In this article we will discuss about the technological development in agriculture.
Scientists often breed improved varieties to fit other production-enhancing inputs. For example, after scientists introduced hybrid maize in the United States in the 1930s and nitrogen fertilizers became widely available, agronomists bred maize to respond to nitrogen fertilizers.
After the invention of the automatic tomato harvester, tomatoes were bred to withstand the rougher handling to which such machines subject these fruit. These technological advances have led to a style of agriculture that depends on purchased inputs. A survey of U.S. production methods for maize from 1910 to the present clearly shows this dependence.
The technological advances resulted from government sponsored and industrial research, the main thrust of which has always been to develop technological inputs that let farmers minimise per unit production costs. Many of these advances diminished work opportunities on the farm in favour of jobs in towns and cities where the inputs are manufactured.
The benefits of the lower production costs (cheaper food) accrued to the consumers and to agribusiness, whereas society as a whole had to bear the penalties (pollution and land degradation). Applying science and technology to crop production in developing countries between 1955 and 1985 resulted in the “Green Revolution.”
Worldwide food production has been rising by 2.3% annually as a result of the development of high-input agriculture, which in turn results from applying agricultural research and technology. This use of scientific knowledge started about 150 years ago in the developed countries and has resulted in yields taking off spectacularly, as can be charted quite accurately for individual crops.
Japan is a classic case of a country turning to high-yield agriculture. By 1900, this island nation was growing crops, mostly rice, on all its arable lands. But the population was still growing.
The government was reluctant to become dependent on foreign food imports lest a hostile nation cut off food from Japan during an international crisis. Short of lowering the people’s nutritional standard, the only thing to do was to increase the yield of the rice crop. The government mobilised the country’s political, social, and scientific resources, and as a result the yield per hectare tripled between 1900 and 1965.
One characteristic of the new crop varieties that raised Japanese rice yields and U.S. wheat yields was that they were short-stemmed and responsive to nitrogen fertilizer. But as with most varieties, scientists had selected and then bred them specifically to grow in the soils and climate of developed regions.
A variety that thrived in the U.S. Northwest had the genetic makeup to do well there, but not necessarily in the drier, hotter regions of the less developed world. There, crop production still relied on local varieties.
The genetically improved varieties of wheat and rice that drove the Green Revolution resulted from a targeted crop improvement program at two CGIAR institutes: the International Rice Research Institute (IRRI) in the Philippines and the International Centre for the Improvement of Maize and Wheat (CIMMYT) near Mexico City.
Farmers adopted the new varieties over a period of about 10 years, repeating a phenomenon that had occurred in the United States some 30 years earlier, when farmers adopted hybrid maize.
In the case of high-yielding varieties of wheat and rice, the farmers had to adopt not only the new seeds, but an entire technology package, including fertilizers, insecticides, weed killers, equipment for irrigation, and tractors to till the land.
Indeed, the new varieties let farmers grow two or even three crops per year, potentially increasing the demand for labour. Thus labour-saving technologies (tractors and herbicides) had to accompany the new strains. Furthermore, farmers needed nitrogen fertilizer so the new varieties would yield up to their potential (without fertilizer, they produced the same yields or less, than the landraces they replaced).
Adopting these new varieties of wheat doubled and tripled production in Mexico, India, and other countries in Asia.
Rice production increased similarly. But the yield increases on farms were never as great as those at research stations. Scientists at IRRI showed that the new varieties could out produce the old ones by a factor of 3 or 4, yet most farmers in Asia realized increases of only 1.5. This discrepancy in production is not surprising and also occurs in developed countries, where farms seldom match yields obtained in experiment stations.
Surveys of farmers who were using the new technology showed that the constraints on higher productivity were poor water control, inadequate nitrogen fertilizers, and diseases. Put another way, the major constraint was inadequate capital to purchase the input package needed to obtain the high productivity of which the seeds are capable.
The fundamental fact of the Green Revolution is that the farmers must manipulate the environment to get the most out of the plants, and too often they have not been able to afford it. Nevertheless, the Green Revolution allowed many developing countries to raise food production and even become food exporters.
International agricultural experts saw breeding the high-yielding varieties and applying the industrial inputs as the quickest way to increase production. As a result, agriculture in developing countries came to resemble agriculture in developed countries: more heavily dependent on purchased outside inputs, more capital intensive, and less dependent on labour.
Merely raising production is not enough to eliminate hunger. Because the need for farm labourers decreases as agriculture becomes more technological, the displaced labourers must find other employment. When farmers first apply a new technology for example, fertilizer or pest control-yield immediately increases as the amount of input rises. A little bit is good, and more seems better!
During this phase, the money spent on the technology results in a substantial return. Once the plant’s inherent capacity to respond to the input is reached, however, the yield increase slows drastically.
Adding fertilizer and other inputs follows the law of diminishing returns: less output for a given amount of input. In the United States, farmers now apply 90-100 kg of fertilizer per ha of cropland, and it is not easy to raise the yield further by adding more.
This figure is 65 kg/ Ha for India, so there is still hope for improvement, but fertilizer use is only 4 kg/ Ha in Ethiopia and 12 kg/Ha for Costa Rica. Gains in crop productivity should be possible in these countries if researchers can find the proper cropping systems and crop varieties that can take advantage of additional fertilizer.
When all technologies are maximal, agriculture may reach a yield plateau. Some crop physiologists argue that people will always be able to find new crop varieties to escape the yield plateau and take advantage of new and existing technologies.
Biotechnology has the potential to allow continual crop production increases. For example, scientists at IRRI and elsewhere are now producing hybrid rice varieties to raise rice yields even further.
The CGIAR institutes are catalysts for agricultural research in developing countries. The success of the Green Revolution, and the perceived need for more research on tropical and subtropical food crops, led to the establishment of other research institutes in different countries of the developing World.
These institutes have a triple mandate:
(1) To improve the crops assigned to them,
(2) To study farming systems for these crops, and
(3) To create gene banks in which the landraces of the crops under study can be preserved.
Initially the institutes focused on the approach that was successful with high yielding wheat and rice varieties in the 1960s and 1970s. That is, they concentrated on monoculture and on improving crop production by a package of improved varieties and associated technologies to modify the environment.
More recently, this focus has begun to change, showing a greater concern for integrating agriculture more with the natural environment. For example, scientists at ICRISAT in India have identified strains of groundnut that produce more than 1,000 kg grain per hectare, even when stressed by drought, compared to the 500-800 kg per hectare the normal varieties produce.
Similarly, they have found strains of sorghum that produce two to three times more grain than the present commercial types. One of their goals is to select drought-resistant crop plants to use not only in Asia, but also in the Sahel region of Africa. Scientists at CIAT in Colombia have identified genes in wild varieties of beans that let them resist attack by bruchid beetles.
These beetles do enormous damage to the seeds after harvest because they multiply in the dry, stored beans. By crossing a wild bean variety with a cultivated variety, CIAT scientists were able to introduce the bruchid-resistance genes into the cultivated variety.
When the CGIAR system of research institutes was first established, people saw biological and technological research problems as separable from political and social issues. The research institutes generated the necessary innovations and offered these as packages to various national and regional extension services or development authorities.
Fine tuning these packages to local conditions, and solving social and political problems that resulted from implementing new technologies, were the responsibilities of the implementing agencies or the governments of the countries in question.
In this system, people saw agricultural development as an activity that came from the top (the CGIAR institutes) and trickled down to the bottom (the farmers). This approach has worked reasonably well in some countries or areas, and poorly in others.
Agricultural development has not often been a high priority for many governments of developing nations, except for developing cash crops that earn foreign exchange. In many African countries, national agricultural research efforts have been weak, in part because governments mistakenly assumed the CGIAR institutes would solve all their agricultural problems, and also because these high-profile institutes attracted all the international funds and the best scientists.
The Green Revolution has done more than raise overall food production. It has also caused the rapid disappearance of the landraces and of indigenous farming systems that may have had much to offer to agricultural researchers. The top-down approach of development implies that agricultural researchers can learn little of value from subsistence farmers.
For example, although the institutes have often stressed monoculture, many farmers have been growing more than one crop on the land (either by crop rotation or by intercropping) for centuries. These practices led to a more sustainable agricultural system than did monoculture.
Scientists at the CGIAR institutes know they must do more than create new strains to hand over to extension agents. They need to become involved in understanding the tropical agro-ecosystems at the farm level and to evaluate with the farmers the local varieties (genotypes) and breed varieties for different environments.
Biotechnology is an important tool, but only one of many, to raise crop productivity in the less developed countries. Biotechnology will contribute to the continued rise of crop yields in the 21st century. Between 1960 and 1985 the yield of the major cereals (wheat and rice) rose dramatically in many developing countries, resulting in a 25% rise in the per capita food availability.
However, in more recent years this trend has levelled off. But two relatively new factors have arisen to challenge crop producers. First, increased demand for feed grains has followed increased demand for meat. Second, people realise that high-input agriculture can degrade the environment, so that plants must be even better adapted to the natural system.
Although people still need ever better genetically improved varieties in combination with new technologies, they also need to more thoroughly understand the sustainability of crop production.
Researchers need to devise different strategies for the highly productive regions that are already intensely cropped and where yields have risen dramatically and for the more marginal soils where, as in sub-Saharan Africa, productivity has stagnated and per capita food availability has declined.
Classical plant breeding has been a very important factor in the past successes. A new set of tools has become available in the past 20 years, that combined with plant breeding will allow people to produce the genetically improved varieties of the future.
This set of tools, which comes under the general title of biotechnology, encompasses a variety of laboratory methods that include:
1. Cell, tissue, and embryo culture.
2. Clonal propagation of disease-free plants
3. Identification of chromosome regions that carry important multi-genic traits
4. Gene identification and isolation
5. Genetic engineering for agronomic traits such as pest and disease resistance or better adaptation to environmental stresses
6. Genetic engineering for greater nutritive value
7. Genetic engineering to reduce postharvest losses
8. Genetically engineered male sterility to facilitate hybrid seed production.
The horticulture industry routinely uses meristem culture and plant regeneration from small parts of the meristem to propagate virus-free planting materials. The discoveries that the genetic material (DNA) of all organisms basically has the same structure and that genes from one organism can function normally after transfer to another organism have opened up the field of genetic engineering.
In plants, gene transfer is made possible by a natural process discovered in a soil-dwelling plant pathogen that transfers a few of its genes to plant cells. Molecular plant biologists have manipulated this process so that the pathogen will transfer one or more genes of the scientist’s choosing. This technique opens up unlimited possibilities for modifying crop traits.
Plant breeders were previously limited to using the genes of the crop’s closest relatives, but with genetic engineering they can now use any gene from any organism. It is important to emphasise repeatedly that the genetic engineering and biotechnology can make important contributions but are not the silver bullet that will solve all food production problems. It is but one of the many technologies that people need.
Genetically engineered plants that resist certain insect pests or can tolerate herbicides so that farmers can destroy weeds more efficiently, are being grown in more than half a dozen countries already (Argentina, Australia, Canada, China, India, Mexico, and the United States).
The rapid adoption of these new varieties has pleased the biotechnology companies that produce them and the farmers who adopt them because it lowers their production costs, but has aroused some anxiety in the general public.
Some countries in Western Europe and a few localities in the United States have banned genetically engineered (or manipulated, GM) crops. The four major GM crops being grown are rapeseed (canola), cotton, maize, and soybean. Molecular techniques will also greatly facilitate chromosome mapping of important agronomic traits.
This will make it easier to follow these traits in the progeny of crosses when the traits have no easily discernible phenotype (characteristic) in the field. It will also greatly speed up classical breeding, which is a rather slow and cumbersome process.
Gene replacement (gene therapy) is not yet a reality, but is on the drawing board. It eventually will be possible to take a small chromosomal region that encompasses a whole set of genes, and simply replace it with another region from a plant that is more distantly related.
The effects of intensive agriculture on the ecosystems are causing concern about its sustainability. Growing populations and increasing affluence demand ever- increased output from agricultural systems.
This is true whether we are talking about the high-input agriculture of the United States and Western Europe, about nomadic herds in Africa, or about intensive rice cultivation in Asia. Concerns are now being raised about the sustainability of this ever intensifying productivity.
The World Commission on Environment and Development defined sustainable development as “development which meets the needs of the present without compromising the ability of future generations to meet their own needs.” To understand sustainability, we must first look at the rate at which people are losing productive soils as a result of present agricultural practices.
The FAO of the United Nations has estimated that salinization, soil erosion, and desertification have degraded a quarter of the world’s arable land. Second, there may not be enough energy resources to maintain high-input agriculture. Third, the increasing use of pesticides is arousing concern that people are polluting ecosystems with synthetic chemicals.
Fourth, the trend toward genetically uniform crops increases the potential for serious disasters by eliminating the many different strains of a given crop that farmers previously used. Fifth, government policies perpetuate conventional agriculture and discourage farming practices that could make agriculture more sustainable.
The term land degradation denotes the physical and chemical changes that reduce long-term soil productivity. Such changes are sometimes very obvious but are often difficult to measure because they occur over long periods of time.
Other improvements, such as more fertilizer or new genetic strains, often compensated for them, so the effects of land degradation do not always show up as decreased yield-at least, not in the short run.
Physical degradation takes the form of erosion, the carrying away of soil particles by wind and water. In an annual cropping system, the soil is alternately covered with plants, and then almost totally bare. When the soil is bare, it is exposed to higher wind velocities and to the force of raindrops, which destroy the structure of the uppermost layer of topsoil. The net result is muddy runoff and/or dust storms.
Chemical degradation can take several forms, including:
(1) Acidification from acid rain,
(2) Alkalinisation and salinization (build-up of salts) as a result of irrigation or the intrusion of saline groundwater into topsoil,
(3) Exhaustion of mineral nutrients when farmers don’t use enough fertilizer to replace minerals removed with the crop, and
(4) Leaching of excess mineral fertilizers into streams, lakes, and groundwater. Pesticides and Herbicides.
Agriculture uses pesticides and herbicides extensively in the developed countries, and their use in developing countries has also increased rapidly. Many problems accompany their use, including the emergence of pesticide-resistant pests, adverse health effects on farm workers, pesticide residues on crops, and pollution of lakes, streams, and groundwater with pesticides and herbicides.
Furthermore, the realisation that pesticides have not diminished the proportion of the crop lost to pests is prompting many people to try alternate pest control methods. There is renewed emphasis on pest-resistant varieties and biological pest control.