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.  THE END.