Sunday, April 4, 2010

Agriculture and the challenge of Climate Change

Suman Sahai

Climate change is likely to have a long term impact on social, environmental, economic, technological and political processes. But its most destructive influence will be on agriculture and food production in the poor developing countries. These will be more susceptible to climate change damage than the temperate countries, many of which actually benefit from climate change. Changes in rainfall patterns and temperature regimes will influence the local water balance and disturb the optimal cultivation period available for particular crops, thus throwing food and agricultural production out of gear. According to climate estimates, agriculture in the productive areas of Africa and south Asia will be amongst the worst affected. Some estimates say almost 40 per cent of the production potential in certain developing countries could be lost. In south Asia, the biggest blow to food production is expected to come from the loss of multiple cropping zones. The worst affected areas are predicted to be the double or triple cropping areas, where two to three crops are produced in a year. To offset this loss, an effort must be made to convert single cropping areas into two crop zones. This can be done by efficient rain water harvesting and developing micro watersheds and water bodies so that in rain fed areas where one crop is being harvested today, water can be made available for a second crop.

Coping with the impact of climate change on agriculture will require careful management of resources like land, water and biodiversity. Food production can be stabilized and livelihoods secured if the impact of climate change is factored into the design and implementation of development programmes. Large scale awareness programmes are necessary to prepare farmers, who are today bewildered by the rapid fluctuations in weather conditions that are affecting their farming. Their traditional knowledge does not help them to manage the current anthropogenic changes.

It is necessary to develop and demonstrate successful, replicable models to enable agriculture and food production to both adjust to the changing climate, as well as mitigate

the emissions from crop production. Fortunately technologies and practices that can help to achieve this are now available. The real stumbling block is perhaps the mind set fixated on intensive, agrochemical based agriculture as the only option and the lack of political will to introduce the fundamental changes that are necessary to make agriculture sustainable and high yielding. A well articulated and focused advocacy position and an effective campaign is needed to bring about the required policy changes.

Making agriculture sustainable and reducing emissions

Practices in agriculture will need to shift from intensive, mechanized, water demanding agriculture to more sustainable, conservationist methods that give higher crop yields using less water. ‘More crop per drop of water’ is the strategy recommended to tackle drought. The same approach is applicable in a wider sense when addressing the challenges posed by climate change.

Sustainable practices like conservation agriculture can keep carbon fixed. Conservation agriculture is a system of farming that conserves, improves and makes more efficient use of natural resources through integrated management of available soil water and biological resources. The reduced till agriculture advocated by conservative agriculture means more carbon can remain trapped in the soil instead of being released when the soil is ploughed

extensively before each planting. Important interventions include proper land preparation to minimize soil erosion, making contours and water channels to maximize water use, keeping overall water use low. Micro irrigation and drip irrigation are effective but expensive. Other helpful actions are planting trees and fodder crops on contours and watersheds, agro forestry and reforestation, crop rotations, green manure crops and intercropping as well as mulching and keeping a cover of crop residues on the surface.

The drawback though is the necessity of controlling weeds by extensive use of chemicals. But it is possible to replace chemical fertilizers and pesticides with bioorganic nutrients as much as possible without compromising yield. Such an agriculture system needed not necessarily conform to the standards set for organic certification.

Replacing agrochemicals with bio-organic substitutes, leads to a significant reduction in the carbon footprint. Reducing the application of nitrogenous fertilizers like urea will have a great impact on nitrous oxide emissions. Barring areas like Punjab, Indian agriculture which is largely manual, as against the highly mechanized agriculture of the west, has a low carbon footprint because it does not use fossil fuels.

System of Rice Intensification

Some (relatively) new agronomic practices are showing promise as adaptive strategies and are yielding good results, particularly in rice cultivation, which is Asia’s main crop. The System of Rice Intensification (SRI) is a water saving, methane emission reducing rice cultivation strategy. Instead of flooding paddy fields as in current rice cultivation, the SRI consists of watering and draining the fields in a manner that significantly reduces the

amount of water required. Essentially, SRI changes agronomy practices in a manner that enables prolific root formation and tilling that leads to more panicles and hence more grains per plant. This has an obvious impact on raising crop yields. This strategy increases weeds in the fields which have to be dealt with but apart from reducing the use of water in crop production, SRI also reduces the build up of methane by doing away with standing water in rice paddies.

Agro biodiversity key to climate change adaptation

In addition to land and water, the other important factor needed to adapt to climate change, is the biodiversity related to agriculture that is adapted to local conditions. There is an urgent need to conserve the genetic diversity of crop plants and livestock. All the biodiversity related to agriculture is referred to as agro biodiversity and this according to the FAO, is acknowledged as a key resource to ensure that agriculture in various parts of the world can survive the onslaught of turbulent weather and unpredictable climate. Conserving agro biodiversity means conserving the gene pool and those genes that may come in useful for traits required by crops under changed conditions.

If coastal areas get submerged then crop varieties will need to develop tolerance to salinity and water logging. If on the other hand inland areas become drier and rain fed areas face almost drought like conditions, then it will be necessary develop crop varieties that are drought tolerant. Turbulence in the weather patterns including moisture and wind could bring new diseases and insect pests, requiring varieties that are resistant to these.

The key to breeding suitable varieties is to have access to the required genes, which would confer disease resistance or drought tolerance. Conserving agro biodiversity today

conserves genes for today and tomorrow.

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