|
Showing 1 - 2 of
2 matches in All Departments
The world needs for food and fiber continue to increase. Population
growth in the developing countries peaked at 2. 4% a year in 1965
and has fallen to about 2. 1%. However, in many developing
countries almost half the people are under 15 years of age, poised
to enter their productive and reproductive years. The challenges to
produce enough food for this growing population will remain great
Even more challenging is growing the food in the areas of greatest
need. Presently the world has great surpluses of food and fiber in
some areas while there are devastating deficiencies in other areas.
Economic conditions and the lack of suitable infrastructure for
distribution all too often limit the alleviation of hunger even
when there are adequate supplies, sometimes even within the country
itself. World hunger can be solved in the long run only by
increasing crop production in the areas where the population is
growing most rapidly. This will require increased efforts of both
the developed and developing countries. Much of the technology that
is so successful for crop production in the developed countries
cannot be utilized directly in the developing countries. Many of
the principles, however, can and must be adapted to the conditions,
both physical and economic, of the developing countries.
Soil is formed from the physical and chemical weathering of
rocks-processes described historically because they involve eons of
time-by glaciation, and by wind and water transport of soil
materials, later deposited in deltas and loessial planes. Soil
undergoes further transformations over time and provides a habitat
for biological life and a base for the development of
civilizations. Soil is dynamic - always changing as a result of the
forces of nature and particularly by the influences of man. Soils
have been studied as long as history has been documented. W. H.
Gardner told of writings on clay tablets, dating about 1700 Be, in
his review, "Early Soil Physics into the Mid-20th Century;'
published in Volume 4 of this series. Those writings gave specific
instructions on cultivating the soil and seeding crops. Numerous
references to soil are found in historical writings, such as
Aristotle (384-322 Be), Theophrastus (372-286 Be), Cato the Elder
(234-149 Be), and Varro (116-27 Be). Some of the earliest
historical refer ences to soil 3000 or more years ago have to do
with erosional forces of wind and water. The study of soils today
has taken on increased importance because a rapidly expanding
population is placing demands on soil that has never before been
experienced. Soil scientists have professionally divided themselves
into separate disciplines-physics, chemistry, microbiology,
mineralogy, genesis, and the like. Studies range from very basic to
very applied, and to literally every corner of the earth, and ofthe
moon as well."
|
You may like...
One Life
Anthony Hopkins, Johnny Flynn, …
DVD
R305
Discovery Miles 3 050
|