energy inputs to agriculture
Energy Inputs to Agriculture
Antony F.F. Boys (January 2005)
0. Introduction
The story of the use of fossil energy resources since the beginning of the Industrial Revolution over two hundred years ago is often told in terms of the development of our current modern, predominantly urban, lifestyles, characterized by the incredible scientific and technological progress of these two centuries. Not so often do we hear about how fossil energy resources, combined with scientific and technological progress, have changed the way we produce the food we need to survive. How much energy is being used in what form in agriculture? How has this come about historically, what does it mean, and where is it going in the mid-term future? This paper is an attempt to give a brief answer to these questions.
1. How fossil energy came to be used in agriculture
Energy, as we experience it in our lives, is a solar "gift". Life began on earth about 3.5 b yrs ago when certain chemical compounds became able to reproduce themselves through the ability to make direct use of incoming solar energy; autotrophs, which are able to produce their own energy through the direct use of solar energy. The development of the type of photosynthesis which releases oxygen, as in green plants today, occurred between 3 b and 2 b yrs ago.(1) Later in the evolutionary process, life forms not able to make direct use of solar energy (heterotrophs) emerged, and these were dependent for the energy for life on the autotrophs. They ate them. Thus emerges a picture of earth that existed up until the end of the last ice age, perhaps 15,000 years ago.
At that stage, mankind lived a "hunter-gatherer" existence. It is unsure when man became able to use fire (the conscious use of inanimate energy for cooking, defense and so on), but the archaeological record shows that fires were regularly used by about 40,000 yrs ago.(3) Agriculture, the conscious and organized use of plants and animals by mankind in an attempt to capture a larger fraction of solar energy income for human use, is thought to have begun around 10,000 yrs ago. This situation remains largely unchanged (a certain amount of technological innovation taking place in agriculture in the meantime – rice cultivation, the introduction of farming rotations, and so on) until about the middle of the 19th century when the work of chemists such as Justus von Liebig (4) resulted in the possibility of using inorganic chemicals as fertilizers. The industrial revolution also brought together the use of coal and machinery in the invention of the steam engine, which later found many applications as labor-saving technology in farming. In the 1840s, Rothamsted (UK) experiments showed that applications of nitrogen fertilizers offered the best path to higher grain crop yields, but it was not until 1887 that symbiotic nitrogen fixation in legumes was discovered. The big problem for agricultural progress at the end of the 19th century was that the ability to fix nitrogen by artificial means had not yet been invented.(5) The world currently has about 1.5 Gha of farmland under production.(6) and there is little room for expansion of this without the destruction of forests, wetlands and so on, or moving into inferior farmlands. Around 235 Mha of new farmland, mostly for wheat production, was created as the grasslands of North and South America, Australia, and Russia were brought under cultivation between 1850 and 1920. Yields were still low – about 1.5 ton/ha in the best European farming – but the population was rising, and the newly urban population was also beginning to consume more animal-derived foods – meat and dairy products. The land horizon was beginning to come into view, and it was recognized that only way to feed the growing population with its increasingly urban diet was to intensify the agricultural production of food on more or less existing farmland. Thus, William Crookes was led to proclaim in September 1898 that, "The fixation of nitrogen is vital to the progress of civilized humanity." (7)
Note on fossil fuel formation: Thecoal, formed from layers of plantremains generally in the CarboniferousPeriod 345-280 m yrs ago, and oil andnatural gas, believed to have beenformed from sediments of microscopicplanktons, or diatoms, mostly in theJurassic and Cretaceous Periods,190-65 m yrs ago, that we use as ourmajor energy sources now, has itsenergetic origin in solar radiation, asdoes all life.(2)
Note on population: Although increases anddecreases in (the rate of growth of) humanpopulations is a complex matter involving manysocio-economic factors, the basic physiologicalfactor involved, all other factors being equal – nonatural or man-made disasters, for instance – mustbe the relative availability of food.
That the humanpopulation of the world has risen from 1 billionearly in the 19th century to over 6 billion at thebeginning of the 21st century must be due in nosmall part to the ability of man to appropriate alarger share of incoming solar energy through theapplication (as machinery or chemicals) ofinanimate energy forms, primarily fossil energy. Crookes did not have very long to wait. Fritz Haber (1868-1934) began work on ammonia synthesis from hydrogen and nitrogen (N2 + 3H2 ↔ 2NH3) in the summer of 1904. Success came on July 2, 1909 in an experiment which indicated ammonia yields of about 10% at 10 Mpa (10 million pascals – about 100 atmospheres) and 500oC. This was carried out with an experimental converter, a pressurized tube 75 cm tall and 13 cm in diameter, in Haber's experimental laboratory.(8) This apparatus was upgraded into a pilot plant device by Carl Bosch (1874-1940). Bosch's work was carried out so quickly that planning for a commercial plant of 10 t NH3/day began in April 1911, but was upgraded to 30 t NH3/day in November 1911. Construction at Oppau began May 7 1912, and was completed on September 9, 1913 (the day of first NH3 production). NH3 was converted to ammonium sulphate for fertilizer. However, war broke out on August 4, 1914, and NH3 production was redirected to the production of nitric acid for war munitions. A new and very large ammonia plant, built at Leuna, was completed in April 1917. This represented the completion of "preparations" for supplying the world with artificial nitrogen fertilizers, but these did not become the dominant means of supplying fixed nitrogen for agriculture till the 1930s, rapid increase in their use coming in the 1950s and onwards.(9) The next step in the food and energy story is the introduction of hybrid (high yielding varieties – HYV) varieties of the main staple grains, maize, wheat, and rice. The first commercial hybrid maize was introduced in the US in 1929. The higher yields of the new varieties of maize made it possible to increase land productivity. By the end of WWII, hybrid maize had replaced traditional varieties. In itself, this does not increase energy consumption, but besides the fact that the farmers must buy new seed each year, hybrid maize introduced an array of corollary farm products such as fertilizer, insecticides, herbicides, and other pesticides; the equipment used to apply these chemicals; and the enormous and enormously expensive machinery used to harvest maize. The higher yield of the hybrids had the overall effect of sustaining chronic overproduction, thus forcing farm prices down as cash inputs increased, contributing to the degeneration of soil quality, and helping to sustain human population increase through the increased availability of cheap food. In other words, by the 1930s the "modernization" (industrialization, mechanization and chemicalization – energy intensification) of agriculture in the US was basically complete with respect to maize, and this would soon spread to other advanced nations and other important crops. However, disease epidemics began to appear in US maize in the 1970s due to genetic similarity of maize crops grown over vast areas, and due to the decline in disease resistance of the plants resulting from the deterioration of the soil after several decades of chemical fertilizer use. This has stimulated the increasing use of toxic pesticides, and the race against nature to develop disease- and pest-resistant varieties, resulting in the development recently of genetically modified crops.(10)
2. The Green Revolution
In 1944, Norman Borlaug arrived at the International Center for the Improvement of Maize and Wheat (CIMMYT) near Mexico City. He was working on HYV wheat, but breeders found that the varieties that would produce increased yields when supplied with increasing amounts of nitrogen fertilizer caused the wheat plants to "lodge", limiting both the amount of nitrogen that could be used and the resulting yields.
To solve this problem Borlaug experimented with Norin 10 (originating in Japan as a cross between a Japanese variety called Daruma, and an American wheat variety called Fultz), a Japanese "dwarf" variety.
He incorporated the "dwarfing gene" from Norin 10 into the Mexican wheat varieties he was studying. The result was a shorter wheat that could withstand far greater fertilizer applications without lodging. The new wheats were 20 to 40 inches tall, compared to 50 to 60 inches for traditional varieties. They had stronger stems and roots, more flowering heads, and more grains per head – larger harvesting index. This was the beginning of the Green Revolution (GR).(11).
The process was soon repeated with rice at the IRRI in the Philippines. A dwarf variety of rice, IR8, was introduced to Asian farmers in 1966 and immediately boosted rice yields and harvests.
However, IR8 quickly proved to be susceptible to a variety of pests and diseases and was followed in succeeding years by IR20, IR36, IR60, IR62, and IR64 in order to stay ahead of the pests and diseases. The result of the GR however was the "modernization" (industrialization, mechanization and chemicalization – energy intensification) of agriculture in much of the rest of the world, the developing countries. As the GR package requires fertilizers, irrigation, pesticides, and inevitably leads to the use of machinery.(12)
From the end of WWII until about the mid-1980s, the introduction of high-yield crops and energy intensive agriculture (the GR) led to increased crop production.
World grain output expanded by a factor of 2.6 in this period, while the world population doubled from 2.5 to 5 billion.
The success of the Green Revolution lay primarily in its increased use of fossil energy for fertilizers, pesticides, and irrigation to raise crops as well as in improved seed. It greatly increased the energy-intensiveness of agricultural production, in some cases by 100 fold
or more.(13) Large grain yield increases resulted in a massive improvement in land productivity.
A secondary effect was that large areas of cropland could be continuously monocropped, eliminating the need for traditional rotation systems. Farm machinery was widely introduced, thereby raising labor productivity at the expense of use of more fossil fuels.
However, the GR engendered several problems, briefly:
- - reduction of biodiversity as HYVs replaced traditional crop varieties,
- - destruction of soil fertility through the heavy use of chemical fertilizers,
- - increase in nutritional imbalances due to monocropping and abandoning of rotational practices,
- - chemical contamination and pollution with the resultant effects on the environment and human health (14)
An important social consequence of the GR was that it often did not directly help to relieve poverty, as it was anticipated that it would. In general, the GR benefited the better-off farmers who could afford the whole GR package of seeds and chemicals and who had access to better quality and irrigated land, and preferential access to finance and credit.
Increased harvests increased the incomes of these farmers, despite falling prices due to increased production, and allowed them to take over the lands of their poorer farmer neighbors.
The poorer farmers frequently had to go into debt to buy the new seeds and chemicals, which they were unable to repay because of falling commodity prices.
They therefore had to sell their land. Better-off farmers might conceivably then employ the newly landless farmers on their expanded farms, but generally they did not, preferring to buy farm machinery instead, (15) sending the newly destitute off to the cities in search of employment.
For the better-off farmers, this situation continued favorably for some years, but more recently problems of reduced yields (reduced soil fertility following several years of chemical fertilizer use), pest and disease problems related to weakening plant health due to reduced soil fertility, and human health problems concerned with agricultural chemicals.
The need to continue on the proprietary seed and chemical treadmill (increasing cash inputs to crops) despite falling yields has been responsible for a general farmer impoverishment and indebtedness in many developing countries.
Individual farmers and farming groups in south and southeast Asia have, over the last 10-15 years, made progress in escaping this vicious circle by converting to organic farming methods.
Figure 1: O/I Ratios for 25 Rice Systems a-h = pre-industrial, i-r = semi-industrial, s-y = fully industrial
Figure 2: Yield/labor comparisons for 25 rice-growing systems
Energy Inputs to Agriculture
Antony F.F. Boys (January 2005)
0. Introduction
The story of the use of fossil energy resources since the beginning of the Industrial Revolution over two hundred years ago is often told in terms of the development of our current modern, predominantly urban, lifestyles, characterized by the incredible scientific and technological progress of these two centuries. Not so often do we hear about how fossil energy resources, combined with scientific and technological progress, have changed the way we produce the food we need to survive. How much energy is being used in what form in agriculture? How has this come about historically, what does it mean, and where is it going in the mid-term future? This paper is an attempt to give a brief answer to these questions.
1. How fossil energy came to be used in agriculture
Energy, as we experience it in our lives, is a solar "gift". Life began on earth about 3.5 b yrs ago when certain chemical compounds became able to reproduce themselves through the ability to make direct use of incoming solar energy; autotrophs, which are able to produce their own energy through the direct use of solar energy. The development of the type of photosynthesis which releases oxygen, as in green plants today, occurred between 3 b and 2 b yrs ago.(1) Later in the evolutionary process, life forms not able to make direct use of solar energy (heterotrophs) emerged, and these were dependent for the energy for life on the autotrophs. They ate them. Thus emerges a picture of earth that existed up until the end of the last ice age, perhaps 15,000 years ago.
At that stage, mankind lived a "hunter-gatherer" existence. It is unsure when man became able to use fire (the conscious use of inanimate energy for cooking, defense and so on), but the archaeological record shows that fires were regularly used by about 40,000 yrs ago.(3) Agriculture, the conscious and organized use of plants and animals by mankind in an attempt to capture a larger fraction of solar energy income for human use, is thought to have begun around 10,000 yrs ago. This situation remains largely unchanged (a certain amount of technological innovation taking place in agriculture in the meantime – rice cultivation, the introduction of farming rotations, and so on) until about the middle of the 19th century when the work of chemists such as Justus von Liebig (4) resulted in the possibility of using inorganic chemicals as fertilizers. The industrial revolution also brought together the use of coal and machinery in the invention of the steam engine, which later found many applications as labor-saving technology in farming. In the 1840s, Rothamsted (UK) experiments showed that applications of nitrogen fertilizers offered the best path to higher grain crop yields, but it was not until 1887 that symbiotic nitrogen fixation in legumes was discovered. The big problem for agricultural progress at the end of the 19th century was that the ability to fix nitrogen by artificial means had not yet been invented.(5) The world currently has about 1.5 Gha of farmland under production.(6) and there is little room for expansion of this without the destruction of forests, wetlands and so on, or moving into inferior farmlands. Around 235 Mha of new farmland, mostly for wheat production, was created as the grasslands of North and South America, Australia, and Russia were brought under cultivation between 1850 and 1920. Yields were still low – about 1.5 ton/ha in the best European farming – but the population was rising, and the newly urban population was also beginning to consume more animal-derived foods – meat and dairy products. The land horizon was beginning to come into view, and it was recognized that only way to feed the growing population with its increasingly urban diet was to intensify the agricultural production of food on more or less existing farmland. Thus, William Crookes was led to proclaim in September 1898 that, "The fixation of nitrogen is vital to the progress of civilized humanity." (7)
Note on fossil fuel formation: Thecoal, formed from layers of plantremains generally in the CarboniferousPeriod 345-280 m yrs ago, and oil andnatural gas, believed to have beenformed from sediments of microscopicplanktons, or diatoms, mostly in theJurassic and Cretaceous Periods,190-65 m yrs ago, that we use as ourmajor energy sources now, has itsenergetic origin in solar radiation, asdoes all life.(2)
Note on population: Although increases anddecreases in (the rate of growth of) humanpopulations is a complex matter involving manysocio-economic factors, the basic physiologicalfactor involved, all other factors being equal – nonatural or man-made disasters, for instance – mustbe the relative availability of food. That the humanpopulation of the world has risen from 1 billionearly in the 19th century to over 6 billion at thebeginning of the 21st century must be due in nosmall part to the ability of man to appropriate alarger share of incoming solar energy through theapplication (as machinery or chemicals) ofinanimate energy forms, primarily fossil energy. Crookes did not have very long to wait. Fritz Haber (1868-1934) began work on ammonia synthesis from hydrogen and nitrogen (N2 + 3H2 ↔ 2NH3) in the summer of 1904. Success came on July 2, 1909 in an experiment which indicated ammonia yields of about 10% at 10 Mpa (10 million pascals – about 100 atmospheres) and 500oC. This was carried out with an experimental converter, a pressurized tube 75 cm tall and 13 cm in diameter, in Haber's experimental laboratory.(8) This apparatus was upgraded into a pilot plant device by Carl Bosch (1874-1940). Bosch's work was carried out so quickly that planning for a commercial plant of 10 t NH3/day began in April 1911, but was upgraded to 30 t NH3/day in November 1911. Construction at Oppau began May 7 1912, and was completed on September 9, 1913 (the day of first NH3 production). NH3 was converted to ammonium sulphate for fertilizer. However, war broke out on August 4, 1914, and NH3 production was redirected to the production of nitric acid for war munitions. A new and very large ammonia plant, built at Leuna, was completed in April 1917. This represented the completion of "preparations" for supplying the world with artificial nitrogen fertilizers, but these did not become the dominant means of supplying fixed nitrogen for agriculture till the 1930s, rapid increase in their use coming in the 1950s and onwards.(9) The next step in the food and energy story is the introduction of hybrid (high yielding varieties – HYV) varieties of the main staple grains, maize, wheat, and rice. The first commercial hybrid maize was introduced in the US in 1929. The higher yields of the new varieties of maize made it possible to increase land productivity. By the end of WWII, hybrid maize had replaced traditional varieties. In itself, this does not increase energy consumption, but besides the fact that the farmers must buy new seed each year, hybrid maize introduced an array of corollary farm products such as fertilizer, insecticides, herbicides, and other pesticides; the equipment used to apply these chemicals; and the enormous and enormously expensive machinery used to harvest maize. The higher yield of the hybrids had the overall effect of sustaining chronic overproduction, thus forcing farm prices down as cash inputs increased, contributing to the degeneration of soil quality, and helping to sustain human population increase through the increased availability of cheap food. In other words, by the 1930s the "modernization" (industrialization, mechanization and chemicalization – energy intensification) of agriculture in the US was basically complete with respect to maize, and this would soon spread to other advanced nations and other important crops. However, disease epidemics began to appear in US maize in the 1970s due to genetic similarity of maize crops grown over vast areas, and due to the decline in disease resistance of the plants resulting from the deterioration of the soil after several decades of chemical fertilizer use. This has stimulated the increasing use of toxic pesticides, and the race against nature to develop disease- and pest-resistant varieties, resulting in the development recently of genetically modified crops.(10)
2. The Green Revolution
In 1944, Norman Borlaug arrived at the International Center for the Improvement of Maize and Wheat (CIMMYT) near Mexico City. He was working on HYV wheat, but breeders found that the varieties that would produce increased yields when supplied with increasing amounts of nitrogen fertilizer caused the wheat plants to "lodge", limiting both the amount of nitrogen that could be used and the resulting yields. To solve this problem Borlaug experimented with Norin 10 (originating in Japan as a cross between a Japanese variety called Daruma, and an American wheat variety called Fultz), a Japanese "dwarf" variety. He incorporated the "dwarfing gene" from Norin 10 into the Mexican wheat varieties he was studying. The result was a shorter wheat that could withstand far greater fertilizer applications without lodging. The new wheats were 20 to 40 inches tall, compared to 50 to 60 inches for traditional varieties. They had stronger stems and roots, more flowering heads, and more grains per head – larger harvesting index. This was the beginning of the Green Revolution (GR).(11).
The process was soon repeated with rice at the IRRI in the Philippines. A dwarf variety of rice, IR8, was introduced to Asian farmers in 1966 and immediately boosted rice yields and harvests. However, IR8 quickly proved to be susceptible to a variety of pests and diseases and was followed in succeeding years by IR20, IR36, IR60, IR62, and IR64 in order to stay ahead of the pests and diseases. The result of the GR however was the "modernization" (industrialization, mechanization and chemicalization – energy intensification) of agriculture in much of the rest of the world, the developing countries. As the GR package requires fertilizers, irrigation, pesticides, and inevitably leads to the use of machinery.(12)
From the end of WWII until about the mid-1980s, the introduction of high-yield crops and energy intensive agriculture (the GR) led to increased crop production. World grain output expanded by a factor of 2.6 in this period, while the world population doubled from 2.5 to 5 billion. The success of the Green Revolution lay primarily in its increased use of fossil energy for fertilizers, pesticides, and irrigation to raise crops as well as in improved seed. It greatly increased the energy-intensiveness of agricultural production, in some cases by 100 fold
or more.(13) Large grain yield increases resulted in a massive improvement in land productivity. A secondary effect was that large areas of cropland could be continuously monocropped, eliminating the need for traditional rotation systems. Farm machinery was widely introduced, thereby raising labor productivity at the expense of use of more fossil fuels.
However, the GR engendered several problems, briefly:
- - reduction of biodiversity as HYVs replaced traditional crop varieties,
- - destruction of soil fertility through the heavy use of chemical fertilizers,
- - increase in nutritional imbalances due to monocropping and abandoning of rotational practices,
- - chemical contamination and pollution with the resultant effects on the environment and human health (14)
An important social consequence of the GR was that it often did not directly help to relieve poverty, as it was anticipated that it would. In general, the GR benefited the better-off farmers who could afford the whole GR package of seeds and chemicals and who had access to better quality and irrigated land, and preferential access to finance and credit. Increased harvests increased the incomes of these farmers, despite falling prices due to increased production, and allowed them to take over the lands of their poorer farmer neighbors. The poorer farmers frequently had to go into debt to buy the new seeds and chemicals, which they were unable to repay because of falling commodity prices. They therefore had to sell their land. Better-off farmers might conceivably then employ the newly landless farmers on their expanded farms, but generally they did not, preferring to buy farm machinery instead, (15) sending the newly destitute off to the cities in search of employment. For the better-off farmers, this situation continued favorably for some years, but more recently problems of reduced yields (reduced soil fertility following several years of chemical fertilizer use), pest and disease problems related to weakening plant health due to reduced soil fertility, and human health problems concerned with agricultural chemicals. The need to continue on the proprietary seed and chemical treadmill (increasing cash inputs to crops) despite falling yields has been responsible for a general farmer impoverishment and indebtedness in many developing countries. Individual farmers and farming groups in south and southeast Asia have, over the last 10-15 years, made progress in escaping this vicious circle by converting to organic farming methods.
Figure 1: O/I Ratios for 25 Rice Systems a-h = pre-industrial, i-r = semi-industrial, s-y = fully industrial
Figure 2: Yield/labor comparisons for 25 rice-growing systems
Energy Inputs to Agriculture
Antony F.F. Boys (January 2005)
0. Introduction
The story of the use of fossil energy resources since the beginning of the Industrial Revolution over two hundred years ago is often told in terms of the development of our current modern, predominantly urban, lifestyles, characterized by the incredible scientific and technological progress of these two centuries. Not so often do we hear about how fossil energy resources, combined with scientific and technological progress, have changed the way we produce the food we need to survive. How much energy is being used in what form in agriculture? How has this come about historically, what does it mean, and where is it going in the mid-term future? This paper is an attempt to give a brief answer to these questions.
1. How fossil energy came to be used in agriculture
Energy, as we experience it in our lives, is a solar "gift". Life began on earth about 3.5 b yrs ago when certain chemical compounds became able to reproduce themselves through the ability to make direct use of incoming solar energy; autotrophs, which are able to produce their own energy through the direct use of solar energy. The development of the type of photosynthesis which releases oxygen, as in green plants today, occurred between 3 b and 2 b yrs ago.(1) Later in the evolutionary process, life forms not able to make direct use of solar energy (heterotrophs) emerged, and these were dependent for the energy for life on the autotrophs. They ate them. Thus emerges a picture of earth that existed up until the end of the last ice age, perhaps 15,000 years ago.
At that stage, mankind lived a "hunter-gatherer" existence. It is unsure when man became able to use fire (the conscious use of inanimate energy for cooking, defense and so on), but the archaeological record shows that fires were regularly used by about 40,000 yrs ago.(3) Agriculture, the conscious and organized use of plants and animals by mankind in an attempt to capture a larger fraction of solar energy income for human use, is thought to have begun around 10,000 yrs ago. This situation remains largely unchanged (a certain amount of technological innovation taking place in agriculture in the meantime – rice cultivation, the introduction of farming rotations, and so on) until about the middle of the 19th century when the work of chemists such as Justus von Liebig (4) resulted in the possibility of using inorganic chemicals as fertilizers. The industrial revolution also brought together the use of coal and machinery in the invention of the steam engine, which later found many applications as labor-saving technology in farming. In the 1840s, Rothamsted (UK) experiments showed that applications of nitrogen fertilizers offered the best path to higher grain crop yields, but it was not until 1887 that symbiotic nitrogen fixation in legumes was discovered. The big problem for agricultural progress at the end of the 19th century was that the ability to fix nitrogen by artificial means had not yet been invented.(5) The world currently has about 1.5 Gha of farmland under production.(6) and there is little room for expansion of this without the destruction of forests, wetlands and so on, or moving into inferior farmlands. Around 235 Mha of new farmland, mostly for wheat production, was created as the grasslands of North and South America, Australia, and Russia were brought under cultivation between 1850 and 1920. Yields were still low – about 1.5 ton/ha in the best European farming – but the population was rising, and the newly urban population was also beginning to consume more animal-derived foods – meat and dairy products. The land horizon was beginning to come into view, and it was recognized that only way to feed the growing population with its increasingly urban diet was to intensify the agricultural production of food on more or less existing farmland. Thus, William Crookes was led to proclaim in September 1898 that, "The fixation of nitrogen is vital to the progress of civilized humanity." (7)
Note on fossil fuel formation: Thecoal, formed from layers of plantremains generally in the CarboniferousPeriod 345-280 m yrs ago, and oil andnatural gas, believed to have beenformed from sediments of microscopicplanktons, or diatoms, mostly in theJurassic and Cretaceous Periods,190-65 m yrs ago, that we use as ourmajor energy sources now, has itsenergetic origin in solar radiation, asdoes all life.(2)
Note on population: Although increases anddecreases in (the rate of growth of) humanpopulations is a complex matter involving manysocio-economic factors, the basic physiologicalfactor involved, all other factors being equal – nonatural or man-made disasters, for instance – mustbe the relative availability of food. That the humanpopulation of the world has risen from 1 billionearly in the 19th century to over 6 billion at thebeginning of the 21st century must be due in nosmall part to the ability of man to appropriate alarger share of incoming solar energy through theapplication (as machinery or chemicals) ofinanimate energy forms, primarily fossil energy. Crookes did not have very long to wait. Fritz Haber (1868-1934) began work on ammonia synthesis from hydrogen and nitrogen (N2 + 3H2 ↔ 2NH3) in the summer of 1904. Success came on July 2, 1909 in an experiment which indicated ammonia yields of about 10% at 10 Mpa (10 million pascals – about 100 atmospheres) and 500oC. This was carried out with an experimental converter, a pressurized tube 75 cm tall and 13 cm in diameter, in Haber's experimental laboratory.(8) This apparatus was upgraded into a pilot plant device by Carl Bosch (1874-1940). Bosch's work was carried out so quickly that planning for a commercial plant of 10 t NH3/day began in April 1911, but was upgraded to 30 t NH3/day in November 1911. Construction at Oppau began May 7 1912, and was completed on September 9, 1913 (the day of first NH3 production). NH3 was converted to ammonium sulphate for fertilizer. However, war broke out on August 4, 1914, and NH3 production was redirected to the production of nitric acid for war munitions. A new and very large ammonia plant, built at Leuna, was completed in April 1917. This represented the completion of "preparations" for supplying the world with artificial nitrogen fertilizers, but these did not become the dominant means of supplying fixed nitrogen for agriculture till the 1930s, rapid increase in their use coming in the 1950s and onwards.(9) The next step in the food and energy story is the introduction of hybrid (high yielding varieties – HYV) varieties of the main staple grains, maize, wheat, and rice. The first commercial hybrid maize was introduced in the US in 1929. The higher yields of the new varieties of maize made it possible to increase land productivity. By the end of WWII, hybrid maize had replaced traditional varieties. In itself, this does not increase energy consumption, but besides the fact that the farmers must buy new seed each year, hybrid maize introduced an array of corollary farm products such as fertilizer, insecticides, herbicides, and other pesticides; the equipment used to apply these chemicals; and the enormous and enormously expensive machinery used to harvest maize. The higher yield of the hybrids had the overall effect of sustaining chronic overproduction, thus forcing farm prices down as cash inputs increased, contributing to the degeneration of soil quality, and helping to sustain human population increase through the increased availability of cheap food. In other words, by the 1930s the "modernization" (industrialization, mechanization and chemicalization – energy intensification) of agriculture in the US was basically complete with respect to maize, and this would soon spread to other advanced nations and other important crops. However, disease epidemics began to appear in US maize in the 1970s due to genetic similarity of maize crops grown over vast areas, and due to the decline in disease resistance of the plants resulting from the deterioration of the soil after several decades of chemical fertilizer use. This has stimulated the increasing use of toxic pesticides, and the race against nature to develop disease- and pest-resistant varieties, resulting in the development recently of genetically modified crops.(10)
2. The Green Revolution
In 1944, Norman Borlaug arrived at the International Center for the Improvement of Maize and Wheat (CIMMYT) near Mexico City. He was working on HYV wheat, but breeders found that the varieties that would produce increased yields when supplied with increasing amounts of nitrogen fertilizer caused the wheat plants to "lodge", limiting both the amount of nitrogen that could be used and the resulting yields. To solve this problem Borlaug experimented with Norin 10 (originating in Japan as a cross between a Japanese variety called Daruma, and an American wheat variety called Fultz), a Japanese "dwarf" variety. He incorporated the "dwarfing gene" from Norin 10 into the Mexican wheat varieties he was studying. The result was a shorter wheat that could withstand far greater fertilizer applications without lodging. The new wheats were 20 to 40 inches tall, compared to 50 to 60 inches for traditional varieties. They had stronger stems and roots, more flowering heads, and more grains per head – larger harvesting index. This was the beginning of the Green Revolution (GR).(11).
The process was soon repeated with rice at the IRRI in the Philippines. A dwarf variety of rice, IR8, was introduced to Asian farmers in 1966 and immediately boosted rice yields and harvests. However, IR8 quickly proved to be susceptible to a variety of pests and diseases and was followed in succeeding years by IR20, IR36, IR60, IR62, and IR64 in order to stay ahead of the pests and diseases. The result of the GR however was the "modernization" (industrialization, mechanization and chemicalization – energy intensification) of agriculture in much of the rest of the world, the developing countries. As the GR package requires fertilizers, irrigation, pesticides, and inevitably leads to the use of machinery.(12)
From the end of WWII until about the mid-1980s, the introduction of high-yield crops and energy intensive agriculture (the GR) led to increased crop production. World grain output expanded by a factor of 2.6 in this period, while the world population doubled from 2.5 to 5 billion. The success of the Green Revolution lay primarily in its increased use of fossil energy for fertilizers, pesticides, and irrigation to raise crops as well as in improved seed. It greatly increased the energy-intensiveness of agricultural production, in some cases by 100 fold
or more.(13) Large grain yield increases resulted in a massive improvement in land productivity. A secondary effect was that large areas of cropland could be continuously monocropped, eliminating the need for traditional rotation systems. Farm machinery was widely introduced, thereby raising labor productivity at the expense of use of more fossil fuels.
However, the GR engendered several problems, briefly:
- - reduction of biodiversity as HYVs replaced traditional crop varieties,
- - destruction of soil fertility through the heavy use of chemical fertilizers,
- - increase in nutritional imbalances due to monocropping and abandoning of rotational practices,
- - chemical contamination and pollution with the resultant effects on the environment and human health (14)
An important social consequence of the GR was that it often did not directly help to relieve poverty, as it was anticipated that it would. In general, the GR benefited the better-off farmers who could afford the whole GR package of seeds and chemicals and who had access to better quality and irrigated land, and preferential access to finance and credit. Increased harvests increased the incomes of these farmers, despite falling prices due to increased production, and allowed them to take over the lands of their poorer farmer neighbors. The poorer farmers frequently had to go into debt to buy the new seeds and chemicals, which they were unable to repay because of falling commodity prices. They therefore had to sell their land. Better-off farmers might conceivably then employ the newly landless farmers on their expanded farms, but generally they did not, preferring to buy farm machinery instead, (15) sending the newly destitute off to the cities in search of employment. For the better-off farmers, this situation continued favorably for some years, but more recently problems of reduced yields (reduced soil fertility following several years of chemical fertilizer use), pest and disease problems related to weakening plant health due to reduced soil fertility, and human health problems concerned with agricultural chemicals. The need to continue on the proprietary seed and chemical treadmill (increasing cash inputs to crops) despite falling yields has been responsible for a general farmer impoverishment and indebtedness in many developing countries. Individual farmers and farming groups in south and southeast Asia have, over the last 10-15 years, made progress in escaping this vicious circle by converting to organic farming methods.
Figure 1: O/I Ratios for 25 Rice Systems a-h = pre-industrial, i-r = semi-industrial, s-y = fully industrial
Figure 2: Yield/labor comparisons for 25 rice-growing systems
Shiva (1991) gives a very interesting comparison of labor and energy inputs to 25 rice cultivation systems. What the data show is that energy output:input ratios fall as fossil energy inputs increase, despite the increase in yields when compared with traditional pre-industrial agriculture (Figure 1). However, the data suggest that very labor-intensive rice cultivation can also result in high yields. The data become even more interesting when plotted on a log-log scale of labor input against yield. (Figure 2) The plots suggest that there are two developmental "directions" that rice cultivation could follow towards higher yields; the modern, industrial, direction or the direction of pre-industrial, labor- and organic intensification of the GR termed "involution" by Geertz.(16) Note that the yields shown as triangles in top right of Figure 2 are so high that it is possible they are for double-cropped rice. The yield figures have therefore been simply divided in two and plotted separately (as "×" – these values have been used to plot the points for f, g, and h in Figure 1) and show no large quantitative differenc