Annex identification of different global production systems and their relative productivity
Wetland rice cultivation (intensive)
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- Main environmental concerns
- 1.3.2 Irrigated (intensive)
1.3.1 Wetland rice cultivation (intensive)Wetland rice cultivation is typically carried out in lowland, submerged soils in East and South Asia. The system supports an agricultural population of nearly 860 million and supports c. 1.5 billion people in total (FAO, 2003). The benefits of growing in flooded soils suit rice cultivation well and provide the necessary fertile soils and an abundance of freshwater during the wet or monsoon seasons. Low-lying land, including valley bottoms and the Indo-Gangetic Plains, covering much of Pakistan and Bangladesh as well as parts of India, have traditionally been associated with rice cultivation. In Korea, agriculture tends to be small–scale, with commercial family farms averaging around 1 ha. More than half of Korean total agricultural income is derived from rice crops (Sahrawat, 2006). Whilst rice is the main output of this system, other food and cash crops are grown, and poultry and livestock are reared for domestic purposes. The system requires high input in the form of rain, with 60% of holdings having irrigation schemes. Rice production is very labour intensive and the systems can suffer from human pressure with 5.5 people per hectare of land, thus exerting significant pressures on natural resources. Table 6. Characteristics of wetland rice cultivation systems
Wetland rice cultivation is a source of CH4. It is projected that global rice production could increase by 65% between 1990 and 2025 which would lead to an increase of methane emissions from a 92 Tg CH4 y–1 to 131 Tg in 2025 (Bouwman, 1991). Alongside rice production, rice-fish systems have developed in southeast Asia (Ruddle, 1982). These are regarded as offering ecologically and economically sustainable, subsistence forms of agriculture (Datta et al., 2009). Under such systems CH4 emissions were found to increase while nitrogen dioxide decreased. Taking into account the increased carbon credit payments which would be needed to offset the CH4 emissions, the higher fish and rice yields and profits offered by this system are still of greater economic benefit (Datta et al., 2009). The major future changes in this farming system are expected to be increased intensification and diversification of crop production with little increase in cropped land area. Diversification could include focusing more on small scale livestock production as well as the expansion of small-scale on-farm aquaculture (ponds or rice-fish culture). If average farm sizes increased, in addition to farm mechanization, household incomes may increase thus reducing poverty. However, there are potential environmental implications associated with increasing intensification. The future of the wetland rice cultivation system is also likely to encounter challenges relating to declining rice prices and increasing labour costs, thus making it less attractive to use high levels of inputs. As a result, this could slow down the current increases in rice productivity. These low prices reflect declining global prices, but may also be as a result of government attempts to keep rice prices low to satisfy urban consumers. The system is also likely to be faced with challenges relating to population pressure, climate change and land degradation, particularly in South Asia. With an increasing population to support, natural resources will be under greater pressure. Great variability in rainfall as a result of climate change may put further stress on already arid areas, so better water management and soil conservation is going to be necessary until population growth slows down (Dixon et al., 2001). 1.3.2 Irrigated (intensive)Irrigated farming systems are found in the arid areas of northern and central Mexico, coastal and inland Peru, Chile and western Argentina, with the largest irrigated areas being in India, China and Pakistan, and important areas in Egypt and Saudi Arabia. Land area under irrigated farming systems totals nearly 200 million ha and this production system is important for national food security and exports in many countries (FAO, 2009). In order to help meet future demands, irrigation systems are likely to require increased performance levels. Smallholder irrigated farming systems tend to require large-scale irrigation schemes in comparison to the scale of the farming. For example, the Ceyhan Aslantas Project was funded by the Turkish Government in the 1960s and completed in 1985. The aim of the project was to irrigate 97,000 ha of land in the Ceyhan basin, as well as generating power and reducing flooding impacts. The dam provides net irrigation for 84,000 ha of land (95% of the originally planned total). In terms of production, cropping intensity is 34% more than expected. As a result of unexpected cropping patterns, production values are less than predicted. Cotton, wheat and groundnut yields did not reach their predicted values, whilst there were increases in maize and watermelon yields at 200% and 50%, respectively. Predicted yields resulting from this project were: cotton (4.0 t/ha), wheat (4.0 t/ha), maize (4.0 t/ha), groundnut (3.5 t/ha) and watermelon (2.5 t/ha). Actual yields were cotton (3.0 t/ha), wheat (2.9 t/ha), maize (8000kg/ha), groundnut (2.8 t/ha) and watermelon (3.8 t/ha) (World Commission on Dams, 2000). Growth in irrigation schemes, as well as a lack of water management and integration of infrastructure have encouraged widespread environmental, economic and social problems. In order to prevent further degradation, irrigation schemes should shift towards being run at the community level on a participatory basis. However, this will involve time and money (Dixon et al., 2001). Table 7. Characteristics of irrigated production systems
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