Introduction to agricultural systems

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Economic Environment - What is different?

1.Markets - self sufficiency in Brazil versus export economy in Saskatchewan



2.Industry - Processing, Input levels (fertilizer, machinery, pesticides), transportation system, general infrastructure

3. Labour - wealth distribution, government


The differences in physical, social and economic environments have created two vastly different agricultural systems.
3.7 Assessment of agricultural systems (Conway, 1987, p.100; Reading 12. Pretty, 1995).

Which of the two systems, cassava production in Brazil or grain production in Saskatchewan are more successful? How can and should agricultural systems be assessed? These questions are difficult to answer, because how they are assessed may depend on what valued, which will vary among cultures and people. Are profits the most important goal, or is it maintaining a healthy environment, ensuring a safe and stable food supply for the family, or feeding the world? Some of the most common ways of assessing agriculture are described in the next section.

3.7.1 Productivity

Productivity refers to the output of valued product per unit of resource input. Common measures of productivity are yield or income per hectare, or total production of goods and services per household or per nation. Yield may be in kg of grain, tubers, leaves, meat or fish, in calories, proteins or vitamins, or in monetary value at the market. Yield measured as output per unit area can provide different information than yield per unit of inputs. For example, low yields per unit area can be quite high per unit of input - which is the better measure? Some researchers suggest that yield should be measured as the relative efficiency with which energy is stored or assimilated (Bawden and Ison, 1992, p. 21).

There are three basic inputs into agriculture: land (includes solar energy); labour (human energy - people); and, capital (includes fossil fuel energy). The yield that will result from various levels of these inputs depends on the quality of the land or ecosystem (climate, soil, natural vegetation) and amount of inputs (labour, capital including energy subsidies).


Should agricultural systems be assessed on the basis of productivity? Success in agriculture is usually measured in terms of production attained or quantity of food produced, and by the economic efficiency of farming and food processing. The effect on soil and water resources has received some study, but the sociological effects of increasingly larger and more efficient farms has generally been ignored.

Intensive production systems in regions with high production potential, such as Western Europe, now have government programs to reduce chemical inputs, especially pesticides and N fertilizer, primarily because of water pollution problems. These governments are realizing that intensive, high input, high yielding agriculture may not be sustainable over the long-term without attention to actual and potential environmental problems.


3.7.2 Stability and Risk

Stability refers to constancy of productivity, despite small disturbances resulting from the normal fluctuations and cycles in the environment. Fluctuations can include changes in climate or in the market demand for agricultural products. Natural systems are inherently stable. They have evolved over a long time, so are adapted to the climate and biophysical conditions of a region, and they are diverse with complex relationships of energy transfer (etc.) that are difficult to destabilize with normal environmental fluctuations.

The stability of agricultural systems depends on their diversity and ability to respond to change. Factors that influence that ability are cropping mix (monoculture versus mixed cropping) and crop adapted-ness to environment. The most stable agricultural systems are those that tend to mimic the natural system, such as ranching in southwestern Saskatchewan, which is a more environmentally stable system of agriculture than the production of annual crops in that region.

3.7.3 Sustainability

The sustainability of an agricultural system reflects its ability to maintain productivity when subject to:



  1. a major disturbing force, an infrequent large and unpredictable disturbing force which has the potential of creating an immediate, or a large disturbance or perturbation, such as rare droughts or floods, a new pest, or a sudden rise in an input price, and

  2. a stress, or a continuous, relatively small predictable disturbing force which has a large cumulative effect, such as soil salinity, toxicity, erosion, indebtedness, or declining market demand.

Sustainability determines the persistence or durability of an agricultural system=s productivity under known conditions. It implies the use of human inputs since agriculture is a human-managed system (Figure 3-12 from Tivy, 1990, p.3). Examples are subsidies, usually in the form of fertilizer to counter the effect of repeated harvest, or fossil fuels to power machinery, and control agents, such as pesticides or tillage for weed control. Inputs may become part of a problem (i.e., pesticide resistance).

Different people have different ideas about what sustainability means - there are three major views (Bawden and Ison, 1992, p. 23):



  1. Food sufficiency view: The main goal of agricultural systems is to feed the world. Preservation of the resource base or cultural values of agriculture is of secondary importance;
  2. Ecological view: An agricultural system that depletes, pollutes or disrupts the ecological balances of the natural system is unsustainable and should be replaced with one that honours that long-term biophysical constraints of nature. Technology that increases productivity but degrades the environment should not be used; and,


  3. Social and cultural view: The relationship between people and their environment is important. This is a people centred approach.

A sustainable agricultural system can supply the material (food and fibre), social and economic needs of people without damaging their resource base (biophysical environment) in the process. If the system is too environmentally damaging, it will not remain productive in the long-term. Examples: erosion, resistant pests, loss of soil fertility, climate change, accumulation of toxins in the soil.

We have already discussed the sustainability of natural systems and determined that they are inherently sustainable (i.e., barring catastrophe, they could continue indefinitely because nothing is used in excess of its rate of renewal and nothing is wasted). Unsustainability is a result of human actions. Sustainable agriculture systems must be environmentally sustainable in the same way that natural systems are sustainable, but they must also be economically and socially sustainable.

Time and sustainability. The sun is a dying star, so ultimately all processes dependent on the sun are not sustainable. However, the time period over which the sun is dying is so long it is not meaningful to discuss agricultural sustainability within that time frame. At the other extreme, seeds will germinate without being planted, but without sunlight, water, and nutrients their growth is not sustainable for more than a few days. This is too short for a time frame for meaningful debate about system sustainability.

Humans generally think in a short time frame, from a few years to generations. Decisions are often made to be effective for the life of a political term of a few years, and memory is hazy after a few years. The idea that we are currently acting in a way that is not sustainable way for the next several generations, by contributing to greenhouse warming, destroying the ozone layer or reducing soil quality is difficult to perceive and understand. It is even more difficult to control with because our institutions tend to work best at solving short-term problems. We forget that natural systems require decades or hundreds of years to develop and that our planning horizon should be at least that long.


Economic sustainability. For a farmer in a subsistence system, economic sustainability means that they produce enough food, fibre, shelter for the family with enough left over (i.e., seed, water buffalo etc) to be able to plant again the next year. For a farmer in a commercial system, they must earn enough profit to purchase the needs of the family and the inputs, equipment and labour required to plant again next year.

Are organic farms more sustainable than farms that use chemical inputs? Some farmers produce crops organically, i.e., although they do use fossil fuel inputs, they do not use chemical fertilizers and pesticides, thus avoiding some environmental problems. However, this system may be no more sustainable that conventional systems, because it is still export based. Nutrients from the soil are exported with the crop, and when nutrient export exceeds nutrient inputs, there is a net loss of nutrients from the soil, and the system is unsustainable.

Some organic farmers tighten nutrient cycles by recycling plant and animal wastes back onto soils, thereby reducing the export of nutrients from the farm and the need for off-site inputs. Use of green manure crops add organic matter and N, but nutrients such as P may become limiting unless added as fertilizer or manure.

Organic farms have reduced inputs costs, but also yields, compared to conventional farms. Economic sustainability is threatened if lower yields are not balanced by reduced inputs costs or higher crop prices. Thus, well managed organic farms can be environmentally sustainable, and desirable at the community level, but economically unsustainable at the individual farm level if commodity prices are low.

3.7.4 Equatability

Equatability refers to how evenly the productivity of the system is distributed among the human beneficiaries. Distribution of total production can be at the level of the field, the village or the nation. Human beneficiaries may be a farm household, members of the village, or a national population. This is the only one of the agricultural system properties that does not have a counterpart in natural systems.


3.7.5 What is the best system?

Sustainable agriculture may be a compromise between high-input and organic agriculture. It may require a shift from measuring success in terms of output or production, to efficient input management that focuses on the careful use of potentially environmentally damaging inputs. Diversification may increase system sustainability. Crop rotations that include forages increase soil organic matter, break crop disease cycles, control weeds. Mixed farms that include livestock make forage production beneficial, and allow better use of low quality soils that are not suitable for annual crop production; feeding hay and low quality grain from the farm on the farm, and using straw for bedding permits internal cycling of these materials on the farm. Diversified farms require more labour, and therefore employ more people on the farm.

In the Awheat monoculture@ on the Prairies, many farmers live in urban areas and commute to the farm during the growing season - they contribute little to the rural economy and reduce the social sustainability of rural areas. However, there are some factors that contribute to farmers= decisions to use a short and simple rotations. In semi-arid regions, on good quality agricultural land, large-scale production of one crop (wheat), with some additional annual crops, works well and is suited to the climate. The cost of production increases on farms that produce many plant and animal crops, especially equipment costs.
3.10 Reading: Food Resources (Miller, G.T. Jr., 1990. CHAPTER 11, pp. 273-302 in Resource Conservation and Management, Wadsworth Pub. Co., Belmont, California)

Hunger is a curious thing: At first it is with you all the time, working and sleeping and in your dreams, and your belly cries out insistently, and there is a gnawing and a pain as if your very vitals were being devoured, and you must stop it at any cost.... Then the pain is no longer sharp, but dull, and this too is with you always.


Kamala Markandaya
General Questions and Issues
1. What types of agricultural systems provide food from domesticated crops and livestock throughout the world?

2. What are the world's major food problems?

3. Can increasing crop yields and cultivating more land solve the world's major food problems?

4. What government policies can increase food production?

5. What can giving food aid and redistributing land to the poor do to help solve world food problems?

6. How can agricultural systems in MDCs and LDCs be designed to be ecologically and economically sustainable?

7. What are the pros and cons of using pesticides to help protect crops from damage and loss, and

what are the alternatives to using pesticides?



What uses more of the earth's land, water, soil, plant, animal, and energy resources and causes more pollution and environmental degrada­tion than any other human activity? Agriculture. Each day, the world has 247,000 more people to feed, clothe, and house. By 2020 the world's population is expected to reach at least 8 billion. To feed these people, we must produce as much food during the next 30 years as we have produced since the dawn of agriculture about 10,000 years ago.

Producing enough food to feed the world's pop­ulation, however, is only one of a number of complex, interrelated food resource problems. Another major problem is food qualityCeating food with enough proteins, vitamins, and minerals to avoid malnutri­tion. We must also have enough storage facilities to keep food from rotting or being eaten by pests after it is harvested. An adequate transportation and retail outlet system must be available to distribute and sell food throughout a country and the world.

Poverty is the leading cause of hunger and pre­mature death from lack of food quantity and quality. It is the main reason that one out of five people on earth today are not adequately fed. Making sure the poor have enough land or income to grow or buy enough food is the key to reducing deaths from mal­nutrition. Farmers must also have economic incen­tives to grow enough food to meet the world's needs. Finally, the world's agricultural systems must be man­aged to minimize the harmful environmental impacts of producing and distributing food.

3.10.1 World agricultural systems: how is food produced?

Plants and Animals That Feed the World Although about 80,000 species of plants throughout the world are edible, only about 30 crops feed the world. Four cropsCwheat, rice, corn, and potatoCmake up more of the world's total food production than all others combined.

The rest of the food people eat is mainly fish, meat, and animal products such as milk, eggs, and cheese. Most of these foods come from just nine groups of domesticated livestock: cattle, sheep, swine, chickens, turkeys, geese, ducks, goats, and water buffalo.

Meat and animal products are too expensive for most people, primarily because of the loss of usable energy when an animal trophic level is added to a food chain. Poor people can get more food energy per unit of money or labor from grain than from meat and animal products.

However, as incomes rise, people consume more grain indirectly, in the form of meat and products from grain-fed domesticated animals. In MDCs, almost half of of the world's annual grain production (especially corn and soybeans) is fed to livestock. Also about one-third of the world's annual fish catch is converted to fish meal and fed to livestock.


Major Types of Agriculture Two major types of agri­cultural systems are used to grow crops and raise live­stock throughout the world: industrialized agriculture and subsistence agriculture (see Spotlight). Industrialized agriculture produces large quantities of a single type of crop or livestock for sale within the country where it is grown and to other countries. This is done by supplementing solar energy with large amounts of energy from fossil fuels, mostly oil and natural gas. Industrialized agriculture is widely used in MDCs and since the mid-1960s has spread to parts of some LDCs. It is supplemented by plantation agriculture, in which specialized crops such as bananas, coffee, and cacao are grown in tropical LDCs primarily for sale to MDCs.


Traditional subsistence agriculture produces enough crops or livestock for survival and in good years to have some left over to sell or put aside for hard times. This is done by supplementing solar energy with energy from human labor and draft animals. The three major types of subsistence agriculture are shift­ing cultivation of small plots in tropical forests, intensive crop cultivation on relatively small plots of land in other areas, and nomadic herding of livestock. These forms of agriculture are practiced by about 2.6 billion peopleCone of every two persons on earthCwho live in rural villages in LDCs.

The relative inputs of land, human and animal labor, fossil fuel energy, and capital needed to produce one unit of food energy by various types of agriculture are shown in. It shows that industrialized agri­culture is capital and energy intensive, whereas inten­sive subsistence agriculture is labor intensive, and shifting cultivation and nomadic herding are land intensive. An average of 63% of the people in LDCs work in agriculture, compared to only 10% in MDCs.


Industrialized Agriculture and Green Revolutions Food production is increased either by cultivating more land or by getting higher yields from existing crop­land. Since 1950 most of the increase in world food production has come from increasing the yield per acre by what is called a green revolution. It involves planting monocultures of scientifically bred plant vari­eties and applying large amounts of inorganic fertil­izer, irrigation water, and pesticides.

Between 1950 and 1970 this approach led to dra­matic increases in yields of major crops in the United States and most other industrialized countries, a phe­nomenon sometimes known as the first green revolution. In 1967, after 30 years of genetic research arid trials, a modified version of the first green revo­lution began spreading to many LDCs. New high-yield, fast-growing dwarf varieties of rice and wheat, spe­cially bred for tropical and subtropical climates, were introduced into several LDCs in what is known as the second green revolution.

The shorter, stronger, and stiffer stalks of the new varieties allow them to support larger heads of grain without toppling over. With large inputs of fertilizer, water, and pesticides, wheat and rice yields of these new varieties can be two to five times those of traditional varieties. The fast-growing varieties allow farmers to grow two and even three consecutive crops a year (multiple cropping) on the same parcel of land.

Nearly 90% of the increase in world grain output in the 1960s and about 70% of that in the 1970s were the result of the second green revolution. In the 1980s and 1990s at least 80% of the additional production of grains is expected to be based on improved yields of existing cropland through the use of green revolution techniques.


These increases, however, depend heavily on fos­sil fuel inputs, principally oil. On average it now takes 1.2 barrels of oil to produce a ton of grain, twice the amount of oil used in 1960. Since 1950, agriculture's use of fossil fuels has increased sevenfold, the number of tractors has quadrupled, irrigated area has tripled, and fertilizer use has risen tenfold. Agriculture, like other parts of industrialized societies, has become addicted to oil, now using about one-twelfth of the world oil output.
SPOTLIGHT: Comparison of industrialized and subsistence agriculture

Industrial :Crop Production

Grow large quantities of food for sale by investing a large amount of money. usually borrowed

Buy scientifically bred hybrid seeds of a single crop variety and plant them as a monoculture on a large field.

Buy expensive equipment that is costly to operate, repair, or replace.

Often farm on flat, easily cultivated fields with fertile soil.

Increase crop yields by using irrigation and commercial inor­ganic fertilizers.

Plant one crop and use chemicals to kill pest species along with a variety of predators of pest species.


Work against nature by using large amounts of fossil fuel energy to keep a monoculture at an early stage of ecological succession.

Do most work with fossil-fuel-powered farm machinery

Meat and Animal Product Production

Produce large quantities of a single type of meat or animal product for sale by investing a large amount of money, usu­ally borrowed.


Use animal feedlots to raise hundreds to thousands of domesticated livestock in a small space. Give animals antibiotics and growth hormones to encourage rapid weight gain and to achieve efficient, factory-like production.

Produce fatty meat that most consumers like but is consid­ered unhealthful in large amounts.

Use massive inputs of energy by burning fossil fuels for heat­ing, cooling, pumping water, producing feed, and transport­ing supplies and livestock.

Produce large concentrations of animal wastes, which can wash into nearby surface water and contaminate it with disease-causing bacteria and excess plant nutrients (cultural eutrophication).

Subsistence: Crop Production

Grow enough food to feed their families investing little if any money

Plant a diversity of naturally available crop seeds on a small

Make or buy simple equipment that costs little to run, repair, or replace.

Often farm on easily erodible, hard to cultivate, mountainous highlands, drylands with fragile soils, and tropical forests with low-fertility soils.

Increase crop yields by making efficient use of natural inputs of water and organic fertilizers.

Plant a diversity of crops to provide numerous habitats for natural predators of pest species.

Work with nature by allowing a diversity of crops to undergo guided ecological succession.

Do most work by hand or with help from draft animals.

Meat and Animal Product Production

Produce enough meat and animal products to feed their fami­lies, investing little money.

Use natural rangeland, grassland, or forests and fields as sources of food and water for small groups of livestock. Often move flocks from one place to another to provide enough food and water.

Produce lean meat that is more healthful than fatty meat

Use human and animal labor with no inputs of fossil fuels

Return nutrient-rich animal wastes to the soil where animals roam, or collect it and use it as organic fertilizer for growing crops, or dry it and burn it as a fuel for heating and cooking.

the additional production of grains is expected to be based on improved yields of existing cropland through the use of green revolution techniques.


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