develop sustainable, term applied to the economic and social development that allows to make in front of the necessities of the present without putting in danger the capacity of future generations to satisfy their own necessities. There are two fundamental concepts in what refers to the use and sustainable administration of the natural resources of the planet. In the first place, the humanity's basic necessities should be satisfied, food, clothes, place where to live and I work. This implies to pay attention to the necessities, in unsatisfied great measure, of the poor of the world, since a world in which the poverty is endemic will always be inclined to the ecological catastrophes and of all type. In second place, the limits for the development are not absolute, but rather they come imposed by the technological level and of social organization, their impact about the resources of the environment and the capacity of the biosphere to absorb the effects of the human activity. It is possible to improve as much the technology as the social organization to open step to a new era of sensitive economic growth to the environmental necessities.
During the decades of 1970 and 1980 it began to be the natural resources more and more undoubtedly they were being wasted on behalf of the ' desarrollo'. accidental changes were taking place in the atmosphere, the floors, the waters, between the plants and the animals, and in the relationships among all them. It was necessary to recognize that the speed of the change was such that it overcame the scientific and institutional capacity for ralentizar or to invest the sense of its causes and effects. These big environmental problems include: 1) the global heating of the atmosphere (the effect hothouse), due to the emission, on the part of the industry and the agriculture, of gases (mainly dioxide of carbon, methane, nitrous oxide and chlorfluorocarbons) that absorb the radiation of long wave reflected by the surface of the Earth; 2) the exhaustion of the layer of ozone of the stratosphere, protective shield of the planet, for the action of chemical products based on the chlorine and the bromine that it allows a bigger ultraviolet penetration of rays until their surface; 3) the growing contamination of the water and the floors for those poured and discharges of industrial and agricultural residuals; 4) the exhaustion of the forest cover (deforestation), especially in the tropics, for the exploitation for firewood and the expansion of the agriculture; 5) the loss of species, so much wild as domesticated, of plants and animals for destruction of natural hábitats, the agricultural specialization and the growing pressure to the one that you/they are subjected the fisheries; 6) the degradation of the floor in the agricultural and natural hábitats, including the erosion, the encharcamiento and the salinización that she/he takes place with the time the loss of the productive capacity of the floor.
At the end of 1983, the general secretary of the United Nations requested to the first minister from Norway, Gro Harlem Brundtland that created an independent commission to examine these problems that he suggested mechanisms so that the growing population of the planet could make in front of her basic necessities. The group of ministers, scientists, diplomats and legislators celebrated public audiences in five continents during almost three years. The main task of the call Comisión Brundtland was to generate a calendar for the global change. Their command specified three objectives: to reexamine critical questions related with the environment and the development, and to formulate proposals realists to make them front; to propose new formulas of international cooperation in these topics able to guide the politics and the events toward the realization of necessary changes; and to increase the understanding levels and the individuals' commitment, the organizations of volunteers, the companies, the institutions and the governments. The report was presented before the General Assembly of the United Nations during the autumn of 1987.
In the report two futures are described: one viable and another that is not it. In the second, the human species continues draining the natural capital of the Earth. In the first one the governments adopt the concept of sustainable development and they organize new, more equal structures that begin to close the abyss that separates to the rich countries of the poor. This abyss, in what refers to the energy and the resources, is the main environmental problem of the planet; it is also their main development problem. In any event, what was clear was that the incorporation of economic and ecological considerations to the planning of the development would require an entire revolution in the taking of economic decisions.
After the Commission, the following significant international event was the Summit on the Earth, taken place in June of 1992 in River of Janeiro (sees you Summit of River). Denominated Conference of the United Nations on the environment and the Development, in her 178 governments, included 120 Bosses of State were represented. It was to find ways of translating the good intentions in concrete measures and that the governments signed specific agreements to make in front of the big environmental problems and of development. The results of the Summit include global conventions on the biodiversity and the climate, a Constitution of the Earth of basic principles, and an action program, called Calendar 21, to put into practice these principles.
The results were steamed up by the negative of some governments to accept the calendars and objectives for the change (for example for the reduction of gassy emissions that you/they lead to the global heating), to sign certain documents (there was who she/he said that the Agreement about the Biological Diversity weakened the industries of biotechnology of the industrialized countries), or to accept the adoption of having measured vinculantes (like in the case of the forest principles). In their 41 chapters, the contained action program in the Calendar 21 almost approaches all the topics related with the sustainable development that can imagine, but the sufficiently financed thing is not.
Nevertheless, the Summit was a momentous understanding exercise at the politics's higher levels. Starting from her, no excellent politician will be able to adduce ignorance of the existent bonds between the environment and the development. Also, she/he left clear that were necessary fundamental changes to reach a sustainable development. The poor should receive a fair participation in the resources to sustain the economic growth; the political systems should favor the civic participation in the taking of decisions, especially the relative ones to activities that affect to their lives; the rich ones should adopt lifestyles that are not left the mark of the ecological resources of the planet; and the size and the population's growth should be in harmony with the changing productive capacity of the ecosystem.
Ten years later, the Organization of the United Nations (UN) it summoned the Summit on Sustainable Development, also well-known as Río+10 to take place one decade after the first Summit of the Earth. The final agreements agreed in this Summit that gathered in the city surafricana from Johannesburgo to representatives of 191 countries, included a Political Declaration that formulates a series of principles to reach the sustainable development, and a Plan of Action in which you/they highlight the following commitments:
to) to reduce in half in 2015 the population that lives without drinkable water and without net of reparation of residual waters.
b) to recover, in the year 2015, the fishing reservations where it is possible and to create, before 2012, a net of protected marine areas. This plan contemplates the reduction of the captures to return at healthy levels the fishing caladeros.
c) to reduce, significantly, the biodiversity loss before 2010.
d) to minimize, before 2020, the impact taken place by the emission of chemical products to the environment.
However, the Summit of Johannesburgo disappointed to the non government organizations (ONGs) that waited concrete agreements in other aspects like the increase of the renewable energy sources or the fight against the poverty.
The agriculture has experienced many revolutions along the history from its appearance she/he makes between about 8.000 and 10.000 years until the renowned agricultural revolution, happened in Europe among the XVII and XIX centuries. Along the XX century the rural environment has suffered transformations in most of the world. The governments have incentivated the adoption of modern varieties for the crops and of modern races of livestock, together with external resources (as fertilizers, pesticidas, antibiotics, credit, machinery), necessary so that the first ones are productive. They have supported the creation of new infrastructures, like irrigation programs, highways and markets, and they have guaranteed the prices and the market for the agricultural production.
The process of agricultural modernization has produced three types different from agriculture: 1) the one industrialized, 2) the call green revolution and 3) all the other types: that of low external contribution, the traditional one and the not improved. The first two types have been able to respond before the technological resources, giving place to systems of high yield in the production of foods. They are endowed with access to highways, urban markets, ports and, to his inclination, to external contributions, machinery, commercialization infrastructures, transport, facilities of having processed agricultural and credit. They have good floors, an appropriate supply of water (well for a regular pluviosidad or by means of irrigation systems), access to modern varieties of cultivations and livestock races and to derived products of the petroleum and machinery.
In the countries of the Third World, these systems that demand big contributions of the exterior, are used in the big plains and irrigated deltas of the south, southeast and east of Asia, as well as in parts of Latin America and the África north, and in other isolated areas. They spread to be exploitations of monocultivos unique animal y/o, guided for sale, and they understand the irrigated cultivations of rice in the low lands, the wheat and the cotton; the plataneros plantations, pineapples, palm of oil and cane of sugar; the vegetables in the vicinity of the urban centers, and the intensive breeding of livestock and birds.
These are the lands of the call green revolution. The scientists developed new varieties of basic cereals, getting that they matured before, what allowed to pick up two crops to the year that you/they went insensitive to the duration of the day, what facilitated their cultivation in a great fan of latitudes, and that they produced a bigger grain proportion in connection with the straw. These modern varieties were given to the farmers together with contributions, or entrances, of high cost that you/they included inorganic fertilizers, pesticidas, machinery, credits and it dilutes. As a result, the half yield of the cereals has been duplicated in 30 years. Taking in consideration the population's growth in the same period, the improvement has been of 7% of the total of the foods taken place by person. This half value, nevertheless, hidden significant regional differences: in the Asian Southeast, the production per cápita of foods has increased near 30%, but in África 20 percent has descended. What is more, they are still about 1.000 million people in the world whose diet doesn't contribute enough calories to work, of those that 480 millions live in too poor homes to obtain the necessary energy for the appropriate growth of the children and to maintain a minimum activity on the part of the adults.
In the industrialized countries a similar revolution took place. The farmers were modernized, adopting the machinery use, reducing the manpower, specializing the cultivations and changing their practices to obtain bigger benefits. The pressure in favor of increasing the yield and the size of the exploitations has made that the traditional mixed farms, a system very integrated in the one that few external impacts were generated, have disappeared almost completely.
The third agriculture type understands all the other agricultural systems and of subsistence. It is systems of low external contribution and located in dry lands, marshy lands, high lands, savannas, swamps, areas semidesérticas, mountains and hills and forests. In these areas the cultivation systems are complex and diverse, the yield of the crops under, and the life of their inhabitants often depends on the wild resources, besides the own agricultural production. The exploitations are very far from the markets, they are in fragile or problematic floors, and it is not very probable that the agricultural scientists visit them or that they are studied in the investigation centers.
Their productivity is also low: the yield of the cereals is of only 0,5 to 1 ton for hectare. The poorest countries spread to have a higher proportion of these agricultural systems. By the middle of the decade of 1990, near a 30 to 35% of the population of the planet, between 1.900 and 2.100 million people, grace subsists to this third and forgotten agriculture form. This whole people are even this way excluded today of the politics of the governments' development that concentrates on highly productive lands.
I IMPACT OF THE SUSTAINABLE AGRICULTURE
In spite of the improvements carried out in the production of foods, the challenges have not made more than to begin. The world population will reach between the 8.000 and 13.000 million people. Appealing to the lowest, and given estimates the not very equal access to the resources that it prevails at the present time, will even be necessary that the agricultural production increases in a substantial way so that they can stay the current nutrition levels. Without a very considerable growth, the perspectives of many inhabitants of the poor countries are somber.
In the last 50 years, the politicians of agricultural development have had a remarkable success in potenciar the contributions or external entrances as means to increase the production of foods, what has produced an attractive growth in the global consumption of pesticidas, inorganic fertilizers, animal piensos, tractors and other machineries. These external contributions, nevertheless, they have replaced the resources and natural processes of control, making them more vulnerable. The pesticidas has replaced to the biological means, mechanics and of cultivation to control the plagues, the weeds and the illnesses; the farmers have substituted the manure, the vegetable payment and the crops nitrogen fijadoras for inorganic fertilizers; the information to make administration decisions comes from the commercial suppliers and of the scientists, not of local sources; and the fossil fuels have replaced to the energy sources generated locally. The specialization of the agricultural production and the decline associated of the mixed farm have also contributed to this situation. Those that in the past were valuable interior products they have become today waste products.
The main challenge to which faces the sustainable agriculture is to improve the use that is made of these interior resources. This can be made minimizing the contributions from the exterior, regenerating the interior resources more quickly or combinations of both. The sustainable agriculture is, therefore, a system of production of foods or fibers that it pursues the following objectives in a systematic way: 1) an incorporation bigger than the natural processes, as the cycle of the nutrients, the fixation of the nitrogen and the relationships plague-depredador to the processes of industrial production; 2) a reduction of the use of the external contributions not renewable that more damage can cause to the environment or the health of the farmers and consumers, and a more methodical use of the other contributions, of face to minimize the variable costs; 3) a more equal access to the resources and productive opportunities and the transition to fairrer agriculture forms from the social point of view; 4) a bigger productive use of the biological and genetic potential of the vegetable species and animals; 5) a bigger productive use of the knowledge and local practices, including innovative focuses even not completely understood by the scientists neither adopted by the farmers; 6) an increment of the self-sufficiency of the farmers and the rural towns; 7) an improvement of the balance among the shepherding patterns or exploitation, the productive capacity and the environmental limitations imposed by the climate and the landscape to guarantee that the current levels of production are sustainable long term; 8) a profitable and efficient production that makes stress in the integrated agricultural administration and the conservation of the floor, the water, the energy and the biological resources.
When these components unite, the agriculture becomes integrated agriculture, and their resources are used with more efficiency. The sustainable agriculture, therefore, aspires to the integrated use of a great variety of technologies of administration of the plagues, the nutrients, the floor and the water. It aspires to a bigger diversity of exploitations in the breast of the farms, combined with bigger bonds and flows among them. The secondary products or waste of a component become contributions to another. When going replacing the external contributions for the natural processes, the impact on the environment diminishes.
The big challenges to those that she/he faces the sustainable agriculture in each one of the three agricultural areas are very different. In the industrialized agriculture of Europe and America of the North, it is to reduce the use of external contributions and the variable costs substantially with the purpose of maintaining the profitability. Small reductions could be accepted in the yield, given the current sobreproducción level. In the areas of the call green revolution, the challenge is to maintain the yield and the current level of sobreproducción reducing the damages at the same time to the environment. In the diverse and complex lands it is to increase the yield for hectare without damaging the natural resources.
The new evidences coming from farms and communities from all over the world show today that the sustainable agriculture is possible in these three regions: 1) in the diverse, complex lands and poor in resources of the Third World, the farmers that have adopted the technologies regeneradoras have duplicated or triplicated the yield of their crops, often with little or any external contribution; 2) in the lands of high and in general irrigated contributions, the farmers that have adopted technologies regeneradoras have maintained their high yields, reducing the external contributions substantially; 3) in the industrialized agricultural systems, a transition to the sustainable agriculture could mean a descent in the yield for hectare from a 10 to 20 short term%, but it would be profitable for the farmers.
All these successes have three elements in common. They have made use of technologies that conserve the resources, as the integrated administration of the plagues, the conservation of the floor and the water, the one recycled of nutritious, the multiple cultivations, the reception of water, the one recycled of waste, and so forth. In general terms, there have been initiatives on the part of groups and communities at local level, as well as certain support on the part of institutions government non government y/o.
With everything, in most of the cases it is located initiatives. They are not more than isolated successes. This is due to the absence of a fourth element: a favorable environmental politics. In their majority, the existent politicians continue favoring an agriculture that depends on contributions and external technologies actively. These politicians constitute one of the main obstacles in the road toward a more sustainable agriculture.
THREATEN AND Obstacles
In spite of the viability of a more sustainable agriculture that would benefit the farmers, the rural communities, the environment and the national economy, they continue existing many obstacles and threats. Many of the existent structures of power are threatened by the change, and it can be impossible that everybody benefits of her short term. The threats arise from the international level to the local.
At international level, the markets and the commercial politicians have spread to reduce the price of the goods, diminishing the benefits of the farmers and the economies. Only in the last 10 years the prices had descended, for half term, 50 percent. The companies agroquímicas, on the other hand, will try to protect their markets of all option that it implies a reduction in the use of their products.
At national level, it is necessary to determine which they are the political macro and micro-economic that continue hindering the development of a more sustainable agriculture, and to change them. In some cases this will be politically very difficult, especially when it is to put into practice some reformations that should give to the farming guarantees to invest in practical sustainable.
The bureaucratic nature of the big institutions constitutes a threat more. They find difficult to work in a way that grants to be able to the local communities, since this supposes to lose part of his. Of similar way, the conservative nature of the universities and the teaching institutions it is an obstacle for the appearance of new professionals guided toward the sustainable agriculture. In their biggest part, these are shown reticent or unable without more than forming professionals of the agriculture able to work with and for the farmers.
Lastly, the own farmers face the costs that it supposes the transition to practical and sustainable agricultural technologies and to their learning.