CLIMATE CHANGE IMPACTS ON IRRIGATION SYSTEM AND ITS ADAPTATION NEED

CLIMATE CHANGE IMPACTS ON IRRIGATION SYSTEM AND ITS ADAPTATION NEED

S. B. THAKUR[1]

Abstract

Irrigation is an essential to increase agriculture production and productivity for sustainability of country's economy. Agriculture contributes one-third of national GDP and two-third of labor employment for livelihoods. Water greatly influences photosynthesis, respiration, absorption, translocation, utilization of mineral nutrients, and cell division in plant system. Rapid change in climate system has raised the concern of floods and droughts and their impacts on existing arrangements for irrigation design and management system.  Glacial and snow melt is an important source of the lean flows of snow-fed rivers but it is predicted that possible decline in river and stream flows in future.  All small farmers are vulnerable to the climate change impacts resulting adverse effects in agricultural productivity and food security. The current policies, plans, strategies emphasized on the climate change impacts and its adaptation in irrigation system. The absence of proper mechanisms for water augmentation, conservation, distribution, and efficient use are the major basis for climate change adaptation. This paper is intended to highlight the impacts of climate change and the climate change adaptation on irrigation system to build adaptive capacity and promote climate resilient irrigation system in Nepal.

Key words: Adaptation, agriculture, irrigation, climate change, and resilient.

INTRODUCTION

Nepal's agriculture is mostly depends on the monsoon rain-fed and it is highly sensitive to climate change. Agriculture is the major economic sector, it contributes nearly one-third of the national gross domestic product (GDP) and two-thirds of labor employment to economically active population (CBS, 2012). Twenty one percent of total land of 28% of arable land is cultivated and 54 % has irrigation facilities. The land holding size is only 0.68 ha per household and over 50% of farmers have less than 0.5 ha cultivating land.

Water supports agriculture and other livelihood functions. Water greatly influences photosynthesis, respiration, absorption, translocation and utilization of mineral nutrients, and cell division besides some other processes (india.agronet.com, 2017). As much as 85% of global water is used for irrigating the agriculture land, of which 15 to 35% is predicted unsustainable (IFPRI, 2016). Irrigated land can have up to five times high yields than that of the rain-fed areas (Devrajan, 2011). Irrigated agriculture produced 40% food and agriculture commodities from 17% agriculture land. This informs food security critically dependent on irrigation (Wallingford, 1997).

Smallholder farmers are disproportionately vulnerable to the impacts of climate change as a result of poverty, marginalization and reliance on natural resources. Climate change is likely to lead to decreasing crop yields in most tropical and sub-tropical regions, negatively impacting agricultural sectors and reducing food security in developing countries. It is imperative to identify approaches that strengthen ongoing economic development efforts and enhance the adaptive capacity of farmers, their households and their communities (Frank and Buckley 2012).

In 2005/06, eastern Tarai faced rain deficit due to early monsoon, resulting to nearly 10% of the agriculture land left fallow and crop production was reduced by 12.5% on the national basis. The mid-western Tarai experienced heavy rain with floods which reduced production by 30% in the same year (Regmi, 2007). Both floods and droughts have declined food production significantly.

Nepal is experiencing temperature rise and change in precipitation pattern. The 2015 study of climate and climatic variation over Nepal showed 0.037 ⁰C/year and 0.012⁰C/year of an average trend of mean annual maximum and minimum temperature respectively during 1971-2012 period (NHMRCC, 2015). There is no clear indication on precipitation change but average precipitation has increased by 0.7 mm/year based on spatial interpolated data. The 24-hour accumulated extreme precipitation is higher over Churiya, exceeding 400mm/day (Table 1). The study reported 13 June as mean summer monsoon onset date and 25 September as the withdrawal date based on average of 1968-2014 data. Duration of monsoon is increasing at the rate of 5 days/decade.

Table 1: Climate trend in ecological regions

Region	Maximum Temperature Trend (0C/year)	Minimum Temperature Trend (0C/year)	Precipitation trend (mm/year)
Tarai	0.015	0.017	-1.3
Siwalik	0.024	0.013	0.6
Middle Mountain	0.043	0.013	-2.3
High Mountain	0.053	0.008	0.2
High Himalaya	0.052	0.009	6.6
Country	0.037	0.012	0.7

Source: NHMRCC, 2015.

Climate variability confirms 'too much water' (accelerating flood) and 'too little water' (drought) resulting to severe water scarcity and this is aggravated due to climate change impacts on agricultural productivity through irregular and inadequate irrigation facilities. This will result in adverse impacts in food security.

Agriculture sector is not performing well due to shortage of water for irrigation. Farmers are the biggest global water users and farmers operate, directly or indirectly, at the world market for agricultural products (Alvaro et. al., 2010). It is most likely that climate change will make the situation worse.  Adaptation to changing water resources is necessary at the local scale.

With this concern, the paper is intended to highlight the impacts of climate change and the climate change adaptation on irrigation system to build adaptive capacity and promote climate resilient irrigation system in Nepal for communicating the stakeholders.

METHODOLOGY

This paper is based on the review of published reports, journal articles and research papers, both national and international. The government policies, plans, and strategies were also reviewed to understand national focus and priorities in exploring opportunities to make irrigation system climate change-resilient.

DISCUSSIONS

Water is indispensable for life, of the total earth water 97.5% is saltwater and only 2.5% is freshwater of the all water on Earth. About 70% of the freshwater is frozen in the icecaps of Antarctica and Greenland. Human being uses only 0.7% water from total worldwide water resources directly (WEC, 2011).

1. Understanding the source of irrigation

Glacier melt, precipitation and groundwater are major sources of water. The perennial rivers such as Koshi, Gandaki, Karnali and Mahakali originate in the Himalayas and carry snow-fed flows with significant discharge, even in the dry season. The perennial rivers like Mechi, Kankai, Kamala, Bagmati, West Rapti and Babai rivers originate in the Midlands or Mahabhabharat range and are fed by precipitations as well as groundwater recharge, including springs with seasonal fluctuation in discharge. Seasonal and small rivers in the Tarai originate from the southern Siwalik range with little flow during the dry season and it is characterized by flash floods during the monsoon. In a nutshell, water origins are expected highly vulnerable to climate variability and change.

The major source of river water is the glaciers, has reduced from 5312 Km² in 2010 to 4212 Km² in 2014 (MoSTE, 2014).  Nepal has 225 Billion Cubic Metres (BCM) of water available annually and only 15 BCM has so far been utilized for economic and social purposes (MoSTE, 2014). Insufficient rain and temperature rise cause drought, whereas intense rain in short period reduces groundwater recharge by accelerating runoff and causes floods. Both situations induce negative impacts in the agriculture (ICIMOD/UNEP, 2007).

In Nepal, climate change will likely increase in average annual water yields from Himalayan Rivers at least for the next 15- 20 years. It is anticipated that water yields of the rivers would fall dramatically since glaciers would have mostly melted-out by 2035 (Paudel and Gautam, 2011).  The Intergovernmental Panel on Climate Change (IPCC) forecasted that the Himalaya will be converted into a black rocky mountain without snow and ice by the year 2035 (Paudel and Gautam, 2011). Although the forecast may not be true to that extent, Nepal will likely face severe water scarcity along with other South Asian nations. Glacial and snow melting is an important source of the lean flows of four large rivers (Kosi, Narayani, Karnali and Mahakali). Medium-sized rivers also depend on impacts of climate change on the Himalayan snow/ice conditions. It is evident that rivers, the main sources of irrigation, are highly vulnerable to climate change. It is likely that irrigation system will also be affected by climate change. As Nepal's greenhouse gas (GHG) emission is insignificant (only 0.027% of the global total) and her effort in reducing GHGs emission will not be much significant at the global level, it is natural that Nepal should focus on climate change adaptation.

2. Relation of agriculture and irrigation in Nepal

Nepal's total arable land is only 4,121,000 ha (28 %) of total 14,718,100 ha area and cultivated land is 3,091,000 ha (21%) which indicate that there is still 7% land can be made under cultivation for the increasing population. However, for taking potential production of agricultural and horticultural crop, 1,227,353 ha (54%) area is under irrigated land. This shows that there is lot of scope for the irrigation facility (Table 2).

Table 2: Area under arable, cultivated, irrigable and irrigated and its percentage

Detail	Total arable land	Total cultivated land	Irrigable land	Total irrigated land
Area (ha)	4121000	3091000	1766000	1227353.02
%	28(As % of total area)	21(As % of total area)	67 (As % of total cultivated)	54 (As % of total cultivated)

Area under the types of irrigation to the irrigated land, the major types of irrigation are surface, ground water and non-conventional. The highest area under the surface irrigation is 936,184 (76.28%), followed by ground water 278,158 ha (22.66%) and lowest area under the non-conventional type is 13011 ha (1.06%). The flooding and conventional irrigation has more area which is need to develop more water efficient.

Table 3: Area under various types of irrigation sources and its percentage 

Description	Total irrigated	Surface			Ground water			Non-conventional
		FMIS	Surface	Total surface	Shallow tube well	Deep tube well	Total
Area (ha)	1227353.02	621663	314521	936184	240058	38100	278158	13011.02
%	54	66.40	33.60	76.28	86.30	13.70	22.66	1.06

3. Understanding the impacts of the climate change on irrigation

The major crops grown under irrigated conditions are found to contribute to a higher level of crop productivity and net income than those in rain-fed conditions. The water sector is foremost vulnerable to climate change than other sectors. Nepal's irrigation sources are predominantly from rivers and ground water. These are mostly originated from glacial and snow melting, and precipitation which are highly susceptible to climate change.

The principal threats to the irrigation sector in Nepal are temperature rise leading to an increase in evapo-transpiration rate, altering effective rainfall, increasing river flows leading to higher (80%) reliable river discharges, and also increasing intensity of rainfall, and decreasing return periods leading to an increase in flash floods, storms and landslides. These threats will lead to shifting irrigation demand and supply that will require a change in irrigation planning, and changes in flooding which will require modifications to irrigation infrastructure design.

Though, Irrigation had a positive impact on crop diversification and commercialization. Farmers having irrigation and market facilities were found to shift from traditional cereal production to commercial vegetable production due to the scarcity of the water (Regmi et.al. 2000). Even with sufficient irrigation water in mountain "khet" (irrigated) areas but low temperature of irrigation water has a negative effect on crop productivity.

In the mid-hills, changes in rainfall and temperature and decrease in soil moisture availability will result in early maturation of crops, crop failures and reduce agricultural productivity. In addition, it will likely decrease run-off water to feed natural streams (used for irrigation) and re-charge natural ponds, reservoirs and lakes. In the Tarai region similar issues. were noted, particularly reduced recharge rate of groundwater that has resulted in a reduction of discharge of water in shallow and even deep tube-wells, failure of canals, drying of rivers, rivulets, streams, lake, ponds, reservoirs and wells for irrigation for crops (MoE, 2010).

Services from irrigation system is becoming poor due to alternation of precipitation pattern, changes in groundwater availability, change in surface flows (extreme rainfall patterns, flood, droughts, etc.). Most of the irrigation systems in Nepal are fed by medium or small rivers, which entirely depend on the rain. Moreover, water use efficiency and agricultural productivity in both the traditional farmer managed practices and large public irrigation system are found to be low. Among the other obstacles, inadequate irrigation is the major limiting input to increase agricultural productivity.

Though rainfall provides partial protection against drought, irrigated agriculture is very dependent on the rainfall. Any changes to rainfall patterns and other climatic parameters will affect both supply and demand for irrigation water and will have a direct impact on its system.

The reduced run-off rivers, due to changing rainfall patterns in the catchment; increased flood flows due to more intense rainfall, increased demand for water due to higher temperatures and more erratic rainfall, and changes in crop suitability due to temperature changes are the major and important adverse effects for irrigated agriculture. Furthermore, FMIS is facing challenges by population growth, pressure for increased demand on food, environmental degradation, and completion on the allocation of water (Pradhan, 2000). Negative impacts of climate change on water resources resulting to adverse effect affects on irrigation sector, agriculture productivity, food availability and poverty.

4. Realizing the adaptation needs in plans, policies and strategies

The fourteenth plan realized that risk management of climate change-induced effects on water availability is the major challenge of irrigation sector (NPC, 2016). It also stressed on ensuring user's participation for sustainable management as well as development and extension of irrigation system and achieving goals of Agriculture Development Strategy (ADS) and promoting climate change adaptation. Efficient use of irrigation system and participatory management is equally emphasized.

The Sustainable Development Goals (SDG) stresses in second goal to "end hunger, achieve food security and improved nutrition and promote sustainable agriculture", and the sixth goal focuses to "ensure availability and sustainable management of water and sanitation for all". To achieve them, it is necessary to make irrigation facilities climate-friendly and resilient.

The Agriculture Development Strategy, 2014 has targeted to provide year round irrigation facility from 18% in year 2010 to 60% and 80% by 10 years and 15 years respectively (MoAD, 2014). The Strategy has realized the impact of climate change and emphasizes to introduce climate change adaptation in order to increase farmers' resilience to climate change.

The Irrigation Policy, 2014 describes climate-related risks associated with the irrigation infrastructure. The policy realized the climate change impacts on irrigation sector. The Policy underscores the importance of availing sustainable and reliable year round irrigation facilities to all agricultural lands so as to contribute to agriculture productivity by extension of irrigation services for reducing poverty. The Policy opens avenues to develop climate change-friendly irrigation facilities to achieve its objectives, avail round-year irrigation facility through effective management of existing water resources, develop institutional capacity of water users for sustainable management of existing systems, and enhance knowledge, skills and institutional working capability of technical human resources, and water users and NGOs relating to development of irrigation sector. The Policy aims to study the impact of climate change and water-induced disasters to implement adaptation programmes.

The National Adaptation Programme of Action (NAPA), 2010 includes priority activities-related to irrigation like integrated watershed management in Churia, on-farm soil and water conservation initiatives, water management in river basin areas, flood management, promotion and up-scaling of Multi Use System (MUS), and up-scaling and implementation of non-conventional irrigation systems.

The Climate Change Policy (2011) aims to improve livelihoods by mitigating and adapting to the adverse impacts of climate change, and adopting low carbon emissions socio-economic development path. The Policy provides multiple opportunities to promote climate change adaptation and make the development infrastructures climate-friendly and resilient.

Most of the current plan, strategy, policy and programme emphasize on the impacts of climate change on the sector, its threats and importance of climate change adaptations measures.

 

5. Addressing the climate change impacts on irrigation

Climate change is inevitable and is expected that the accelerating rate of climate change impacts on water sector have made need of climate reducing climate vulnerability and adopting to climate change adaptation measures. So, only adaptation measures and strategies can modify the negative impacts of climate change. To adapt change in climate and weather extremes, wider choices may become increasingly necessary. Climate change impacts on water resources may be addressed by focusing on research, optimum observation network, strong data-base, and research based action oriented program/projects. This will lead to intensive resource and budget investment for climate change adaptation in irrigation sector. Some of the irrigation practices such as MUS, hydraulic ram pump, treadle pump, drip irrigation, and micro-sprinkler are catalogued as climate change adaptation approaches and technologies are realized in policy documents.

The promotion of conjunctive use of ground and surface water-based irrigation systems along with new/non-conventional irrigation systems such as rain water harvest, pond irrigation, sprinkler irrigation, drip irrigation and treadle pump irrigation. To make the system effective for round the irrigation, it is necessary to develop storage facilities for winter season. The development and implementation of reservoir-based and inter-basin water transfer facilities and integrated water resources management. Some of the adaptation measures are depicted in Table 4.

Table 4: Climate change adaptation strategies in irrigation system

Drought	Sedimentation caused by flood	Water scarcity
·  Impoundment for the groundwater recharge ·  River linking of adjoining rivers for regular run-off flow ·  Development of river basin transfer ·  Development of integrated services to water ·  Planting of trees for shade to water resources ·  Snow/dew harvesting in mountainous region ·  Improve irrigation systems and their efficiency ·  Improve use/store of rain and snow water. ·  Use marginal and waste water resources. ·   Change irrigation practices. ·  Reduce tillage to lessen water loss ·  Incorporation of manures and compost, ·  Practice of cover cropping increase soil organic matter to improve water retention. ·  Alter agronomic practices ·  Pre-warning system.	·  River linking of adjoining rivers for regular run-off flow ·  Tree planting for erosion control and soil conservation ·  Improvement of land management (Sustainable land management practices-SALT, bio-engineering, Agro-forestry, etc.) ·  Extension of sustainable agriculture soil and water conservation ·  Improve flood management ·  Improvement of design of canal and other irrigation system ·  Maintain hydro-met data system ·  Pre-warning system.	·  Develop  and  implement  watershed  management  plans  for  critical watershed areas ·  Increase the efficiency of use and reduce losses of irrigation water ·   Assessment of current water management practices for climate resilience and identify for improvement ·  Identify and map areas vulnerable to droughts and flood hazards and prepare disaster risk management plans ·  Design   rational   intra-basin   and   trans-basin   strategies   to   harness periodic surpluses of water in storage facilities ·  Lining irrigation canals would help reduce water loss ·  Tech­nologies as modern drip or sprinkler irrigation sys­tems would improve the application of water to crops ·  Effective water management through pricing, taxes, subsidies, and quotas to reduce water waste ·   Providing farmers incentives to adopt resource-efficient technologies and penalizing for unsustainable practices.

In addition,  Hu, (2011) reported that adapting to scenarios of reduced water availability may involve increased investments in water infrastructure to provide enough irrigation to maintain existing agricultural production, or a shift from current production to less water-consuming crops.

In India, Alam et al. (2007) also revealed that a combination of traditional and innovative technological approaches is used to manage drought risk. Technological management of drought may be development and use of drought tolerant cultivars, shifting cropping seasons in agriculture, flood and drought control techniques in water management; is combined with model-based seasonal and annual to decadal forecasts with early warning system to take appropriate drought protection measures.

Integrating activities in the national strategy for CCA and DRR, including drought risk loss insurance; improved water use efficiency; adopting and adapting existing water harvesting techniques; integrating use of surface and groundwater; upgrading irrigation practices at both the farm level and on the delivery side; developing crops tolerant to salinity and heat stress; changing cropping patterns; altering the timing or location of cropping activities; diversifying production systems into higher value and more efficient water use options; and capacity building of relevant stakeholders in vulnerable national and local areas (Abou Hadid, 2009; El-Quosy, 2009).

6. Understanding climate change resilient

Resilience building through knowledge, advocacy, research, and training by making information on drought risk accessible (UNISDR, 2007a). Building climate resilience at the community level through reducing risk and facilitating adaptation like improving access to water through region-specific activities such as rainwater harvesting and creation of water pools from precipitation and flood waters, for use for animals, pastureland, and crop irrigation purposes; improving the quality of livestock by introducing local selective breeds with higher productivity and more resilient to climate impacts; strengthened veterinarian services to reduce animal diseases and parasites and cross-border epidemic infections; and using traditional herding knowledge and techniques for adjusting animal types and herd structure to make appropriate for the carrying capacity of the pastureland and pastoral migration patterns. The formation of herders’ community groups and establishment of pasture co-management teams (Ykhanbai et al., 2004), along with better community-based disaster risk management, could also facilitate effective DRR and CCA.

Conclusion

As agriculture is the most important sector of Nepal's national economy and agriculture largely depend on irrigation.  Temperature rise and change in precipitation pattern causing drought and flood have negative effects on irrigation systems such as infrastructure, water flow, supply and demand of water, sedimentation, crop suitability, etc. It resulted in reducing agriculture productivity and food production and accelerating poverty. It is imperative to identify approaches that strengthen ongoing economic development efforts, reducing climate change vulnerability and enhance the adaptive capacity of farmers, climate vulnerable communities and ecosystems. The appropriate adaptation measures are essential for making irrigation facilities climate-resilient through research, policy arrangements, institutional capacity building and substantial investment in irrigation sector. The long term adaptation planning will support the irrigation systems, and agriculture practices to enhance the adaptive capacity and to build resilient to climate change.

Acknowledgement

We would like to express our sincere appreciation to the Ministry of Population and Environment (MOPE), and UK Aid, ACT, OPM and Practical Action for giving us the opportunity to use information as contained in the stocktaking report of the NAP formulation process and approach paper. We thank Mr Batu Krishna Uprety, Team Leader NAP process for his kind support and cooperation. I also thank to MoAD for coordinating agriculture and food security (nutrition) thematic sector.

References

           

Abou-Hadid, A.F., 2009. Arab Environment. Climate Change. Impact of Climate change on Arab countries. Report   of Arab Forum for Environment and Development. 2009. Eds Mostafa K.Tolba and Najib W. Saab.

Alam, Mozaharul and MD Golam Rabbani (2007), "Vulnerabilities and responses to climate change for Dhaka", Environment & Urbanization Vol 19, No 1, April, pages 81-97

Alvaro C., R. Katrin, B. Richard, P. Falloon, A. Wiltshire and S.J. Richard, 2010. Climate change impacts on global agriculture, Kiel Institute for the World Economy, Hindenburgufer. 66, 24105 Kiel, Germany

CBS. 2012. Nepal Living Standard Survey 2011/12, Government of Nepal Central Bureau of Statistics.

Devrajan, S., 2011. Information on the costs and benefits of irrigation in the Zambezi River Basin. Africa Climate Change. Irrigation and Climate change.

DOI & MoSTE. 2014. Irrigation Sector Adaptation Plan Framework for Guidelines: Synthesis Report on Adaptation to Climate Change. Prepared by ICEM - International Centre Environmental Management with the Nepal Ministry of Science, Technology and Environment (MoSTE) and Department of Irrigation (DOI) as part of TA – 7984 NEP: Mainstreaming Climate Change Risk Management in Development Project supported by ADB with funding from the Climate Investment Fund (CIF). Kathmandu, Nepal.

El-Quosy, D. 2009. Impact of Climate Change: Vulnerability and Adaptation. Fresh Water pp 75-86 Report of the Arab forum for Environment and Development. Mostafa K.Tolba and Najib W.Saab Eds

Frank, J and Penrose Buckley, C. 2012. Small-scale farmers and climate change. How can farmer organisations and Fairtrade build the adaptive capacity of smallholders? IIED, London

ICIMOD, UNEP, 2007. Global Climate Change and Retreat of Himalayan Glaciers in China, India, Bhutan and Nepal, pp7-19.

IFPRI, 2016. Global food policy report 2016. International Food Policy Research Institute, Rome

Indiaagronet.com available at https://www.indiaagronet.com/ indiaagronet/ water_management/ water_3.htm [Retrieved on 5 February, 2017]

MoAD, 2014. Agriculture Development Strategy (ADS) 2014. Ministry of Agricultural Development, Government of Nepal, Singhadurbar, KathmanduGovernment of Nepal

MoE , 2010, NAPA report 2010, National Adaptation Programme of Action., Ministry of Environment, Kathmandu

MoIr, 2014. Irrigation Policy, 2014. Ministry of Irrigation, Government of Nepal, Singhadurbar, Kathmandu.

MoSTE, 2014. Nepal: Second National Communication. Ministry of Science, Technology and Environment, Singh Durbar, Kathmandu

NHMRCC, 2015. Study of Climate and Climatic Variation over Nepal. A study commissioned by the Department of Hydrology and Meteorology and prepared by Nepal Hydrological and Meteorological Research Centre and Consultancy (P) Ltd., Kathmandu.

Paudel S. and U. Gautam, 2011. Farmer managed Irrigation Systems Promotion Trust book, Nepal: Farmer Managed Irrigation System in the twenty first century: Coping with the climate change Available at http://chimalaya.org/2011/04/27

Pradhan P, 2000. Farmer Managed Irrigation Systems in Nepal at the Crossroad. Paper on 8th Biennial Conference of the International Association for the Study of Common Property (IASCP).

Regmi, B. R. and Adhikari, A., 2007. Human Development Report 2007/2008 - Fighting Climate Change: Human Solidarity in a Divided World - Country Case Study–Nepal, Human Development Report Office, Occasional Paper No 57

Regmi, P. P.; K. E. Weber and R. Loof, 2000. Water Resources Journal . The importance of irrigation in ecological restructuring: empirical evidence from Nepal. No.204 pp.29-38 ref.12

UNISDR, 2007a; UNISDR (United Nations International Strategy for Disaster Reduction); Words Into Action: A Guide for Implementing the Hyogo Framework. United Nations, Geneva, Switzerland (2007) Available at: http://www.preventionweb.net/english/professional/publications

Wallingford, H.R. 1997. "Priorities for Irrigated Agriculture" Occasional Paper No. 1, Department of International Development, UK.

Ykhanbai, H., E. Bulgan, U. Beket, R. Vernooy, and J. Graham. 2004. Reversing grassland degradation and improving herders' livelihoods in the Altai Mountains of Mongolia. Mountain Research and Development 24:96-100.

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[1]  Thematic lead of the working group on agriculture and food security to the NAP process, e-mail: shreebhagavanthakur@gmail.com