high energy foods for men
Food and energy for man is very important in the world. Approximate yields of major food crops at
three levels of auxiliary energy, and three levels of protein content are shown
in table 3-2. Millions of people are not getting enough calories of food;
millions of other are not getting enough protein, especially children who have
a higher requirement for growth. Thus, it is important to consider both food
for man and protein quality. From table 3 – 2 we see that world average yield
is two to three times less than that of high yields in affluent countries because
most of the world’s cultivated acres do not have the benefit of high – energy subsidy.
Average yields are, in fact, very close to the bottom; that is, world averages are little better than that reported
from the very poorest countries. To double food yield in the latter requires a
tenfold increase in fuel, fertilizers, and pesticides. Those who think that food
for man we can upgrade agricultural production in ‘’undeveloped’’ countries
simply by sending seeds of new varieties and a few ‘’agricultural advisors’’
are tragically naïve. Crops highly selected for industrial agriculture must be
accompanied by many calories of fuel which, of course, the developed countries
are hoarding for themselves a second point to note from table 3 -2 is that, as
always, quality comes at the expense of quantity. Yields of a high protein
crop, such as soybeans, average one half to one third less than that of low or
moderate protein content crops. Getting one’s protein from meat, however
desirable from the nutritional standpoint, does not help the per – unit – area –
yield problem since, as we have seen in our discussion of food chain dynamics, food
for man there is at least an 80 percent loss in transfer from grain to meat.
Table 3 -2 ,
annual yiels of edible food and estimated net primary production of major food
at three levels of energy subsidy and three levels of protein content.
W see from table 3 –
3 that in 1970 man harvested about 5.3. 1015 kcal of food, 99 percent from the land and 78
percent from plants. This would theoretically give the approximately 4 billion
(4.109) people in the world their minimum annual requirement of 1
million (106 ) kcal even allowing for you unavoidable waste, if Food
for man were evenly distributed. But, of course, it is not, and probably can
never be because of the problems of distribution, transportation, economics,
and so on.
The estimate of 5.1015 kcal harvested is about 1
percent of global net primary production and 0.5 percent f gross. It would seem
that man is not yet making much of a dent in the phosynthetic capacity of the
earth, but the real impact looks quite different when we consider the
following.
1.
1. The
oceans are no bonanza since only animal food can be conveniently harvested, and
only very limited areas are rich c=enough to support intensive fisheries. Most fishery
experts believe that man is already harvesting all he can get from the natural
production of the sea. To ‘’cultivate’’ the sea on any large would require huge
investments of energy, the cost – benefits for which might be negative Food for
man.
2. 2. Since
domestic animals outnumber people 5 to 1 terms of equivalent food requirements,
then man plus his animals are taking just about 6 percent of net production of
the biosphere or at least 12 percent of that of the land area, and this
includes not only cultivated land and pasteres, but much ‘’wild land’’ on which
animals graze.
3. 3.
All
of the best land suitable by natural fertility and slope for intensive ‘’row
crop Food for man’’ agriculture is now in cultivation, this amounts to about 12
percent of land area. Only 24 percent of land is truly arable, and to get the
additional 12 percent into intensive food production would require energy
subsidies much greater than that required for the good land. An additional 25
percent of land is in pastures, much of which are marginal in productivity.
4.
To
try to cultivate the huge area of steep land and remote grasslands and deserts
is to invite trouble with other necessary resources, such as water. Attempts to
cultivate too much land contributed to the failure of past civilizations: even
if modern technology is capable of reducing environmental degradation. The cost
remains formidable. The old cliché that ‘’man does not live bread alone’’ must
certainly be heeded.
Perhaps the best
way to view the food problem is to consider it from the per capita viewpoint. To
provide the diet now consumed by an American, about 2.5 acres (1 hectare) are
required when we consider land area required to produce meat, orange juice, and
leafy vegetables along with staple grains. Another acre is required to produce
fibers (wood, paper, cotton, and so on). As of 1970 there were only 10 acres of
land per person average for the whole world. If population doubles in the next
50 years there will be only be 5 acres (2 hectares) per capita to provide all
requirements – water, oxygen, waste treatment, fibers, living space,
recreation, as well as food for man.
We cannot hope to do justice to the subject of ‘’food for man’’in
this brief introduction. Relationships are extremely complex and there is much
controversy. For further reading we recommend the three – volume treatise the
world food problem and George borgstrom’s books (1967, 1969). But we must warn
you that these are mot easy reading, and that th=ere are no easy ‘’quick – fix’’
solutions.
The whole gambit
of natural and cultivated net cultivated net primary production is summarized. When
we look at it from the basic energy standpoint there is no difference between
man’s crops and nature’s crops. Given sunlight, nutrients, water, and adapted
plants, net production is a function of available supplemental energy – tides in
case of salt marsh, and fuel in case of agriculture. Just because man does not
harvest the net production of the marsh grass does not mean it is valueless to
him. Useful work of waste assimilation and recycling worth many dollars is
accomplished and food for man the seafood flowing off the end of the food chain
is free except for the cost of harvesting and processing.
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