Who is watching out for agriculture?

Suman Sahai

In a belated response to the challenges posed by climate change, India has finally prepared an action plan. The thrust of the National Action Plan on Climate Change, unveiled by the Prime Minister is on energy. The plan identifies eight core “national missions” running through 2017 and directs ministries to submit detailed implementation plans to the Prime Minister’s Council on Climate Change by December 2008. Not surprisingly, one of the weakest links in the Action Plan is its response to agriculture. Whereas market based incentives have been formulated for industry and affluent consumers, like automobile owners, not much is proposed to rescue farmers, who will be the worst affected category, standing perhaps, to lose their livelihoods. They and poor consumers are not visible in the national deliberations and have been left to cope on their own. This is demoralising specially when it has been projected by practically all the models generated by international teams of scientists, that South Asia will be amongst the worst affected areas impacted by global warming and would face serious challenges to food production.

In India, food security has still not been achieved on a sustained basis as we remain totally dependent on the monsoons to achieve food production targets. With its dependence on the monsoon and its low levels of irrigation, only a third of the country’s agriculture is irrigated, the rest being rain fed, the prospect of swings in the monsoon are a frightening possibility. Yet, little is being planned to cope with this situation, which is not in some distant future, but is upon us. The meteorological department’s linkage with agriculture departments remains a formality, when actually they should be working closely together to predict the onset of the rainy seasons and planning planting cycles according to that.

If the onset of the South-west monsoon is delayed, farmers can be told to delay planting their rice; if on the other hand, as we saw this year, the rains came very early, farmers could have been advised to plant another suitable crop. Swings in rainfall patterns are expected to intensify with climate change, so coordination between the Met department and agriculture departments will become even more crucial and necessary in future.

What is worrying though is that far from responding to the rapidly changing situation with any urgency, our system of agriculture research and implementation seems to be immobile and unable to cope. The Indian Council of Agriculture Research, India’s leading agency (some would say, leading in expenditure rather than competence) has still not revealed any plans on how it proposes to adapt to food production in a warming world. No strategies have been prepared, nor any changes in research strategies developed to address the impact of global warming on agriculture in the many agro climatic zones in the country.

Perhaps the most urgent requirement today is to anticipate how the crop cycle in each of the agro climatic zones will be affected by the predicted rise in temperatures. New crop varieties will be needed to plant in situations where the older crop varieties that were well adapted earlier, will not be so, when the conditions are warmer. Say for instance, the varieties of maize that are being cultivated in the mountain belt of Himachal Pradesh, will not perform well there when temperatures rise. New varieties of maize will have to be developed for that eventuality. Developing a new variety and testing its suitability for a region takes time.

It takes even more time to generate enough planting material like seeds or tubers to make available to farmers. An exercise begun today will yield results only in some years. Yet, the country’s agriculture research and implementation machinery sits inertly, unable to react either timely or appropriately.

Overhauling the ICAR has been on the cards for a long time. It is high time this exercise is undertaken and a new ICAR crafted to make it more responsive to the challenges that Indian agriculture is facing. Fresh blood needs to be inducted and a radical new approach and fresh plans are needed which include the perspectives and experience of a range of stakeholders who are seldom consulted in agriculture planning. These should include experts in diverse fields like water conservation, ecology, pest control, genetics and plant breeding working in formal institutions and in civil society organisations (CSOs).

Many groups working on the ground have valuable experiences and suggestions that should be heard. The indigenous knowledge of rural and tribal people must be tapped and combined with formal science to find solutions and to create new opportunities.

Climate Change and Agriculture : Reinventing the crop cycle

Suman Sahai

Increasing temperatures, shifting rain patterns and frequency of extreme weather spells threaten global food systems. The new buzz phrase is `climate proofing of crops'.

Global climate change, if it occurs, will definitely affect agriculture. However, simulation of crop response models has been limited to a few major crops for a region, usually important grain crops, with yield effects extended to other crops. Also, model responses do not take into consideration carbon dioxide or CO, fertilisation and improved water-use efficiency, the effect of cloud cover (on both climate and photosynthesis), or the uncertain nature of climate change. Farmers will have to change crop management practices, grow tougher plant varieties and be prepared for constant change in the way they operate. Temperature and rain are the key factors that affect crops.

Higher Temperatures

Crop-producing areas may expand northwards to ice-bound regions in Greenland, Canada and Russia. At higher latitudes, global warming will extend the length of the potential growing season, because the snow bound period will be reduced. This could allow earlier planting of crops and the possibility of taking two crops instead of just one crop as now. On the other hand crops adapted to the growing-season temperature and day lengths of the plains and lower latitudes may not respond well to the changed conditions. Satellite data shows that the dry trop-ics, where rainfed agriculture provides 60 per cent of the world's food, will be the most vulnerable to climate change.

In warmer, plains regions, increased temperatures may speed up the rate at which plants release carbon dioxide in the process of respiration, resulting in less than optimal conditions for net growth. When temperatures exceed the optimal for biological processes, plants will respond with a drop in yield. If minimum night-time temperatures rise significantly--as is expected from green-house warming projections, higher night-time respiration -may also reduce potential yields. Another important effect could be accelerated physiological development, resulting in premature maturation and, therefore, reduced yield. Increased temperatures may also lead to more decomposition of soil organic matter.

Increased Co2

Photosynthesis is the foundation of plant growth. It is the process by which the energy of sunlight converts water from the soil and carbon dioxide from the air into sugar, starches, and cellulose, making the plant grow. Carbon dioxide enters a plant through its leaves. Greater concentration of carbon dioxide in the air will result in higher carbon dioxide uptake and greater conversion to carbohydrates.

Crop species vary in their response to carbon dioxide. Wheat, rice, and soybeans arc called C3 plants and respond readily to increased carbon dioxide levels. Corn, sorghum, sugarcane, and millet arc C4 plants that follow a different pathway and arc more efficient photosynthetically than C3 crops. So far these distinctions have been demonstrated only under experimental conditions such as growth chambers and greenhouses. Experimental studies of the long-term effects of carbon dioxide in realistic field settings have not yet been done on a comprehensive scale.

Already; rising carbon dioxide levels arc changing the metabolism of grasses and shrubs on rangeland, decreasing the protein levels in plants eaten by cattle. Higher temperatures are already, resulting in shorter picking sea-sons.

Higher levels of atmospheric carbon dioxide also induce plants to close the small leaf openings known as stomata through which carbon dioxide is absorbed and water vapour is released. Thus, under higher carbon dioxide conditions, crops may use less water (by closing their stomata) even while they, produce more carbohydrates. This dual effect is likely to improve water-use efficiency, which is the ratio between crop biomass and the amount of water consumed. At the same time, climatic effects, such as higher temperatures and changes in rainfall and soil moisture, could either enhance or negate potentially beneficial effects of enhanced atmospheric carbon dioxide on crop physiology.

Water Stress

Climate change and global warming will modify rainfall, evaporation, surface runoff, and soil moisture storage. If temperatures and rainfall patterns turn adverse, soil mois­ture stress will result from increased evaporation from the soil and accelerated transpiration in the plants. Moisture stress during flowering, pollination, and grain-filling is harmful to almost all crops, but the most susceptible crops are corn, soybeans, and wheat, which are likely to suffer the worst damage when there is shortage of soil moisture. The predictable response to this eventuality is to develop crop varieties with greater drought tolerance, those that can withstand moisture stress.

More crop pests

Insect pests proliferate more readily in warmer climates since conditions fbr growth and multiplication are more favourable compared to cooler conditions. The incidence of other crop diseases like fungal and bacterial infections is also likely to increase if the climate gets warmer.

In temperate areas, longer growing seasons will ena­ble insects to complete a greater number of reproductive cycles during the spring, summer, and autumn. Warmer winter temperatures may also allow larvae to survive the winter in areas where they are now limited by cold, thus causing greater infestation during the following crop sea­son.

Storms and hurricanes and changed wind directions are likely to change the spread of both wind-borne pests and of the bacteria and fungi that are the agents of crop disease. Crop-pest interactions may shift as the timing of development stages in both hosts and pests is altered. Livestock diseases may be similarly affected.

Climate proofing

Climate change is making crop scientists review their research agenda. Until now, their main focus was on improving yields. But with successive Intergovernmental Panel on Climate Change (IPCC) reports warning that increased droughts and floods will shift crop systems, 'climate-proofing' of crops has become crucial. The Consultative Group on International Agricultural Research (CGIAR) institutes are now investigating how to make crops' more resilient to environment stresses. But efforts are hampered because few climate models predict changes for individual regions, making it difficult to predict how climate change will affect growth and yields of specific crops in each region.

More importantly, under changing climate conditions, farmers' past experience will be a less reliable predictor of what is to come. In many areas of the world, the necessary adjustments (such as substituting crops, introducing or intensifying irrigation, and modifying field operations such as tillage or pest control) may be too costly for many farmers to implement. These and other uncertainties must be taken into account explicitly in climate change impact studies.