Agriculturists are often asked if tree crops such as pine,
fruit trees, rubber and oil palm or annual crops such as wheat,
maize, rice or soya bean are friendlier for the environment.
This article will explore the merits and demerits of planting
tree crops or annual crops vis a vis its environmental impact.
One of the major contributors to environmental damage during
the planting of annual crops is the heavy usage of machineries
in all aspects of cultivation of the crops. There is
significant use of mechanisation from seed planting to the
harvesting and threshing of the crop. Early in the 19th century,
a farmer could produce food for 2.5 people and by 1999 due to
advances in agricultural technology, a single farmer could feed
over 130 people. Modern harvesters such as combined harvesters
and planters are extensively used in the planting of various
crops in most parts of the world. While mechanisation increases
productivity and lowers the cost of production, it also
contributes towards environmental destruction. Most of these
machineries are bulky and as they move around the fields, they
bring destruction to the top soil causing destruction to the
microorganisms found in the soil.
Soil is a favourable habitat for microorganisms and is
inhabited by a wide range of microorganisms including bacteria,
fungi, algae, viruses and protozoa. Microorganisms are found in
large numbers in soil; usually between one and ten million
microorganisms are present in each gram of soil and with
bacteria and fungi being the most prevalent. Apart from that,
soil organisms are very important as almost every chemical
action and reaction that takes place in soil involves active
contributions from soil microorganisms.
They play an active role in enhancing soil fertility by
assisting with the recycling of nutrients such as carbon and
nitrogen which is essential for plant growth. Microorganisms
also help with the decomposition of organic matter in soil into
nutrients. An example would be nitrogen fixing bacteria
transforming nitrogen gas present in the soil into soluble
nitrate compounds which enrich the soil and is absorbed by the
plant. Other soil microorganisms produce hormones that can
improve plant health and contribute towards higher yield.
Microorganisms are influenced by the nature, properties and
arrangement of soil particles. They also modify soil particles
and their arrangements. Microbial life in soil is also
indirectly influenced by surface interactions. Some
microorganisms also burrow into and churn up the soil which
improves soil structure and aggregation. Microorganisms have
the ability to protect plants from antagonistic pathogens as
some can dissolve minerals and provide nutrients in dissolved
mineral form to plants. Apart from microorganisms, there are
also earthworms that take in dead organic matters from soil,
ingest it, excrete the nutrient rich casts in the soil and help
to improve aeration, water infiltration, drainage and enhance
nutrient availability and cycling. These microorganisms and
earthworms which enrich the soil are usually killed by the use
of machineries and continued use of machineries in the field do
not enable these microorganisms to be re-established.
Another factor to be considered for annual crops is the current
practice of double or even triple cropping per year which causes
continuous damage to the top soil without providing opportunity
for the soil to rejuvenate. Over-tilling and over-ploughing soil
destroys natural soil structure with decreased soil pore size,
breakdowns in soil aggregates and decreased pore space which
curbs good air and water flow. Continuous use of heavy
machinery causes soil compaction which makes it difficult for
microorganisms, earthworms and small insects to breed. This also
results in poor internal drainage, creates possible run off,
inhibits root development and breeds unhealthy plants. Soil
compaction also causes water that enters the surface of the soil
to be perched on the sub surface of the soil, saturating and
ponding the surface of the soil while by right it should have
permeated into the soil. Thus soil compaction has a destructive
effect on the soil and the environment.
Smoke from these machineries also pollutes the air which is not
only detrimental to health but causes chemical pollution of the
crops in the form of acid rain. Apart from that, pollution
caused by these machineries causes depletion of the ozone layer.
In some underdeveloped countries, the stalks of annual crops are
burnt after the crop has been harvested, which releases carbon
dioxide into the atmosphere. The natural biodiversity of
plants, animals and microbes function in many ways to enhance
the quality of life enjoyed by the human beings. But in the
process of providing food for the human beings, biodiversity has
taken a back seat. In the case of rice, vast areas of wetlands
have been drained to plant rice which upsets the pre-existing
biodiversity. The same goes to vast tracts of land in North and
South America where prairies have gradually been converted into
field growing crops such as wheat and maize. The conversion of
these areas have totally eradicated some indigenous plants and
animals. The wild population of the American bisons that
inhabited the prairies were practically eradicated in the
process of establishing large farms to grow wheat to feed the
American population. Historically they ranged across half of
North America and numbered in the millions before being reduced
to a countable number within a period of two centuries. Their
habitat which were the grassland and meadows that were the
former prairies have made them an endangered breed of animals.
Establishing such farms did not just upset the ecosystems that
had been in place there but also caused a gradual extinction of
a breed of animal that is part of the American history.
How land is used to produce food can have an enormous effect on
the environment and its sustainability. Environmental groups in
the United States have mounted attacks on fast food chains such
as Kentucky Fried Chicken (KFC) and Pizza Hut because of the
adverse effects these organisations have created in the food
production chain in the country. Intensive breeding of livestock
and poultry for the restaurants have resulted in deforestation
in countries such as Brazil, land degradation, and the
contamination of water and other natural resources. For every
pound of red meat, poultry, eggs and milk produced, farms fields
in these countries lose about five pounds of top soil of their
field. The water used for meat breeding comes to about 190
gallons per animal per day or ten times of that used by an
average family. Overall, animal farms use about 40% of the
world's total production of grain and nearly 50% of the grain
production in United States goes towards feeding livestock, not
hungry mouths elsewhere in the world. (Source: South End Press,
2000). The demand for these crops are so great that genetically
modified (GM) food crops are planted in some developed countries
to meet the demand for them. While the peril of genetically
modified crops are yet to be seen in the long term, there is
already strong resistance from some Western NGOs and protests
have been mounted against planting and exporting of GM crops.
New concepts such as industrial agriculture have also been
mooted so that production of food crops can be enhanced to meet
demand for such food products. Planting of food crops is no
longer considered essential farming but is increasingly viewed
as production of a commodity to meet the demands of customers
such KFC and Pizza Hut.
Much of the best agricultural land in the world is used to
plant non food crops such as cotton, tobacco, sugar cane, cocoa
and food flavour cum oil extractant crops such as soya bean.
Soya bean has been found to be the cause of extensive clearing
of forest land in South America. Used as a fodder and oil
extractant, it requires more than four hectares to produce the
same amount of oil extracted from every hectare of oil palm
land. In other words for every one hectare of oil palm land you
need more than four hectares of land to produce a similar amount
of oil from soya bean. So extensive is the use of land and
machinery in cultivating this crop in Brazil that vast areas of
land in the Matto Grasso and Para districts has been cleared to
plant this crop. What was once a thriving ecosystem supporting
more than 300 tree species per hectare has been destroyed with
the conversion into soya bean farms. The whole process of the
cultivation of the soya bean crop from planting to harvesting is
fully mechanised and the use of sophisticated machineries causes
severe damage to the top soil and the environment. In the past
three years nearly 70,000 hectares of primary rainforest has
been destroyed to plant the crop. Big earth movers are sent into
the jungle to bulldoze the forest trees and then the logs are
dumped into pits and burnt. The trunks take weeks to burn and
the smoke smoulder for months causing environmental pollution.
Brazil produced more than 50 millions of soya in an area of
about 23 million hectares and has overtaken the US as the
leading producer of soya bean. (Source: Common Dreams. Org.
July, 2006)
On the other hand, tree crops cause minimum damage to the
environment through the minimal use of machines. Limited usage
of mechanical equipments is one of the reasons for tree crops
means less pollution to the environment. The most common piece
of machinery used is the farm tractor, utilised mainly for the
transportation of planting materials and harvested crops. Thus,
there is no continuous use of machinery such as those used in
annual crops which is heavily utilised through the entire
cultivation process.
Another key factor to note is that tree crops have a lifespan
ranging from 15 to 25 years thus causing minimum disruption to
the soil surface. Once planting has been carried out, the soil
is not tilled again until the next planting. In the case of oil
palm, replanting is carried out only every 25 years giving the
soil ample time to rejuvenate. Within this period,
microorganisms that enrich the soil are able to reestablished.
Apart from that, minimum disruption to the soil means other
organisms such as earthworms and insects are allowed to breed
and there is a continuous process of soil enrichment which does
not occur with annual crops.
With environmental friendly approaches such as `zero burning',
oil palms are felled, mechanically shredded and left to
decompose in the soil. By avoiding open burning, there is little
disruption to the top soil and microorganisms thus helping to
maintain the soil fertility. Oil palms and other tree crops also
provide ample space for flora and fauna to flourish during the
establishment and subsequent stages of growth of the trees.
Compared to other oil producing crops, a hectare of oil palm
produces 10 times more oil than other crops and an average yield
of between 4- 5 tonnes of crude palm oil per hectare makes oil
palms the most efficient oil bearing crop and the most efficient
crop in the world.
In conclusion, tree crops such as oil palm plantations are
'perrenial', providing more biodiversity and are more
environmentally friendly when compared to annual crops such as
soya bean. Thus, agriculturists and environmentalists normally
show a predilection for and embrace tree crops and plant these
whenever possible.
* This article was originally posted at Deforestation Watch
[http://deforestationwatch.org]. For changes and updates of this
article please visit
http://deforestationwatch.org/index.php?option=com_content&task=view&id=231&Itemid=43
About The Author: Simon Chambers, please visit Deforestation
Watch at http://deforestationwatch.org/. Deforestation Watch was
established to drive sustainability mainstream. Striving to be a
center of green news, solutions and all things green, we also
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