chemical industry in applications that were developed in our utilization research. Among these is a resin from soybean oil that was first used for heat-sealing glassine paper and other food packaging materials. Later, a paint manufacturer found the resin would give a gelled paint and today it is being used by more than 30 companies in making paints that do not drip. About 25 million pounds of tallow are used annually as emulsifiers in synthetic rubber. Another large outlet for agricultural fats and oils is in the fast-moving plastics industry. Certain derivatives of animal fats make excellent starting materials for the synthesis of plasticizers. One fat-based material developed in our laboratories is being used—at the rate of 35 million pounds a year—in the production of vinyl plastics. Another development in our research is a completely new fat-based vinyl stéarate. This forms a plastic in which the softener is chemically bound to the base. The process increases the durability of the plastic and prevents its separation from the plasticizers. It s now being used in pilot-scale production. More recently, we have discovered derivatives of soybean oil that may prove superior to plasticizers now on the market. There is also evidence that agricultural oils may be used to advantage in the manufacture of detergents. Some of the first synthetic detergents were tallow-based. One product, widely sold today, contains a fat-based compound that constitutes 2 5 % of the active ingredient. O u r most encouraging progress has been in the development of detergents from animal fats, that, in the
laboratory, appear highly promising for industrial application. A large meat packing firm is now producing two of these fat-based detergents on a pilot scale. These should find wide acceptance as surface-active agents. More study is needed to produce fatbased detergents that meet household needs for solubility in hard water. Many of the opportunities to use our agricultural resources to greater advantage can be realized through research on processing methods. This approach is of particular interest for the fiber crops. In cotton, the basic principles used today in cleaning, carding, spinning, and weaving are—almost without exception—those first used more than a hundred years ago. They have served well. But they are no longer adequate for a crop that is being increasingly mechanized on the production side and must compete as finished goods not only with synthetic fibers, but also with paper, jute, and plastics. A major share of our utilization research on cotton is concerned with chemical and mechanical processes to improve the natural qualities of the fiber and to add qualities for which there is a demand. An example of this approach can be seen in our efforts to give canvas a longer
life. Our objective was to develop treatments that increased resistance to sunlight, mildew, and rot. This has been achieved by combining two processes—vat dyeing and partial acetylation. The treatment does not add substantially to the weight of the fabric and it promises to double or triple the life of the canvas. These are only a few of the new opportunities we see for agricultural commodities in industry. There are many applications that could be made with present analytical techniques and processing methods. We think that the most favorable prospects for turning farm surpluses to industrial use will be found in many comparatively small outlets. In the aggregate, these will care for large volumes of commodities. We need a much clearer picture of the economics involved. In taking the guesswork out of farming, science and technology have helped to assure billion-bushel crops. Can these be produced at a cost that will be attractive to industry and still pay adequate returns to the farmer? We need continuing information on the size of the market for industrial uses and what this requires in terms of farm output. The broadening front of chemistry and chemical engineering offers many challenging opportunities to
study agricultural commodities in the light of industrial needs. In recognition of this, the Federal Government is increasing investments in utilization research on farm and forest products in the Department of Agriculture. In the past 10 years, appropriations have doubled, to $16.1 million for the current fiscal year. Although a large share of the funds goes into studies designed to enhance farm products as food, we are steadily expanding our search for new industrial applications. A recent development that promises to lend force to our utilization work is the authorization by the 84th Congress of a five-man bipartisan commission on New Industrial Uses for Farm and Forest Products. In pressing forward in our search for new industrial uses for agricultural commodities, we will continue to have the cooperation of many firms closely allied to agriculture. They have a long and brilliant record of finding new uses for farm commodities. Many of our most profitable markets came through the efforts of processing firms to turn wastes and residues into valued byproducts. Along with these industrialists, we would like to enlist the interest of the other leaders in industry, who are not now closely associated with agriculture. As technology increases agricultural efficiency, the products of our farms and forest should become increasingly competitive. New knowledge of chemistry is making it possible to modify these materials to fit a wide range of needs. We have only begun to explore the potential. Forecast o f Agricultural Chemicals Required b y 1 9 7 5
Plastic articles stabilized with f a t t y plasticizers
Today, our immediate concern is to make full use of our immense agricultural productivity. But we must also look ahead, to the time when an increasing population will require further increases in output of our farms and forests. The projected requirements for 1975, according to present estimates, call for an output more than a fourth greater than the record production of 1955. Fertilizers. We expect consumption of plant nutrients in fertilizers to reach a level of 10 to 12 million tons by 1975—an increase of VOL. 48, NO. 12
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DECEMBER 1956
33 A
75 to 1 0 0 % over c u r r e n t use. O u r forecast is based on these considerations: 1.
Consumption today is about four times that of the 1935-1939 average and nearly 1 3 / 4 times as much as the average of 1947-1949.
2.
Although there have been marked increases in the use of fertilizers on the individual farm, we have not reached the optimum, and most farmers today would find it profitable to use more fertilizer.
3.
The United States has large resources of raw materials for fertilizer and agricultural lime and excellent sources of energy to process them.
4.
Although science and technology will continue to bring changes in our food and our eating habits, we do not anticipate striking alterations that would reduce the demand for fertilizers in the next 20 years.
I n d r a w i n g u p plans for agricultural research on fertilizer p r o b lems, our m a i n concern is to provide the farmer with m o r e efficient m a terials a n d techniques a n d e q u i p m e n t for p u t t i n g t h e m to use. This involves chemical a n d chemical engineering research along several lines. First, in continued i m p r o v e m e n t s in the plant n u t r i e n t content of fertilizers. W h i l e this has risen sharply over the years a n d now averages 2 8 % it has not reached the limit of possible gain. Increases in p l a n t nutrient content offer a n effective m e a n s of c u t t i n g farm costs for fertilizer. W e also see opportunities for improvements in the p r i m a r y nutrients of fertilizer—nitrogen, phosphoric acid, a n d potash. O n e of these is in the d e v e l o p m e n t of forms of nitrogen with low solubility. T h e quickacting nitrogen fertilizers, n o w available, leach rapidly. T h e farmer must m a k e several applications to get the effects t h r o u g h o u t the season. A good start has been m a d e in the d e v e l o p m e n t of slow-acting products in research on urea-formaldehyde c o m p o u n d s . W i t h c o m p o u n d s now u n d e r study, a single massive dose will supply e n o u g h nitrogen to meet r e q u i r e m e n t s of a long-season crop. A d d i t i o n a l work is needed to improve the efficiency further a n d lower the cost of these n e w types of nitrogen. I n m a n y sections of the country, it would be a d v a n t a g e o u s to h a v e less soluble forms of potash. This would r e d u c e present losses from leaching a n d help prevent excessive potash consumption, n o w a p r o b l e m 34 A
in alfalfa a n d certain other crops. T h e r e is also a need for low-cost carrier to replace potassium chloride for crops t h a t react unfavorably to the chloride ion. O n t h e p h o s p h a t e side of the story, there are a n u m b e r of comp o u n d s u n d e r study that show p r o m ise. A m o n g these are the highly concentrated calcium m c t a p h o s p h a t e ( 6 3 % P2O5), d i a m m o n i u m phosphate ( 2 1 % N, 5 3 % P 2 0 6 ) , and ammonium metaphosphate ( 1 7 % N, 7 3 % P2O5). T h e i r sphere of usefulness needs to be further defined. A l o n g with i m p r o v e m e n t s in plant nutrient content, there are challenging opportunities to e n h a n c e the physical m a k e - u p of solid fertilizers a n d their performance in storage a n d h a n d l i n g from the factory to the field. H e r e , too, a good start has been m a d e w i t h g r a n u l a r p r o d ucts t h a t h a v e m u c h less tendency to cake a n d h a r d e n d u r i n g storage a n d t h a t distribute easily a n d u n i formly in the field. M u c h m o r e work is needed on the technology of these products. T h e success of liquid fertilizers such as a n h y d r o u s a m m o n i a is reflected in their widespread use. Cost per unit for a p p l y i n g these m a t e rials in m a n y parts of the c o u n t r y is lower t h a n for solid fertilizers. H o w ever, a n u m b e r of problems must be solved before these a n d some of the new m u l t i n u t r i e n t solutions c a n be used efficiently. O n e of the persistent difficulties still to be overcome in the use of m u l t i n u t r i e n t solutions is the salting out a t atmospheric temperatures. T h e new higher analysis fertilizers also call for e q u i p m e n t t h a t applies t h e m with a high degree of precision. T h i s is a key to the economic use of fertilizers. C o n t i n u i n g research o n fertilizer rates, u n d e r widely varied conditions t h r o u g h o u t the c o u n t r y , is giving us a picture of the rates needed for different levels of yield in a specific e n v i r o n m e n t . T h i s is helping to establish guidelines for estimating returns per dollar invested in fertilizer. These, in t u r n , point the w a y to m o r e profitable use of fertilizer on b o t h small farms a n d large commercial operations. T h e y will be a n i m p o r t a n t force in exp a n d i n g the m a r k e t for fertilizers. Pesticides. T h e g r o w t h r a t e for pesticide consumption over the next 20 years is not expected to be as large as for fertilizers. T h e outlook is for it to increase at a slightly m o r e rapid
INDUSTRIAL AND ENGINEERING CHEMISTRY
r a t e t h a n the g r o w t h in h u m a n p o p u lation. T h i s would indicate a 1975 level of pesticide c o n s u m p t i o n between 40 a n d 5 0 % over t h a t of 1953. T h e forecast takes two influences into account. First, growers are becoming increasingly a w a r e of the role of pesticides in profitable farming. Second, we anticipate considerable progress in the developm e n t of herbicides, fungicides, a n d nematocides to control specific pest problems t h a t d o not yield to present materials. As a result of these new materials, there will be m a r k e d shifts in the kinds of pesticides used a n d a proportionately greater increase in herbicides a n d nematocides t h a n insecticides. W e d o not expect these shifts to affect the trend in over-all c o n s u m p t i o n . O p p o r t u n i t i e s for gains in new pesticide materials a p p e a r most promising in research in chemicals t h a t are highly toxic to pests a n d have a low order of toxicity for m a n a n d w a r m - b l o o d e d animals. W e can look forward to advances in our knowledge of the n a t u r e of resistance in various pests to chemical controls. N e w materials a n d techniques will call for continuing modifications a n d i m p r o v e m e n t s in applicators. I m p o r t a n t gains in the foreseeable future will be m a d e in the discovery a n d use of parasites, predators, a n d diseases to control agricultural pests by biological means. Resistant crop varieties will continue to play a n i m p o r t a n t role. Still a n o t h e r trend of significance to this audience is the increasing d e p e n d e n c e on specialists to m a n a g e c a m p a i g n s against pests from diagnosis of the p r o b l e m right on t h r o u g h to effective control. I n o u r opinion, chemicals will c o n t i n u e to b e the m a i n s t a y in pest control. T h e outlook, then, is for steadily increasing use of chemicals in agric u l t u r e in the years a h e a d . The concern, in the i m m e d i a t e future, is with chemicals t h a t will e n h a n c e p r o d u c t i o n efficiency. As time goes on a n d as o u r growing population increases the d e m a n d for food, interest will shift to chemicals t h a t will help increase production. Finally, we have reached a stage in scientific knowledge that makes it possible to t u r n rich a n d renewable products of farms a n d forests to a s t u n n i n g a r r a y of new uses. W e will be paced in this forward m a r c h b y n e w ideas, new materials, a n d new techniques from chemical a n d chemical engineering research.
