Nutrient Cycling in Southeast Asia

(Image retrieved: http://www.merrytravelasia.com/admin/Administrator/images/users_images/map2.gif )
(Image retrieved from: http://www.merrytravelasia.com/admin/Administrator/images/users_images/map2.gif )

We would now discuss the human activities and nutrient cycling in a more focused scale, specifically in Southeast Asia. Countries in Southeast Asia includes Brunei, Cambodia, East Timor, Indonesia, Laos, Malaysia, Burma, Philippines, Thailand, Vietnam and Singapore. Many of which are leading producers of goods such as coffee, sugar, palm oil, cocoa and rice. For example, according to the Southeast Asia Commodity Digest, Malaysia and Indonesia are the world’s biggest producers of palm oil, Vietnam is the world’s Number 2 coffee producer, and Vietnam and Thailand are two of the world’s biggest rice growers. Southeast Asia, being one of the most dynamic, fast growing regions in the world today, with population and economic activity increasing on a rapid speed, coupled with reliance on agriculture in providing livelihoods for a large segment of the population, and dependence on natural resources and forestry to drive development, the activities in Southeast Asia has a large influence in affecting the nutrient cycles and this influence may be increasing.

Figure A and B
Figure A and B

Firstly, agricultural practices in Southeast Asia includes the extensive usage of different fertilisers to increase crop yield which results in many negative effects to the environment and several nutrient cycles, especially, the nitrogen cycle and the phosphorus cycle. During 1995—2005, nitrogen usage increased 44% in Thailand, 41% in the Philippines, 37% in Indonesia, and 35% in Vietnam (Figure A and B). Fertiliser use has intensified most in Vietnam, at 0.16 ton per hectare in 2000 and a slightly lower 0.13 ton per hectare in 2005. This extensive usage of fertiliser which has increased even more since 2005, have resulted in effects such as eutrophication issues and more importantly, the excessive release of large amounts of nitrogen and phosphorus in available forms that results in changes in the nitrogen cycle and phosphorus cycle respectively.

(Image retrieved from: http://3.bp.blogspot.com/_n9nytwY_jek/TS8oQCN8xHI/AAAAAAAAACU/v5pYyLVVZkU/s640/eutrophication.gif )
(Image retrieved from: http://3.bp.blogspot.com/_n9nytwY_jek/TS8oQCN8xHI/AAAAAAAAACU/v5pYyLVVZkU/s640/eutrophication.gif )

An example of this negative effect of release of nutrients that are eventually released into the environment include the Karangkates Reservoir in Indonesia, where the contamination of reservoir water by nutrients flowing into reservoir from agricultural, domestic and industrial sources resulted in blooms of blue-green algae, dead fish and unpleasant odours.

 

Other agricultural practices include the clearing of nonagricultural areas (for example, forestlands, grasslands, and wetlands or peatland) to be converted into agricultural space for the production of beans, coffee, natural rubber, palm oil, rice (paddy), sesame seed, soybean, and vegetables. In addition, forest fires which may be started either by farmers who are clearing land or by natural dry seasons, count among the main factors contributing to biodiversity and forest loss in Indonesia and the Philippines.

(Image retrieved from: http://www.intechopen.com/source/html/42197/media/image1.png )
(Image retrieved from: http://www.intechopen.com/source/html/42197/media/image1.png )

An example of the conversion of land use is shown in this diagram, where the increase in agricultural areas for palm oils are accompanied by large amounts of forest lost in Malaysia and Indonesia. This results in the decrease in carbon sinks further changing the original natural carbon cycle, by decreasing amount of plants that act as exchange pools, and increasing amount of carbon and their resident time in the atmosphere.

Livestock Production in Southeast Asia
Livestock Production in Southeast Asia

The livestock production in Southeast Asia has been increasing since the 1970s according to the table, and over the last 4 decades, the population of major farm animals has increased significantly. Also, since 1965, the cattle population has increased by 98% while pig and chicken populations have increased twice the original and seven times the original, respectively. The increase in the livestock production not only results in higher occurrence of overgrazing which leads to the land losing their original nutrients and become dried up, already affecting several nutrient cycles [lesser exchange pools -> increase amount of element and their resident time in other components of the cycle], wastes of these livestock results in the release of large amounts of nitrogen in the form of ammonia into the environment. This would thus affect the nitrogen cycle as well.

Screen Shot 2014-11-07 at 11.50.56 amIn addition, with many countries in Southeast Asia becoming more and more developed, there has been an increase in the number of vehicle ownerships in Southeast Asia. Vehicle emissions is a contributor to the air pollution and plays a role in affecting several nutrient cycles in the region. This is a call for concern especially in many countries in Southeast Asia, where the enforcement of vehicle maintenance and control in developing countries such as Thailand, Malaysia and Indonesia are very lax.

" We make the world we live in and shape our own environment." -Orison Swett Marden