1. Introduction:Agriculture is crucial for ensuring food, nutritional and livelihood security of India. It engages almost 2/3rd of the workforce in gainful employment and accounts for about 13% of India’s gross domestic product. The country is well-endowed with natural resources including land, water, vegetation and climate. However, almost 60% of country’s net cultivated area is rainfed and exposed to several abiotic and biotic stresses. Moreover, the land holdings of Indian farmers are small with more than 80% of Indian farmers being marginal and small. The farms are diverse, heterogeneous and unorganized. Providing food and nutritional security to the increasing population is a major challenge for Indian agriculture. One of the causes of increasing concentration of greenhouse gases (GHGs) in the atmosphere being agriculture, India faces the twin challenges of increasing agricultural production to feed its growing population and containing emission of GHGs and thereby protecting agriculture from the adverse impacts of climate change. Therefore, the sustainable management of crop, soil and water is crucial for food and nutritional security of the country in the context of climate change. The ICAR-Indian Agricultural Research Institute (IARI), New Delhi has initiated timely action to address the problems of climate change. These efforts have provided valuable inputs in terms of impacts of climate change on major food crops and helped in developing adaptation and mitigation strategies for climate resilient agriculture. This publication highlights the salient achievements on climate change research at IARI. It provides specific information on the impacts and vulnerability of Indian agriculture to climate change, emission and mitigation of GHGs from agriculture, adaptation strategies for climate resilient agriculture, technology demonstration and capacity building activities, research facilities available for climate-research and salient publications brought out by the Institute on climate change and agriculture.
2. Impacts of climate change on Indian agriculture and projected adaptation gains: Climate change can affect agriculture through their direct and indirect effects on the crop, soil, water and pest. Increase in atmospheric carbon dioxide has a fertilization effect on crops with C3 photosynthetic pathway and thus promotes their growth and productivity. Increase in temperature can reduce crop duration, increase crop respiration rates, alter photosynthesis process, affect the survival and distributions of pest populations and thus developing new equilibrium between crops and pests, hastens nutrient mineralization in soils, decrease fertilizer use efficiencies, and increase in evapo-transpiration. Climate change also have considerable indirect effect on agricultural land use in India due to availability of irrigation water, frequency and intensity of inter- and intra-seasonal droughts and floods, soil organic matter transformations, soil erosion, changes in pest profiles, decline in arable areas due to submergence of coastal land, and availability of energy. Some of the salient findings of the Institute on the impacts of climate change are listed below.
2.1. Impacts on crop yield: • Climate change is projected to reduce irrigated rice yields by ~4% in 2025 (2010–2039) and rainfed rice yield by 6%. With adaptation, however, irrigated rice yields can be increased by about 17% and rainfed rice yield by about 20%. Rainfed rice yields in India to reduce by ~6% in the 2025 and <2.5 % in 2050 (2041-2070) and 2080 (2070-2099) scenarios.
• Wheat yield in India would reduce by 6 to 23% by 2025 and 2050 scenarios. Yield would be reduced in areas with mean seasonal maximum and minimum temperatures more than 27 and 13°C, respectively. Adjusting the time of sowing may be a practical low-cost adaptation.
• Mustard yield is projected to reduce by 2% in 2025 (2010–2039). Yield is projected to reduce in regions with current mean seasonal temperature regimes above 25/10°C during crop growth. As climatically suitable period for mustard cultivation may reduce in future, short-duration (<130 days) cultivars with 63% pod filling period will become more adaptable.
• The potato crop duration in the Indo-Gangetic Plains (IGP) is projected to decrease and yield is to reduce by ~2.5, ~6 and ~11% in 2025 (2010-2039), 2050 (2040-2069) and 2080 time periods. Change in planting time could be the most important adaptation option which may lead to yield gains by ~6% in 2020.
• Rainfed sorghum yield is projected to reduce by 2.5% in 2025 (2010-2039). Adaptation, however, can increase the productivity by 8% in 2025.
• Maize yield in kharif season is projected to decrease by 18% but adaptation can increase the yield upto 21%.
• Enhanced frequency and duration of extreme weather events such as flood, drought, cyclone, cold and heat wave may adversely affect agricultural productivity.
• However, rise in temperature may decrease cold waves and frost events leading to reduced frost damage to frost sensitive crops such as chickpea, mustard, potato and other vegetables in northern India.
• Studies using Open Top Chambers (OTC), Free Air Carbon dioxide (FACE) facility and Temperature Gradient Tunnels (TGT) showed that elevated CO2 increases whereas elevated temperature decreases biomass and grain yield of crops. Rice, chickpea and mustard crops showed greater thermal tolerance while wheat and groundnut were more thermo-sensitive and greengram and potato was moderate in thermal sensitivity.
2.2. Impacts on water : • Demand of irrigation water would increase with increased temperature and higher evapo-transpiration. This may also result in lowering of groundwater table in some regions.
• A significant increase in runoff is projected in the wet season that may lead to increase in frequency and duration of floods and also soil erosion. However, the excess water can be harvested for future use by expanding storage infrastructure.
• Water balance in different parts of India is predicted to be disturbed and the quality of groundwater along the coastal track will be more affected due to intrusion of sea water.
• Reduction in yield in the rainfed areas due to increased crop water demand and changes in rainfall pattern during monsoon season.
2.3. Impacts on soil: • Quantity and quality of organic matter content, which is already quite low in Indian soil, will further decline due to increased temperature.
• Increase of soil temperature will increase N mineralization but its availability may decrease due to increased gaseous losses through volatilization and denitrification.
• Change in rainfall volume and frequency and wind intensity may alter the severity, frequency and extent of soil degradation through erosion.
• Rise in sea level may lead to salt-water ingression in the coastal lands turning them less suitable for conventional agriculture.
• Under elevated CO2 concentration, crop residues may have higher C:N ratio, which may reduce their rate of decomposition and nutrient supply. Therefore, fertilizer recommendation and management needs to be modified when crop residues are incorporated in soil.
2.4. Impacts on pest: • There may be increase in agricultural insect and disease problems because of faster pathogen and vector development, rapid pathogen transmission and increased host susceptibility.
• There will be extension of geographical range, changes in population growth rates, alteration in relative abundance of pest species and increase in period of their activity. Besides, effectiveness of pest management tactics may also be adversely affected.
• It is projected that there will be changes in pathogen/insect-pest × host × environment interactions, and loss of resistance in cultivars containing temperature-sensitive genes.
• Emergence of new pest problems may take place with increased risk of invasion by migrant pest.
3. Vulnerability of Indian agriculture to climate change:•Vulnerability of Indian agriculture at the district level was assessed using three core components: (i) exposure to hazards, (ii) sensitivity to climate change i.e., the amount of damage expected to be caused by a particular event, and (iii) adaptive capacity to recover from stress using meteorological data for the period 1951-2010.
• Districts with high, medium and low vulnerability were classified in each state and detailed matrix on adaptation investments prepared.
• The districts located in the eastern and southern parts of Uttar Pradesh, state of Bihar, central Rajasthan and parts of north-east India are most vulnerable, whereas the districts in Punjab and Haryana are less vulnerable due to their higher adaptive capacity.
4. Emission and mitigation of greenhouse gases from Indian agriculture:
4.1. Emission of greenhouse gases: • Currently, the world emits about 50 billion tons CO2 eq., in which contribution of India was of about 5%. The energy sector in India contributes the highest amount GHGs (65%) followed by agriculture (18%) and industry (16%). Within agricultural sector, enteric fermentation i.e., emission from ruminant animals contributed the highest (56%) followed by soil (23%) and rice fields (18%). Burning of crop residues on-farmand manure management contributed 2% and 1% of the emission. The Institute has quantified GHGs emission from soils under cereals, millets, oilseeds,pulses and vegetables in northwest India.
• It was estimated that methane emission from Indian rice fields is about 3.5 million tons. This is the most rationalized estimate using the IPCC methodolgy with direct mesurements of methane emission from Indian rice fields. Among the various rice ecosystems, the highest emission was from the irrigated continuously flooded rice (34%), followed by rainfed flood-prone rice (18%) and irrigated single aeration (18%). Rainfed drought-prone, deep water and irrigated multiple aerations rice ecosystems contributed 16%, 8% and 6% of methane, respectively.
• The emission of nitrous oxide ranged from 0.5–2.0 kg ha-1. Fertilizer was the largest source contributing about 75-80% to the total nitrous oxide emission from Indian agriculture.
4.2. Trends in greenhouse gases emission: • During 1970 to 2014, the GHG emissions from Indian agriculture have increased by about 80%. The increased use of fertilizers and other agri-inputs and the rise in population of livestock are the major drivers for this increase in GHGs emissions. The relative contribution of Indian agriculture to the total GHGs emission from all the sectors of the country, however, has decreased from 33% in 1970 to 15% in 2014. A relatively faster growth and consequently higher emissions from the energy, industry and transport sectors vis-a-vis agricultural sector are responsible for the decrease in the relative contribution to GHGs from agriculture.
• From 1970 to 2014, the emission of CH4 from Indian rice fields has remained almost similar, though the rice production increased considerably. It is because of almost constant area under rice cultivation (43-44 Mha) and use of similar water and crop management practices by the farmers over the years. However, the emission of N2O has increased during this period because of the application of more N fertilizer in soil.
4.3. Mitigating greenhouse gases emission from agriculture: • Rice fields submerged under water are the potential source of CH4 production. Continuous submergence, higher organic C content and use of organic manure in puddled soil enhance methane emission. The strategies for mitigating methane emission from rice cultivation are promoting alternate wetting and drying; adopting direct-seeding of rice and system of rice intensification; improving organic matter management by promoting aerobic degradation through composting or incorporating it into soil during off-season drained period; and application of fermented manure like biogas slurry in place of unfermented farmyard manure.
• The Institute is working on identifying efficient microbes which can reduce GHGs emission from flooded rice and also improve rice growth.
• Options for reducing N2O emission from soil include application of N based on soil-test and leaf-colour chart, use of slow-release fertilizers and nitrification inhibitors such as neem-coated urea. These options, besides reducing emission have co-benefits such as cost savings, increased yields, improved soil health and pollution abatement.
• The Institute estimated that the C sequestration potential in the agricultural soils of the country is 300 to 600 million tons. Judicious nutrient management and use of organic manure and compost are crucial to soil organic C sequestration in Indian soils. Sequestraiton of C not only mitigates GHGs emission but also enhances soil productivity.
• The C sequestration potential of biochar has been studied in Inceptisol. The maize biochar with higher nutrient values especially N and P and C stability could be advocated for enhancing soil fertility and long-term C sequestration. Rice biochar might be advocated for higher microbial activities in restoring biological fertility of degraded soils.
• Conservation agriculture with zero tillage could be an efficient strategy for preserving soil organic carbon and enhancing soil health.
• The initiatives of the Govt. on promoting organic farming, soil health card and use of neem coated urea will help mitigating GHGs emisison.
5. Adaptation to climate change in Indian agriculture : Potential adaptation strategies to reduce the adverse impacts of climate change include developing cultivars tolerant to heat and moisture stresses, modifying crop management practices, improving water management, adopting conservation agriculture, improving pest management, better weather forecasts, crop insurance and harnessing the indigenous technical knowledge of farmers. The Institute is working on the following strategies for climate change adaptation.
5.1. Development of cropvarieties tolerant to climatic stresses: • Development of new crop varieties with higher yield potential and resistant to multiple stresses (heat, drought, flood, salinity) will be the key to maintain yield stability. The Institute screened large number of germplasm and identified Nerica L44 and N22 as novel sources of heat tolerance in rice, which are being used in breeding program. In an effort to map the QTLs governing heat tolerance recombinant inbred line mapping populations are being generated involving heat tolerant genotypes namely L44 and N22, which are in F4 generation.
• Marker assisted backcross breeding was carried out using molecular marker linked to the QTL governing drought tolerance, qDTY1.1 into Pusa Basmati 1 and qDTY3.1 into Pusa 44 and 41 (in Pusa Basmati 1 background), 36 (in Pusa 44 background) desirable progenies have been identified in BC3F2 generation and BC3F3 families have been grown at off-season nursery, RBGRC-IARI, Aduthurai for further selection. These improved genotypes will help in mitigating intermittent drought as well as save irrigation water in rice grown under irrigated conditions.
• Standardized physiological trait-based phenotyping protocol for screening for heat and drought tolerance in wheat. Introgression of QTL's for physiological traits for imparting drought and heat tolerance in the background of popular wheat varieties are in progress.
• Identified thermo-stable enzymes of key biosynthetic pathways from wheat, which can maintain the metabolic processes of the plants even under high temperature. It also identified and validated heat-responsive microsatellite markers, which can be utilized for screening large germplasm of wheat for the development of climate smart crop.
• Maize genotypes tolerant to low and high temperature tolerance were identified. Total antioxidants, peroxidase and catalase activity showed high values in tolerant lines in comparison to susceptible lines. Maize inbred lines were also screened for multiple disease resistance. Maize genotypes in each of the tolerant and susceptible group are further being advanced for more detailed analysis.
• Two wild species i.e., L. peruvianum and L. pimpinellifoium crossable to cultivated tomato have been identified for temperature stress tolerance. Among cultivated genotypes (Pusa Sadabahar and TH-348) and hybrids (DTH-9 and DTH 10) were identified for heat stress tolerance.
5.2. Developing and promoting water-saving technologies: • To enhance water availability, the Institute is renovating water harvesting structures and deepening of open wells through community participation.
• The Institute is promoting water conservation, integrated water saving technologies such as such as underground pipeline network, drip, sprinkler and raingunirrigation, laser-aided land leveling andcrop need-based irrigation for higher water use efficiency.
• Water resource availability as impacted by climate change scenarios is estimated to develop adaptability options in Gomti river basin in the IGP.
• Drip irrigation system has been introduced in rice cultivation to reduce GHGs emission and saving water.
• A composite drought index has been developed to monitor drought conditions on a regional basis. It can be used for near real time drought monitoring system.
5.3. Conservation agriculture: • The Institute has shown that conservation agriculture is useful to enhance resource use efficiency, provide economic benefits and minimize unfavourable climatic stresses.
• Zero-tillage can allow farmers to sow wheat sooner after rice harvest, so that the crop escapes the terminal heat stress.
• Bed planting (narrow/broad) of crops with residues saves water, enhance farmers' income and also provide resistance to lodging of crops due to unseasonal rains and hailstorm, which are occurring very frequently in recent years.
• It was successfully shown that the highly intensive and water-demanding rice-wheat system of the north-west India can be diversified to zero-till wheat followed by summer mung bean and direct-seeded rice to save water, increase income and reduce GHGs emisison.
• A 5-year study showed that conservation agriculture-based cotton-wheat system with both seasons’ crop residues retentions under zero-till permanent broad bed provides more adaptation under changing climate through imparting higher productivity, profitability and resource (water, nutrients, energy)-use efficiency. It could be more climate-resilient than the conventional rice-wheat system.
• Zero tilled direct seeded rice (DSR) with summer mungbean (SMB) residue retention - rice residue (RR) retention in ZTW – ZT summer mungbean (SMB) system with wheat residue performs better than conventional transplanted rice and –conventionally tilled wheat (TPR-CTW) system through imparting higher productivity, profitability and resource-use efficiency. It reduced methane emissions significantly and led to 35% decrease in GWP compared to TPR-CTW.
5.4. Improved nutrient management: • The adverse impact of climate change on crop yield could be compensated with more and efficient use of plant nutrients. For example, yield reduction because of late sowing of rice as a result of delayed onset of monsoon can be compensated with higher and timely application of N.
• Site-specific nutrient management and demand-driven N use using a leaf colour chart promote timely and efficient use of N fertilizer, minimizes GHGs emission and provide adaptation benefits.
• Delay in the onset of south-west monsoon delays the transplanting of rice, which reduces yield substantially. The yield loss due to late-planting of rice can be compensated by demand-driven application of neem oil coated urea N using leaf colour chart.
• The Institute is developing a microbial consortium-based technology for increasing the intrinsic ability of crop plants in withstanding moisture stress for longer duration of time and supplementing nutrients.
5.5. Pest forecasting:• Small and marginal farmers having subsistence farming need assistance for making their agriculture profitable so they can improve their livelihoods and eventually help themselves escape from the ill-effects of climate change. Integration should be made among crop production, livestock, agro-forestry and fish production to improve the production, income and livelihood.
• This is especially important for small and marginal land holding situations as prevailing in large part of the country.
• The Institute has laid out an integrated farming system model in its farm for demonstration purposes.
5.6. Integrated farming system: • Changes in temperature and variability in rainfall would affect pests incidence and virulence of major crops as climate change will potentially affect the pest/weed-host relationship.
• To assess the impacts of elevated temperature on diseases a generic model has been developed to prioritize diseases for development of management advisories. Based on priorities monitoring and forecasting systems have been developed especially for spot blotch and yellow rust in wheat and neck blast and brown spot in rice.
• The InfoCrop model has been updated to simulate the effects of biotic stresses on crop yield and optimize control measures.
5.7. Weather forecasting and dissemination: • Weather forecasting and early warning systems will be very useful in minimizing risks of climatic adversaries. Information and communication technologies could greatly help researchers and administrators develop contingency plans.
• The Institute prepares agro-met advisories and disseminate it through E-mail to ATIC, KVKs, State Agri. Dept., IFFCO, NGOs, ATMA, e-choupal and IARI and IMD websites. It also prepares weather bulletins and communicates to farmers through telephone, E-mail and SMS.
• It has developed and promoting the knowledge-based Extension Service with Pusa mKRISHI®.
5.8. Decision support system: • The InfoCrop decision support system has been developed and updated for predicting yields of major crops in climate change scenarios, yield gap analysis, crop management optimization, yield forecast and forewarning for disease and insect infestation in major crops. InfoCrop V2.1 is released and is used in 32 countries.It can be downloaded from www.iari.res.in.
• Simulation models were developed for disease (leaf blast, yellow rust and spot blotch) development and distribution for real-time monitoring and climate change adaptation.
• Simulation with coupled BPH-InfoCrop model revealed that BPH population will not be affected by temperature rise under Delhi conditions by 2020 but further temperature rise will have an adverse effect on it by 2050.
• A multivariate aggregated drought index has been developed, which comprehensively considers all categories of drought (meteorological, hydrological and agricultural).
• A real time crop environment and crop condition monitoring system was developed at district level for India using remote sensing data received at IARI satellite ground station. The system generated real time maps are made available on public website for use by stakeholders.
6. Technology demonstration and capacity building:• With promotion of climate resilient technologies and behavioral and institutional interventions, initiatives have been made for development of climate smart village in district Gurgaon. The outcomes are also being tested at 3 locations (Uttar Pradesh, Bihar and West Bengal) in the IGP.
• The Institute addressed the climate change related agricultural and livelihood challenges of drought (district Dhar in Madhya Pradesh and district Mewat in Haryana) and flood (district Ganjam in Odisha and district Raigad in Maharashtra) through augmenting participatory approach and community action, strengthening village institutions and institutional convergence, and promotion of community-based seed bank, water conservation measures, micro-irrigation systems, crop diversification and protected cultivation.
• Interventions under irrigated Rice-wheat system majorly focused upon climatic risks of drought and heat stress. Factors for vulnerability were related to more to human capital (lack of knowledge and skill in climate resilient technology) and social capital (community action and networks) rather than financial capital. Therefore, stress was laid upon developing community capacities for enhanced utilization of climate resilient technologies particularly water saving technologies through trainings and demonstrations.
• The major interventions included community based dissemination of climate resilient technologies like direct seeded rice and zero-till and raised bed system of wheat cultivation; use of crop residues as mulching, raised bed system with plastic mulching, drip irrigation and pheromone traps in vegetables; Integrated weed and nutrient management, insect pest Management, use of leaf colour chart in paddy and wheat, use of bio fertilizers, knowledge-based Extension Service with Pusa mKRISHI®, monitoring real-time crop growth using satellite, soil health card and soil test based fertilizer management.
• Village Climate Risk Management Committees (VCRMC), Pusa Chetna Krishak Clubs, Farmers’ Field Schools, Custom Hiring Centres and Self-help Groups engaging Women have been established for capacity building and promotion of climate resilient technologies.
7. Facilities for climate research at IARI: The state-of-art national research facilities such as satellite data receiving and management system, plant phenomics (laboratory and field), ecological simulation modeling laboratory, eddy Co-variance flux tower, free air carbon dioxide enrichment facility, open top chambers, temperature gradient tunnel and gas chromatography for GHGs analysis have been commissioned. The controlled environmental chambers, free air carbon dioxide and temperature enrichment facility are in the process of commissioning.
8. Conclusion: Climate change and climatic variability are likely to affect sustainability of agricultural production thereby affecting national food security. Adoption of climate resilient technologies can help in coping up with the challenge of climate change. Some climate resilient technologies like growing heat/drought-tolerant crop varieties, changes in crop management practices, adoption of water management technologies, increasing nutrient-use efficiency, development of improved farm machineries, adoption of resource conserving technologies and better pest management, access to weather forecasts, introduction of crop insurance products and harnessing of indigenous knowledge can help in agricultural adaptation to the changing climate. There is a need of wide dissemination of information on such technologies to protect agricultural production. Exchanging information and providing technical advice on improving efficiency, productivity and resilience of agriculture at regional and national scales should be considered. Besides, capacity building and awareness on multiple advantages of climate-smart, sustainable agricultural technologies should be promoted. Farmers should be ensured with better support price of agricultural produce to enable them to cope with higher adaptation cost of cultivation under changing climatic scenarios.