Climate change & ecology: A relook into soil and water management

Citation: Sen, H.S. (2009). Soil and water management research - A relook vis-a-vis ecology and climate change. Journal of Indian Society of Soil Science, Vol 57(4):398-411

Invited Article

Soil and Water Management Research – A Relook vis-à-vis Ecology and Climate Change

H.S. SEN

Former Director, Central Research Institute for Jute & Allied Fibres (ICAR),

Barrackpore, Kolkata 700 120

Abstract: It is unequivocal that the climate change taking place worldwide constitutes a tangible risk to human society towards its development and sustainability, in other words, the ecology. Ecology and climate change, which are complementary to each other, are, in turn, influenced by societal activities including agricultural practices. The principal cause of climate change has been endorsed to global warming and therefore calls for a coordinated global response towards mitigation and adaptation in a warmer planet. Earth’s temperature is on the rise, as evident from the 11 warmest years out of 12 years between 1995 and 2006 with 0.74°C increase recorded between 1906 and 2005. Increased level of greenhouse gases (GHG), such as carbon dioxide, nitrous oxide, methane and carbon monoxide, has led to the global warming. Projected scenarios of global warming indicate that the global average surface temperature could rise by 0.3 to 6.4°C by 2100. The projected rate of warming has been unprecedented over the last 10,000 years. Global mean sea level is projected to rise by 0.18 to 0.59 m by the end of current century. Uncontrolled human activities, such as irrational agriculture, burning of fossil fuels, changed land use patterns and related practices are the major sources of GHGs. Gross per capita water availability in India will decline from 1820 m³ yr^-1 in 2001 to as low as 1140 m³ yr^-1 in 2050. Worldwide, the net effect of climate change will be to decrease stocks of organic carbon (C) in soils, thus releasing additional carbon dioxide (CO₂) into the atmosphere and acting as a positive feedback, further accelerating climate change. Soil managers, therefore, are ordained with the dual task of chalking up adaptation measures for maintaining organic carbon stock on one hand and formulate practices that would not furtherance climate change while water managers have to devise adept policies to secure water for food security in the face of global warming induced water scarcity in near and distant future. The present paper is an attempt to relook and suggest adaptation and mitigation options in soil and water management vis-à-vis changing ecology and climate with special reference to India.

Keywords: Climate & ecology change, GHGs, Global warming, Soil and water adaptation & mitigation strategies, Organic carbon, Carbon sequestration

Corresponding address: Dr. H. S. Sen, 2/74, Naktala, Kolkata-700047, West Bengal, India,

Email: hssen.india@gmail.com, hssen2000@hotmail.com

“Man, despite all his artistic pretensions, all his sophistications and all his accomplishments beyond count, cannot but owe his existence to a six inch layer on top of this earth and the fact that it rains…. (Unknown).”

Indeed it is. It is soil-based agriculture aided by water that has secured food for his hungry mouth from the inception of civilization. So, everything else apart, we are to manage our soil and water in a well thought out and prudent manner in order that our right to live may not be questioned. In our endeavour to secure more than is actually needed we have over exploited these two precious resources. The situation has worsened in view of the cosmic rate of population increase. Coupled with this population increase, another grey area that human race has to confront is changing climate and ecology, complimentary to each other, which is pressurising our agriculture in a complex manner than ever before. It has been commonly believed that developing countries, like India, are more susceptible to climate change because of their reliance on low-capital agriculture. It is hypothised that low-capital agriculture would be more onerous to adapt to climate changes. Agronomic studies on crop yield reductions support this wisdom implying large potential agricultural damages in India, for example (Dinar et al. 1998).

In the extreme eagerness to produce more, we have sapped our soils of its’ verve by this high input, highly intensive agriculture in the name of Green Revolution, notwithstanding the alarming depletion in soil organic carbon and secondary nutrient induced by major nutrients, notwithstanding the increasing production of major greenhouse gases and the enhancing contamination of groundwater. So severe is the degree that agriculture is largely becoming a non-point source of environmental pollution. Agriculture has now a definable role in change in ecology and climate throughout the world. Rainfall becoming erratic, seasons are either prolonging or shortening, storms/ cyclones are increasing, sea level is rising and these phenomena, collectively, are eating out our two most precious resources – soil and water. Simply put we have gone against Nature and now the Nature is retaliating.

It is unequivocal that the climate change taking place worldwide constitutes a tangible risk to human society towards its development and sustainability, in other words, the ecology. Ecology and climate change are, in turn, influenced by societal activities including agricultural practices. The present paper makes an attempt to relook and suggest adaptation and mitigation options in soil and water management vis-à-vis changing ecology and climate with special reference to India.

Present scenario of Indian agriculture

Indian agriculture is challenged. India harbours 17% of global population in only 2.3% land mass supported by 4% of fresh water resources. Naturally, maintenance of food and water security for all its’ people is more arduous than any other countries. There is no denying the fact that the net cultivable area in the country of around 140 Mha is remaining constant or even squeezing from the pressures of urbanization, industrialization, infrastructure development and to house the ever increasing populace. Then loss of productive soil is another concern. Around 5 billion tonnes of soil is washed away every year taking away with it nearly 6 million tonnes of nutrients due to ill soil and water management practices. Emphasis on application of major nutrients has triggered widespread deficiencies of secondary and micronutrients like sulphur (41%), zinc (49%), boron (33%) with other micronutrients, e.g. iron, copper, manganese, molybdenum deficiencies are on the rise (Singh 2009). The water scenario is equally grisly. Per capita availability of water has radically reduced from over 5000 m³ in the 50’s to a meagre 1656 m³ in 2007 and is conjectured to be well less than the internationally prescribed level (1700 m³) to 1140 m³ by 2050. Currently almost 80% of this water is generally allocated to agriculture, but in all likelihood it could be cut down by 10-15% due to challenges from other sectors like domestic, industry, power, etc. Population is another issue that needs to be addressed vis-à-vis precise soil and water management for ensuring food security. Having considered all these, crop production is surmised to increase at a rate of 4% in the coming decades which is only possible if we are able to manage our soil and water judiciously in the face of changing climate induced soil and water ecology.

Climate change – Present status and future implications

The Intergovernmental Panel on Climate Change (IPCC) defines climate change as a movement in the climate system because of internal changes within the climate system or through the interaction of its components, or because of changes in external forces either by natural factors or anthropogenic activities (IPCC 1996).

Present status

The Intergovernmental Panel on Climate Change (IPCC) concluded that worldwide, agriculture exacerbates climate change trends by contributing about 13.5 percent of global GHG emissions (Cline 2007). Contribution of agricultural activities towards CH₄ and N₂O emission is shown in Fig. 1.

	Fig. 1. Agricultural greenhouse gas emissions, average from 2001 to 2005. (Source: EPA 2007)

Direct and indirect determination of CO₂, CH₄ and N₂O in the atmosphere over the past 1000 years show marked and unprecedented increases in concentrations in recent times. The start of these increases coincides with the rapid industrialization of the Northern Hemisphere. During the late eighteenth and nineteenth centuries the global mean atmospheric concentration of CO₂ has increased by 31%; approximately 75% of this increase has come from fossil fuel combustion and 25% from land use change (IPCC 2001).

Projections & Future implications

Implications of climate change on agriculture is huge pertaining to the fact that climate change is, and likely to, make perceptible alterations in temperature, precipitation and solar output, the three most critical climatic variables in crop growth, enough to hamper crop production. The carbon dioxide concentration is increasing by 1.9 ppm each year and is expected to reach 550 ppm by 2050 and 700 ppm by 2100. Apart from the long durational changes, seasonal changes in above three variables are very likely. Seasons are either prolonging or shortening or retreating. This is affecting, and will be affecting more, the cropping potential or performance of land. For example, in Alberta (Canada) the potential maize-growing zone has shifted north by 200–300 km over the last century (Shen et al. 2005). Another study indicates that start of spring is advancing by 2 days per decade (Parmesan and Yohe 2003). This may have telling effect on winter wheat. A study by IARI indicates that every 1⁰C increase in temperature reduces wheat production by 4- 5 million tons in India. Dinar et al. (1998) used the output from GISS, UKMO and GFDL models in making projections of CO₂ – induced future seasonal changes in temperature and precipitation in India which reveals that doubling of atmospheric CO₂ is going to make noteworthy modification in the two parameters (Fig. 2). Climate changes are also likely to be accompanied by changes in crop management, as farmers adapt their management practices to the new climate (Southworth et al. 2000, 2002; Pfeifer and Habeck 2002; Pfeifer et al. 2002). For instance, decreased crop yields may lead the farmer to plant a new crop, or farmers may change planting dates of maize to take advantage of increased warmth or to avoid high temperatures during silking.

Soil vis-à-vis climate change

Climate change is taking place not due to current level of GHG emissions, but as a result of the cumulative impact of accumulated GHGs in the planetary atmosphere. Current emissions are, of course, adding to the problem incrementally. Even if current emissions were, by some miracle, reduced to zero tomorrow, climate change will continue to take place. This scenario seems utopian, as industry has to flourish for the need of civilization. So, climate change is, and will be, influencing agriculture. This necessitates plant breeders to find avenues to negate climate change effects on crop production either by developing GM crops suitable for cultivation under changing climate or through breaking thermo-sensitivity in principal cereals crops of rice and wheat or through other means while soil researchers are to concentrate on soil

Fig. 2. Simulation from UKMO, GISS and GFDL models on seasonal changes in temperature and precipitation under doubling of CO2 (Source: Dinar et al. 1998) ecipitation under doubling of CO2 (Source: Dinar, 1998)

management options that would not augment further GHG emission thereby inducing climate change since agricultural soil management is the chief contributor to GHG emission. Livestock industry also has a role to play but this is beyond the scope of this paper.

Soil organic matter

Soil organic matter is the elixir of life, particularly plant life, as it binds nutrients to the soil, thus ensuring their availability to plants. It is the home for soil organisms, from bacteria to worms and insects, and allows them to transform plant residues, and hold on to nutrients that can be taken up by plants and crops. It also maintains soil structure, thereby improving water infiltration, decreasing evaporation, increasing water holding capacity, and avoiding soil compaction. In addition, soil organic matter accelerates the break down of pollutants and can bind them to its particles, so reducing the risk of run-off.

Worldwide, the net effect of climate change will be to decrease stocks of organic carbon (C) in soils, thus releasing additional carbon dioxide (CO₂) into the atmosphere and acting as a positive feedback, further accelerating climate change. Atmospheric carbon maintains a balance with soil carbon through terrestrial ecosystem, especially forestry and agriculture (Fig. 3). Anthopogenic perturbations like deforestation, intense farming is tilting that balance. We, the soil researchers, are ordained to examine thoroughly if and where soil organic matter is declining throughout our territories, then to establish approaches to redress the situation and to implement these approaches so that soil not only retains its organic matter, but – wherever possible – becomes a sink for more carbon and therefore contributes to the fight against global warming.

	Fig. 3. Carbon pools in forestry and agriculture. (Source: EPA 2008)

Adaptation and mitigation

(i) Carbon sequestration- Locking up atmospheric carbon:

We are fortunate in the sense that through proper management we can put back much of the SOC lost (Lal et al. 1998). Soil carbon sequestration is the process of transferring carbon dioxide from the atmosphere into the soil through crop residues and other organic solids, and in a form that is not immediately reemitted. This transfer or “sequestering” of carbon helps off-set emissions from fossil fuel combustion and other carbon-emitting activities while enhancing soil quality and long-term agronomic productivity. CO₂ is absorbed by trees, plants and crops through photosynthesis and stored as carbon in biomass in tree trunks, branches, foliage and roots and soils (EPA 2008). Forests and stable grasslands are referred to as carbon sinks because they can store large amounts of carbon in their vegetation and root systems for long periods of time. Soils are the largest terrestrial sink for carbon on the planet. The ability of agriculture lands to store or sequester carbon depends on several factors, including climate, soil type, type of crop or vegetation cover and management practices.

(ii) Minimum or no tillage:

In minimum or no-till agriculture (NT or no-till), soil carbon emissions are meant to be reduced by not disturbing the soil through tillage. There are different forms of this practice, but the dominant method is to sow (or drill) the seeds into the residues for the previous crop, and to deal with weeds through the application of herbicides. To date there are only estimates of how much carbon is sequestered in the soil in NT systems, and how this interacts with other factors, like soil respiration, N₂O emissions and denitrification.

(iii) Biochar:

Fig. 4. Biochar can result in a net removal of carbon from the atmosphere, especially with enhanced net primary productivity (Source: Sohi et al. 2009)

A number of studies have now highlighted the net benefit of using biochar in terms of mitigating global warming and as an active strategy to manage soil health and productivity (Ogawa et al. 2006). Biochar is a fine-grained and porous substance, similar in its appearance to charcoal produced by natural burning. Biochar is produced by the combustion of biomass under oxygen-limited conditions (Fig. 4). Biochar is proposed as a new form of soil carbon sequestration in which fine-ground charcoal is applied to the soil. International Biochar Initiative (IBI) argues that applying charcoal to soils would create a reliable and permanent carbon sink, and would mitigate climate change, as well as making soils more fertile and water retentive.

(iv) Incorporation of crop residue:

Another major contributor of GHGs is the burning of crop residues. In Punjab, wheat crop residue from 5,500 square kilometers and paddy crop residues from 12,685 square kilometers are burnt each year. Every 4 tons of rice or wheat grain produces about 6 tons of straw. Emission Factors for wheat residue burning are estimated as: CO₂- 34.66 g kg^-1, NO_x – 2.63 g kg^-1, CH₄ – 0.41 g kg^-1 (Ramanjaneyulu 2006). Incorporation of residue not only minimizes GHG emission but takes care of soil carbon.

(v) Mitigating nitrous oxide emission:

N₂O comes from two main sources—livestock manure and chemical fertilizers. In dairy and cattle operations, large amounts of ammonia are produced when urea and livestock manure break down in water or slurry. Even greater emissions come from field operations, where applications of nitrogen fertilizer and related cropping practices constituted 68 percent of U.S. nitrous oxide emissions in 2004 (Anon 2006). Since fertilizer is responsible for large amounts of agricultural sector N₂O emissions, farmers can choose to implement soil management practices that lead to appropriate fertilizer application rates. One of these practices is nitrogen field testing, which determines the nitrogen fertilizer needs of a crop Farmers who use these simple tests can decrease N₂O emissions by avoiding costly fertilizer over-application that results from following many of the recommended application rates based on ideal growing conditions. In addition to nitrogen field sampling, further N₂O mitigation options include using cattle feed pads during winter months, using nitrification inhibitors with fertilizer, properly timing fertilizer applications, improving field drainage, and avoiding soil compaction which slows water drainage.

(vi) Mitigating methane emission:

Besides factors like enteric fermentation in digestive systems of cattle, anaerobic decomposition of animal waste, rice production is also responsible for the CH₄ emissions from agriculture. These emissions are generated through the cultivation of wet rice, which promotes the anaerobic decomposition of plant wastes that remain after harvest. A large part of our country practises traditional rice farming and as such risk of CH₄ emission from these submerged soils is huge. System of rice intensification can be a way out of this problem since it follows alternate wetting and drying which besides taking care of CH₄ emission augers well for future food security (Prasad 2006a).

(vii) Organic farming systems:

Recent reports have investigated the potential of organic agriculture to reduce greenhouse gas emissions (Anon 2008). Organic systems of production increase soil organic matter levels through the use of composted animal manures and cover crops. Organic cropping systems also eliminate the emissions from the production and transportation of synthetic fertilizers. Components of organic agriculture could be implemented with other sustainable farming systems, such as conservation tillage, to further increase climate change mitigation potential.

(viii) Land restoration and land use changes:

Land restoration and land use changes that encourage the conservation and improvement of soil, water and air quality typically reduce greenhouse gas emissions. Modifications to grazing practices, such as implementing sustainable stocking rates, rotational grazing and seasonal use of rangeland, can lead to greenhouse gas reductions. Converting marginal cropland to trees or grass or bioenergy crops can significantly maximizes carbon storage on land that is less suitable for crops.

(ix) Soil water management:

Improvements in water use efficiency through measures, such as advanced irrigation systems, viz. drip irrigation technologies; center-pivot irrigation systems, etc. coupled with reduction in operating hours, can significantly reduce the amount of water and nitrogen applied to the cropping system. This reduces greenhouse emissions of nitrous oxide and water withdrawals.

(x) Increasing fertilizer use efficiency:

Improving fertilizer efficiency through practices like precision farming using GPS tracking can reduce nitrous oxide emissions. Other strategies include the use of cover crops and manures (both green and animal), nitrogen-fixing crop rotations, composting and compost teas, and integrated pest management, etc.

(xi) Checking on soil erosion:

Fig. 5. Effects of climate change on soil and water (Source: Anon 2003)

The potential for climate change—as expressed in changed precipitation regimes—to increase the risk of soil erosion, surface runoff, and related environmental consequences is clear. Effect of climate change on soil and water resources in shown in Fig 5. Erosion and runoff can lead to water pollution as well. Increases in soil losses were sometimes associated with increased precipitation, and sometimes more likely associated with decreased crop cover from lowered maize yields, brought about by extreme heat or drought under climate change. Planting date changes had an additional effect on erosion, e.g. later planting dates for maize increased soil loss. Suitable rotation of crop can deal with this issue substantially (O’Neal et al. 2005).

(xii) Better soil health:

Of the range of potential indicators used to infer soil health status, soil carbon is particularly important (Burke et al. 1989; Dalal and Chan 2001). Organic matter provides an energy source for microbes, structurally stabilizes soil particles, stores and supplies essential plant nutrients, such as nitrogen, phosphorus and sulphur, and provides cation/ anion exchange for retention of ions and nutrients (Muckel and Mausbach 1996). Carbon within the terrestrial biosphere can also behave either as a source or a sink for atmospheric CO₂ depending on land management, thus potentially mitigating or accelerating the greenhouse effect (Lal 2004). Relationship between soil health and climate change is

shown

Fig. 6. Potential links between climate change and soil health (Source: Nuttal 2007)

in Fig. 6. Cycling of soil organic carbon is also strongly influenced by moisture and temperature, two factors which are predicted to change under global warming. Overall, climate change will shift the equilibrium, both directly and indirectly, of numerous soil processes. These include carbon and nitrogen cycling, acidification, risk of erosion, salinisation, all of which will impact on soil health.

Water vis-à-vis climate change

Fig. 7. Impact of human activities on freshwater resources and their management (Source: Kundzewicz et al. 2007)

Climate change impact on water resources is more stringent even than its’ impact on soil. Water is indispensable for all forms of life. Access to freshwater is now regarded as a universal human right, but the irony is that it is human activities which is pressurising freshwater resources hardest with climate change being one of the multiple pressures. Fig. 7 depicts the impacts of climate change on freshwater resources and their management.

The key findings of the Working Group II of IPCC as delineated in its Third Assessment Report are as follows:

• The effect of climate change on streamflow and groundwater recharge varies regionally, largely following projected changes in precipitation.

• Peak streamflow is likely to move from spring to winter in many areas due to early snowmelt, with lower flows in summer and autumn.

• Glacier retreat is likely to continue, and many small glaciers may disappear.

• Generally, water quality is likely to be degraded by higher water temperatures.

• Flood magnitude and frequency are likely to increase in most regions, and volumes of low flows are likely to decrease in many regions.

• Globally, demand for water is increasing as a result of population growth and economic development, but is falling in some countries, due to greater water use efficiency.

Fig. 8. Effect of greenhouse gases and global warming on the hydrologic cycle (Source: Trenberth 1999)

GHGs emitted due to anthropogenic activities and associated global warming is augmenting changes in hydrologic cycle (Fig. 8). A warmer climate will accelerate the hydrologic cycle, altering rainfall, magnitude and timing of runoff. Warm air holds more moisture and increase evaporation of surface moisture. With more moisture in the atmosphere, rainfall and snowfall

events tend to be more intense, increasing the potential for floods (Mall et al. 2006).

Indian scenario

Although India is endowed with as many as 12 major rivers with a catchment area of 252 Mha, the enormous populace is pressurising its water resources. Fig. 9 shows the observed and projected decline in per capita average annual freshwater availability and growth of population from 1951 to 2050. This clearly indicates the ‘two-sided’ effect on water resources – the rise in population will increase the demand for water leading to faster withdrawal of water and this in turn would reduce the recharging time of the water-tables. As a result, availability of water is bound to reach critical levels sooner or later. The upper Gangetic plain is already under economic water scarcity. The snow line and glacier boundaries are sensitive to changes in climatic conditions. Almost 67% of the glaciers in the Himalayan mountain ranges have retreated in the past decade. Available records suggest that the Gangotri glacier is retreating about 28 m per year. A warming is likely to increase the melting more rapidly than the accumulation. Glacial melt is expected to increase under changed climate conditions, which would lead to increased summer flows in some river systems for a few decades, followed by a reduction in flow as the glaciers disappear (IPCC 2001).

The enhanced surface warming over the Indian subcontinent by the end of next century would result in increased pre-monsoonal and monsoonal rainfall over the coastal plains, increased annual runoff in the central plains, with no substantial changes in winter runoff, and increase in soil evaporation and soil wetness during the monsoon and on an annual basis (Lal and Chander 1993).

Agriculture accounts for the major share of water use in all countries and especially in India. At present Indian agriculture accounts for nearly 80% of total water use which is likely to be reduced to about 68% in 2050 due to competition from other sectors like domestic, power, industry, etc. Another notable point is that global warming is likely to increase evaporation loss 7 fold, from 1% to about 7% in 2050 (Fig. 10).

	Fig. 10. Projected water resource availability for different uses (Adapted from: Mall et al. 2006)

Under such circumstances agricultural water management assumes key importance in managing water for future water security in India.

Adaptations

A. Agricultural water management

Agricultural water management permits concentration of inputs and provides stability of supply of many agricultural products. While only responsible for some 40% of agricultural production, this stability of supply buffers the volatility of rainfed production and therefore a key factor in market-driven agriculture (FAO 2008).

(i) Increasing water use efficiencies:

Increasing water use efficiencies of different crops can counter water scarcity in a big way. Rice and wheat are the principal foodgrain crops of India and the world. Water requirement for rice itself is nearly 80% of total agricultural water requirement and rice-wheat together accounts for well over 90% of it. FAO estimates in 100 countries reveal that of 230 Mha irrigated harvested area rice and wheat covers 130 Mha. So adoption of water use efficient cultivation practices for rice, wheat and other crops can substantially reduce requirement load of water for agriculture.

(ii) System of rice intensification (SRI):

This is one technique of rice growing which is gaining popularity, especially in the developing countries. Water use for 1 kg of rice production is between 1800 – 3000 litre (De Dutta 1981), which can be reduced to 800 – 1500 litre by this method of rice cultivation as this system advocates alternate wetting and drying along with other modified management practices resulting in enhanced produce (Ceesay 2002; McDonald et al. 2006; Prasad 2006b), especially in developing countries (Table 1).

(iii) Zero tillage:

Growing crops using zero or minimum tillage, apart from restricting CO₂ emission, is also water use friendly and is being propagated worldwide. Sowing wheat through zero-till seed drill and applying one irrigation at CRI stage has been found to be efficient and cost-effective in wheat (Anon 2007).

(iv) Paira cropping for oilseed and pulsed crops:

Paira cropping is another water use efficient technique for growing oilseed and pulse crops. Rice-oilseed and rice-pulse are two major cropping patterns of India. Sowing oilseeds or pulses in the residual moisture 10 days before harvesting rice has been effective in producing comparable yields besides being useful regarding water and time management (Ali and Mishra 2004).

Table 1. Increments in yield (t ha^-1) due to SRI over

conventional rice farming (Source: Uphoff 2005)

­Country	Conventional	SRI	% increase
Gambia	2.3	7.1	209%
Madagascar	2.6	7.2	177%
Myanmar	2.0	5.4	169%
Sri Lanka	3.6	7.8	116%
Sierra Leone	2.5	5.3	112%
Nepal	4.2	8.5	102%
India	4.0	8.0	100%
Cambodia	2.7	4.8	78%
Cuba	6.2	9.8	58%
Indonesia	5.0	7.4	37%
Bangladesh	4.9	6.3	29%
China	10.9	12.4	14%

(v) Conservation of soil moisture:

Conventional soil moisture conserving methodologies like mulching are useful in view of future water scarcity. There is need for these technologies to be assessed and fine-tuned to become cost-efficient and location-specific before transferring to farmers’ fields. Cross-linked polymers of acrylic acid and acrylamides have been found handy in conserving soil moisture and can be propagated for wider use.

B. Rainwater harvesting

Although globally, mean precipitation is projected to increase due to climate change, variability in rainfall will be more. Some season will get more rain and some will less (Kundzewicz et al. 2007). This is going to hamper the location-specific conventional crop growing. It is estimated that only 4.5 % of rainwater is used for rainfed cultivation while only 2 % of the total rainwater is used for irrigated agriculture mainly by withdrawing water from the underground. The colossal loss of 36 % water holds the key to create higher storage opportunities by reducing the runoff losses. Creation of suitable on-farm reservoirs (OFR) wherever possible can serve the purpose of water security for agriculture in near and distant future.

C. Integrated water resource management

Integrated Water Resources Management should be an instrument to explore adaptation measures to climate change, but so far is at its infancy. Successful integrated water management strategies include, among others: capturing society’s views, reshaping planning processes, coordinating land and water resources management, recognizing water quantity and quality linkages, conjunctive use of surface water and groundwater, protecting and restoring natural systems, and including consideration of climate change.

Integrated water management for coastal regions:

Coastal areas are more vulnerable to climate change than any other regions due to the fact that rising seawater will ingress into more coastal plains in future which apart from constraining agriculture and aquaculture will influence livelihood security in a big way. In view of the susceptibility of the coastal plains to seawater intrusion and its adverse impact on soil and plant growth, the practice for use of ground water, even if in small quantity, for irrigation should be very carefully exercised, for which suitable optimization model may be used. It should not be difficult to avoid using the underground water, if properly planned, by increasing the surface storage of runoff water by an equivalent amount or more. Thus, water management in the coastal plains should principally revolve round creating more fresh surface water sources and their proper management with little dependence on the subsurface source in order to maintain stability of the ecosystem.

Future research needs

:

Soil

• GCMs should be carefully devised for each agro-ecological zones.

• Soil carbon being the single most important crop growth parameter, simulation studies on soil carbon dynamics in enhanced GHG scenarios need to be done.

• Change in other nutrient dynamics should be studied with greater precision, say using isotopic techniques.

• More effective techniques for sequestering soil carbon need to be devised.

• Social, economic and environmental suitability of diversification with bio-energy crops should be properly assessed.

• Economic feasibility and social acceptability of organic farming systems should be assessed.

• Focus on monitoring soil properties should be applied in terms of soil health; and GoI should introduce ‘soil health card’ in place of ‘soil fertility card’ as currently under practice.

Water

• There is a mismatch between the large-scale models on climate and catchment, which needs further resolution.

• Impacts of changes in climate variability need to be integrated into impact modeling efforts on hydrology and water management.

• Improvements in coupling climate models with the land-use change, including vegetation change and anthropogenic activities including irrigation and water management, are necessary.

• Climate change impacts on water quality are poorly understood. There is a strong need for enhancing research in this area.

• Despite its significance, groundwater has received little attention from climate change impact assessments, compared to surface water resources, which should be re-enforced.

• Water resources management clearly impacts on many other policy areas (e.g., energy projections, nature conservation, etc.). Hence there is an opportunity to align adaptation measures across different sectors.

Epilogue

Our climate is changing and changing faster than we are changing ourselves. Capital-intensive agriculture in the developed countries is fast augmenting this change, while low-capital agriculture in the developing and under-developed countries is at receiving end. Given the fact that man cannot dictate over the external or natural factors of climate change to a significant extent, he can at best put a check on the internal ones which are basically anthropogenic through timely adaptation and mitigation. Soil and water are the resources that mankind has relied and will be relying for survival and as such soil and water managers are bestowed with the responsibility to manage these two resources in thoughtfully cautious yet optimally productive way to ensure food security for the generation-next. Temperature and precipitation are the prime climate regulated phenomena, and will be influencing these two resources in the long run. Projections from GCMs indicate an increase in temperature of 0.3⁰ to 6.4⁰ by the end of this century which will lead to much enhanced evapotranspiration and therefore increased water requirement for crops. Total precipitation worldwide is projected to increase, and along with it the spatial and temporal variability is also likely to increase, which will adversely affect the conventional seasonal cropping practices.

This invokes adaptation and mitigation measures. While water management has relatively little role to mitigate climate change, soil has a colossal role through adaptation measures like carbon sequestration, organic agriculture, land use changes, improved management practices. In case of water, adaptation is required in view of enhanced future water demand and less freshwater water availability as a result of competition from other sectors. Improving water use efficiencies, meaningful conservation and utilization of soil moisture, rainwater harvesting and integrated water resource management can serve the purpose to a great deal and as John Holdren, President of the American Association for the Advancement of Science, says, “We basically have three choices – mitigation, adaptation, and suffering. The more mitigation we do, the less adaptation will be required, and the less suffering there will be.”

In essence, we bear the responsibility ”…to bequeath to our children a world which is safe, clean and productive, a world which should continue to inspire the human imagination with the immensity of the blue ocean, the loftiness of snow-covered mountains, the green expanse of extensive forests and the silver streams of ancient rivers” (Prime Minister Dr. Manmohan Singh in ‘The Road to Copenhagen: India’s position on Climate Change Issue’, Public Diplomacy Division, Ministry of External affairs, Govt. of India) and to secure all our people enough clean food and water. We have to keep these in mind while aligning ourselves in future soil and water management research. Ours is a farmer- and farming- dominated country where well being of the nation depends on well being of the farmers. As such agriculture is being advocated and actually is shifting to agribusiness, but that must not be at the cost of over-utilization of soil and water. We have to put constant vigil to ensure that agribusiness is done on need-base and not on greed-base for we must remember what one of the greatest statesman of contemporary era walked on this country once said,

“The world has enough to provide for one’s need, but not for one’s greed” (Mohandas K. Gandhi).

Acknowledgement

The author is profusely grateful to Mr.Dipankar Ghorai, SMS, KVK Burdwan for his untiring help and assistance in preparing the manuscript.

References

Ali, M. and Mishra, P. (2004) Rabi pulses. In: “Textbook of Field Crops Production”, Ed. R. Prasad, Indian Council of Agricultural Research, New Delhi, pp. 317-371.

Anon (2003) Conservation implications of climate change. In: “Soil Erosion and Runoff from Crop Land”, A report of Soil and Water Conservation Society, Iwoa, USA.

Anon (2006) In: “Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2004”, United States Environmental Protection Agency, Washington, DC, U.S.

Anon (2007) In: “DWR Perspective Plan: Vision 2025”, Directorate of Wheat Research, Karnal-132 001, Haryana, India.

Anon (2008) In: “Regenerative Organic Farming: A Solution to Global Warming”, Rodale Institute.

Burke, I.C., Yonker, C.M., Parton, W.J., Cole, C.V., Flach, K. and Schimel, D.S. (1989) Texture, climate, and cultivation effects on soil organic matter content. Soil Science Society of America Journal 53, 800-805.

Ceesay, M. (2002) Experiments with the System of Rice Intensification in the Gambia. In: “Assessments of the System of Rice Intensification”, Eds. N. Uphoff et al., pp. 56-57.

De Datta, S.K. (1981) In: “Principles and Practices of Rice Production”, John Wiley & Sons, New York.

McDonald, A.J., Hobbs, P.R. and Riha, S.J. (2006) Does the system of rice intensification outperform conventional best management? A synopsis of the empirical record. Field Crops Research 96, 31-36.

Cline, W.R. (2007) In: “Global Warming and Agriculture”, Center for Global development, Peterson Institute for International Economics, Washington DC.

Dalal, R. and Chan, K.Y. (2001) Soil organic matter in rainfed cropping systems of the Australian cereal belt. Australian Journal of Soil Research 39, 435-464.

Dinar, A., Mendelsohn, R., Evenson, R., Parikh, J., Sanghi, A., Kumar, K., McKinsey, J. and Lonergan, S. (1998) In: “Measuring the Impact of Climate Change on Indian Agriculture”, World Bank Technical Paper No. 402.

EPA (2007) In: “Inventory Report, April 2007” (www.epa.gov/climatechange/emissions/ usinventoryreport.html)

EPA (2008) In: “Carbon Sequestration in Agriculture and Forestry” (www.epa.gov/sequestration/index.html)

FAO (2008) In: “Climate Change, Water and Food Security”, Technical Background Document from the Expert Consultation, held on 26 to 28 February, FAO, Rome.

IPCC (1996) In: “Climate Change 1995—The Science of Climate Change. Contribution of Group I to the Second Assessment Report on the Intergovernmental Panel on Climate Change”, Cambridge University Press, Cambridge, UK.

IPCC (2001) In: “Climate Change 2001: The Scientific Basis”, Eds. J.T. Houghton, Y. Ding, D.J. Griggs, M. Noguer, P.J. Van der Linden, X. Dai, K. Maskell and C.A. Johnson, Cambridge University Press, Cambridge, UK.

Kundzewicz, Z.W., Mata, L.J., Arnell, N.W., Döll, P., Kabat, P., Jiménez, B., Miller, K.A., Oki, T., Sen Z., and Shiklomanov, I.A. (2007) Freshwater resources and their management. In: “Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change”, Eds. M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Cambridge University Press, Cambridge, UK, pp. 173-210.

Lal, R. (2004) Soil carbon sequestration to mitigate climate change. Geoderma 123, 1-22.

Lal, M. and Chander, S. (1993) Potential impacts of greenhouse warming on the water resources of the Indian subcontinent. JEH 1(3), 3-13.

Lal. R., Kimble, J.M., Follett, R.F., and Cole, C.V. (1998) In: “The Potential of U.S. Cropland to Sequester Carbon and Mitigate the Greenhouse Effect”, Ann Arbor Press, Chelsea, MI.

Mall, R.K., Gupta, A., Singh, R. and Rathore, L.S. (2006) Water resources and climate change: An Indian perspective. Current Science 12, 90.

Muckel, G.B. and Mausbach, M.J. (1996) Soil quality information sheets. In: “Methods for Assessing Soil Quality”, Eds. J.W. Doran and A.J. Jones, Soil Science Society of America Inc, Wisconsin.

Nuttal, G.J. (2007) In: “Climate Change – Identifying the Impacts on Soil and Soil Health”, Department of Primary Industries, Horsham, Victoria, Australia.

Ogawa, M., Okimori, Y. and Takahashi, F. (2006) Carbon sequestration by carbonization of biomass and forestation: three case studies. Mitigation and Adaptation Strategies for Global Change 11, 429-444.

O’Neal, M.R., Nearing, M.A., Vining, R.C., Southworth, J. and Pfeifer, R.A. (2005) Climate change impacts on soil erosion in Midwest United States with changes in crop management. Catena 61, 165–184.

Parmesan, C. and Yohe, G. (2003) A globally coherent fingerprint of climate change impacts across natural systems. Nature 421 (6918), 37–42.

Pfeifer, R.A. and Habeck, M. (2002) Farm level economic impacts of climate change. In: “Effects of Climate Change and Variability on Agricultural Production Systems”, Eds. O.C Doering, J.C. Randolph, J. Southworth and R.A. Pfeifer, Kluwer Academic Publishers, Boston, pp. 159–178.

Pfeifer, R.A., Southworth, J., Doering, O.C., Moore, L. (2002) Climate variability impacts on farm-level risk. In: “Effects of Climate Change and Variability on Agricultural Production Systems”, Eds. O.C Doering, J.C. Randolph, J. Southworth and R.A. Pfeifer, Kluwer Academic Publishers, Boston, pp. 179–193.

Prasad, S. C. (2006a) In: “System of Rice Intensification in India Innovation History and Institutional Challenges”, Xavier Institute of Management, Bhubaneswar, Orissa.

Prasad, S. C. (2006b) In: “System of Rice Intensification in India: Innovation History and Institutional Challenges”, WWF-ICRISAT Dialogue on Water, Food and Environment, Patancheru, Hyderabad.

Ramanjaneyulu, G. V. (2006) In: “Sustaining Agriculture in the era of Climate Change in India”, Civil Society Position Paper, Centre for Sustainable Agriculture, Tarnaka, Secunderabad.

Singh, A. (2009) Development, conservation and utilization of soil resource – random thoughts. Newsletter, Indian Society of Soil Science, March No. 26.

Shen, S.S.P., Yin, H., Cannon, K., Howard, A., Chetner, S. and Karl, T.R. (2005) Temporal and spatial changes of the agroclimate in Alberta, Canada from 1901 to 2002. Journal of Applied Meteorology 44 (7), 1090–1105.

Sohi, S., Loez-Capel, E., Krull, E. and Bol, R. (2009) In: ”Biochar's Roles in Soil and Climate Change: A Review of Research Needs”, CSIRO Land and Water Science Report 05/09.

Southworth, J., Pfeifer, R.A. and Habeck, M. (2002) Crop modeling results under climate change for the upper Midwestern United States. In: “Effects of Climate Change and Variability on Agricultural Production Systems”, Eds. O.C Doering, J.C. Randolph, J. Southworth and R.A. Pfeifer, Kluwer Academic Publishers, Boston, pp. 127–158. Chapter 7.

Southworth, J., Randolph, J.C., Habeck, M., Doering, O.C., Pfeifer, R.A., Gangadhar Rao, D. and Johnston, J.J. (2000) Consequences of future climate change and changing climate variability on maize yields in the midwestern United States. Agriculture, Ecosystems and Environment 82, 139–158.

Trenberth, K. E. (1999) Conceptual framework for changes of extremes of the hydrological cycle with climate change. Climatic Change 42, 327-339.

Uphoff, N. (2005) The development of the System of Rice Intensification. In: “Participatory Research and Development for Sustainable Agriculture and Rural Development”, Eds. J. Gonsalves et al. 3, pp. 119-125, International Potato Center-UPWARD and International Development Research Centre, Ottawa.