Theme 3

Better environments from better agriculture

What is the challenge?

Agricultural impacts on the environment occur both where the agricultural activities are carried out and offsite. In addition to being a potential source of environmental degradation, agriculture can also be adversely affected by the environmental impacts of other human activities. Since the mid-20th century, increases in food production have been met more by increasing crop yield than by expansion in crop areas. With increases in population over the last 50 years, it is estimated that the yield growth in crops has saved over a billion hectares of land from the plough. Food demand will continue to grow at around 2% annually so yield must grow at the same rate if remaining non-agricultural land is not to be developed for farming. Increasing yield through better technologies offers the best opportunity to minimise agricultural impacts on the global environment, while accommodating the huge pressures that climate change will inevitably exert on agriculture in the medium to long term.

Agriculture is by far the greatest consumer of water resources in most developing countries, often using 70-80% of freshwater supplies. Water is becoming scarcer because of its diversion to non-agricultural uses. The development of new water resources for irrigation was an important factor in yield increases in the past, but it has significantly slowed. Policies involving water ownership and pricing are crucial for improving water use, as are the governance arrangements that ensure revenue for water use is collected and managed so that the real costs of the water are recovered.

Loss of agricultural land as a consequence of economic growth and urban expansion is significant in much of Asia. Degradation of land resources often occurs over large scales, often slowly, and has the potential to reduce productivity, and to seriously compromise the gains from research. Major issues include erosion of upland areas, dryland salinity and sodicity, soil nutrient depletion and structural decline, soil acidification, vegetation degradation and contamination of soils by persistent chemicals. Poorly managed irrigated areas are prone to salinisation and waterlogging.

Maintenance of soil quality is crucial for economically and environmentally efficient use of inputs including fertilisers and energy. Organic fertilisers and biological nitrogen fixation have a role to play here. There is scope for research to develop win-win solutions -- higher yields and minimal environmental damage.

Vegetation is also subject to degradation, and this is particularly significant in the agricultural management of rangelands in arid and semi-arid climates. In wetter areas, poor management can result in amplification of pest problems including weeds, soil-borne pathogens and insect pests, and loss of soil and associated problems caused by erosion.

Productive peri-urban farmland suffers from pollution through the indiscriminate disposal of contaminated urban waste. Localised contamination of soils can reduce the quality and marketability of agricultural products. More widespread, and usually less acute and unintentional, contamination can affect land and water resources. Such effects include deposition of aerially transported materials (particularly acidity), careless use of agrochemicals in intensive systems, and point sources of pollutants of water bodies. On the positive side, urban and industrial wastes can sometimes be used for soil improvement. Agricultural research can play an important role in ameliorating most of these external pressures on its natural resource base.

How can ACIAR respond?

Except in a few cases, such as the adoption of irrigation and fertilisers, there are few readily adoptable and economically attractive changes in farm practices for improvement of agricultural land and water resource management. Individual farms are generally small in relation to the scale of processes such as salinisation or decline in water quality. The impact of environmental degradation may be borne by others beyond the farm boundary, and the costs are not borne by individual farmers.

Because of the scale of the processes, multiple participants, not just individual farmers, are required to bring about solutions. This brings the need to recognise the 'people dimension' of solutions to land and water resource management. Policy and governance frameworks are also required to promote actions by multiple parties, including the farmers. While continuing to support technical research on the environmental impacts of agriculture and matching land use to capability, ACIAR will give increased emphasis to participatory approaches to resource management (especially of common resources), and to economic and policy research.

The focus areas

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