Wednesday, April 20, 2016

TOPIC 3 : AGRO-­‐ECOLOGICAL SYSTEM

Industrial agriculture

The links between industrial agriculture and climate change are twofold. On the one hand, industrially produced food systems are energy-intensive and fossil-fuel based, and thus contribute significantly to climate change. On the other hand, the crops grown in the genetically homogeneous monocultures that are typical of chemical farming are not resilient to the climate extremes that are becoming more frequent and more violent.
Industrial agriculture originated in the 1960s when petrochemical companies introduced new methods of intense chemical farming. For the farmers the immediate effect was a spectacular improvement in agricultural production, and the new era was hailed as the "Green Revolution." But a few decades later, the dark side of chemical agriculture became painfully evident.
It is well known today that the Green Revolution has helped neither farmers, nor the land, nor the consumers. The massive use of chemical fertilizers and pesticides changed the whole fabric of agriculture and farming, as the agrochemical industry persuaded farmers that they could make more money by planting large fields with a single highly profitable crop and by controlling weeds and pests with chemicals. This practice of single-crop monoculture entailed high risks of large acreages being destroyed by a single pest, and it also seriously affected the health of farm workers and people living in agricultural areas.
With the new chemicals, farming became mechanized and energy-intensive, favoring large corporate farmers with sufficient capital, and forcing most of the traditional single-family farmers to abandon their land. All over the world, large numbers of people left rural areas and joined the masses of urban unemployed as victims of the Green Revolution.
The long-term effects of excessive chemical farming have been disastrous for the health of the soil and for human health, for our social relations, and for the natural environment. As the same crops were planted and fertilized synthetically year after year, the balance of the ecological processes in the soil was disrupted; the amount of organic matter diminished, and with it the soil’s ability to retain moisture. The resulting changes in soil texture entailed a multitude of interrelated harmful consequences — loss of humus, dry and sterile soil, wind and water erosion, and so on.






The ecological imbalance caused by monocultures and excessive use of chemicals also resulted in enormous increases in pests and crop diseases, which farmers countered by spraying ever-larger doses of pesticides in vicious cycles of depletion and destruction. The hazards for human health increased accordingly as more and more toxic chemicals seeped through the soil, contaminated the water table, and showed up in our food.
In recent years, the disastrous effects of climate change have revealed another set of severe limitations of industrial agriculture. As Miguel Altieri and his colleagues at SOCLA (the Sociedad Cientifica Latinoamericana de Agroecologia) point out in a recent report, the Green Revolution was launched under the assumptions that abundant water and cheap energy from fossil fuels would always be available, and that the climate would be stable. None of these assumptions are valid today. The key ingredients of industrial agriculture — agrochemicals, as well as fuel-based mechanization and irrigation — are derived entirely from dwindling and ever more expensive fossil fuels; water tables are falling; and increasingly frequent and violent climate catastrophes wreak havoc with the genetically homogeneous monocultures that now cover 80 percent of global arable land. Moreover, the practices of industrial agriculture contribute about 25 to 30 percent to global greenhouse gas emissions, further accelerating climate change.
Our fossil-fuel based industrial agriculture contributes to greenhouse-gas emissions in several distinct ways: directly through the fuel burnt by agricultural machinery, during food processing, and by transporting the average ounce of food over a thousand miles "from the farm to the table"; indirectly in the manufacture of its synthetic inputs, e.g. of nitrogen fertilizer from nitrogen and natural gas; and finally by breaking down the organic matter in the soil into carbon dioxide (during large-scale tillage and as a consequence of excessive synthetic inputs), which is released into the atmosphere as a greenhouse gas. In addition, massive amounts of methane (a greenhouse gas many times more potent than CO2) are released during large-scale industrial cattle ranching.
The degrading of healthy organic soil by chemical fertilizers and pesticides increases the soil's vulnerability to drought by reducing its capacity to capture water and keep it available for crops. A further devastating effect of the over-fertilization that is typical of current chemical farming practices is the nutritional overload in our waterways, caused by runoffs of agricultural nitrates and phosphates, which lead to oxygen depletion in rivers and to so-called "dead zones" in the oceans, which are no longer inhabitable by most aquatic life.
From a systemic point of view, it is evident that a system of agriculture that is highly centralized, energy-intensive, excessively chemical, and totally dependent on fossil fuels; a system, moreover, that creates serious health hazards for farm workers and consumers, and is unable to cope with increasing climate disasters; cannot be sustained in the long run.







DIFFERENT CLIMATES IN THE WORLD

 1)Tropics
2) Temperate
3) Tundra
4) Desert
















WATER






Soil
(i) The unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants.

(ii) The unconsolidated mineral or organic matter on the surface of the Earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- microorganisms, conditioned by relief, acting on parent material over a period of time.

A product-soil differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.




HUMAN RESOURCES

Human Resource Development is an important factor in capacity building and improving the overall efficiency of functionaries involved in implementation, monitoring, evaluation, research and extension programmes. Training is a major component of Human Resource Development. Systematic training, planning, management and its implementation by making best utilization of resources available within the country helps in bringing about desirable changes in knowledge and upgrade skills of extension functionaries associated with the process of agriculture development. The training infrastructure has been created to meet out the training requirements of all levels of extension functionaries, farm youth and farmwomen. Looking into the importance of training in capacity building of extension experts and farmers, this scheme is selected for the strengthening of extension services and dissemination of agricultural technology to the farming community.







IMPACT OF CLIMATE CHANGE

The greenhouse effect
The earth is surrounded by an atmosphere through which solar radiation is received. The atmosphere is not static but contains air, in constant motion, being heated, cooled and moved, water being added and removed along with smoke and dust.  Only a tiny proportion of the sun's energy reaches earth and some of this is reflected back into space (from clouds etc.). When the radiant energy reaches the land surface, most of it is absorbed, being used to heat the earth, evaporate water and to power photosynthetic processes.
The earth also radiates energy but, because it is less hot than the sun, this is of a longer wavelength and is absorbed by the atmosphere. The Earths atmosphere, thus acts like the glass of a green house, hence the 'greenhouse effect'. 




Global warming 

The term used to describe a gradual increase in the average temperature of the Earth's atmosphere and its oceans, a change that is believed to be permanently changing the Earth's climate.




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