Plant Breeding and Yields

An inquiry into agriculture from the political ecological viewpoint focuses on how and why people modify and harvest ecosystems to obtain their needs, and create political economic structures to control the production and distribution of the ecosystem's productivity or yield. For most of human history, yield was always valuable and only occasionally became large enough to be considered excessive. (Generally the periods of surplus have been confined to the nineteenth and twentieth centuries.) One chronic political ecological problem to solve, therefore, was how to increase yields from the biosphere.

People who till the soil have known for millennia of two fundamentally different ways to increase the yield of the harvest. The first method is to increase the amount of land under cultivation, and the second is to increase the yield per area of land. Either way, the total yield goes up. Expansion of cultivated area was the most important way of increasing the harvest until about 1900. To be sure, history can point to a few instances in which new methods increased yields per hectare before that time. Nevertheless, from the beginning of agriculture some 10,000 years ago until 1900, the primary method of increasing the total yield was to increase the amount of land tilled.

A change of enormous importance happened in the years after 1900: farmers guided by science learned how to make each hectare of land yield more. Traces of this yield transformation were visible in the eighteenth century and before, but the most dramatic increases in yield per hectare came after 1945. Particular spots in Europe, Japan, and North America were the first locations of the transformation in yields, but ultimately the knowledge on which it was based spread to many other countries. By 1980, efforts were under way to make the knowledge available to every part of the world.

This revolution in yields was intimately connected to the factors determining land control. An individual who could successfully use the higher yielding practices was in a better position to amass wealth, with which acquisition of land might be possible. Reciprocally, control of land use was essential to using the new science-based production technologies.

The yield transformation was also one of the factors that influenced the political and military strength of nation-states. Cultures that first learned how to obtain higher yields were in a better position to control areas of land. It is thus perhaps not a coincidence that the yield-enhancing practices developed in Europe after the eighteenth century partially enabled the spread of European imperialism in the nineteenth and twentieth centuries.

New scientific and technological knowledge lay behind the transformation of yields. What were the sources of the new science and technology? Why were these new practices developed? What effects did the initial successes with yield enhancement have on subsequent efforts to increase yield yet again?

Important new technological practices in eighteenth-century Europe, spawned largely by gentlemen and farmers, were the proximate roots of the yield-enhancing practices of the twentieth century. These were the days before professional cadres of scientists, but by the early 1900s development of new agricultural technologies was largely in the province of organized, institutionally supported professionals.

A key factor in the coalescence of professional science was the close relationships among (1) the desire to develop better agricultural science, (2) the ability of a society to support a cadre of scientists, and (3) the power to allocate resources toward the research enterprise. Essentially a positive feedback loop developed in which higher yields translated into more wealth, which in turn prompted landowners and others to desire yet higher yields. The new wealth from the previous successes in turn provided the potential to support yet further research and development, and those who controlled this wealth had the power to direct its allocation to research. New practices produced a new wave of yield enhancement, which ignited the cycle again.

Plant breeders were the key people in the yield transformation because they selected the plant varieties that were genetically able to produce higher yields. Individuals from other sciences were also involved, particularly soil scientists, fertilizer chemists, hydrologists and irrigation specialists, entomologists and plant pathologists, and statisticians. Nevertheless, it was the plant breeders who more than anyone else created the conditions for the yield transformation, and it is primarily their story that needs to be understood.

What is so remarkable about the plant breeders is that they are essentially unknown by the general public. Yet plant breeders have been responsible for a radical revolution in human ecology. Larger yields after the eighteenth century increasingly enabled a higher proportion of people to forgo agricultural labor and turn to the emerging factories for work. Increased numbers of people working in factories ultimately meant a redistribution of people from the rural to the urban areas. In a very direct way, therefore, the development of higher yields must be seen as a component of the industrial revolution and the general process of urbanization, which became global in the second half of the twentieth century.

In fact, it is possible to think of increased agricultural yields, particularly of cereals, as an ability to form capital —an accumulation of goods devoted to the production of other goods. An increase in cereal yields, if it is beyond the needs of the producers for their own subsistence, can be accumulated and used to support human labor to make something besides more cereal grain. Therefore, the owner of surplus cereal grain can turn the surplus into capital and thus promote the production of many other types of goods and services.

Another way to look at the revolutionary implications of yield-enhancing technologies is to imagine life without them. First, on a dietary level, smaller supplies of cereals would mean more expensive staples and livestock products. In addition, industrial uses of grains would be less common. Lower yields would also mean that more land had to be cultivated to get the same yield. It is possible, therefore, that the earth would not now be supporting close to 6 billion people, that is, the population growth of the last 300 years would have leveled off. Finally, the need to cultivate more land, combined with fewer people working in industry, would probably mean that farmwork would be less mechanized. As a result of less mechanization, more labor would be needed in rural areas, and fewer people would live in cities. In total, the lives of each of us probably would be very different had these yield-enhancing techniques not been developed.

It is a more complex question to ask whether people would be better off without the yield-enhancing practices. What is simple to say is that our relationships with nature and with each other would be greatly different. Technologies that enhanced yields changed human political ecology, possibly forever.

Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

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