Climate change and variability will impact water availability and the food security of India. Trend analyses of historical data indicate an increase in temperature and changes in rainfall pattern in different parts of the country. The general circulation models (GCMs) also project increased warming and changes in precipitation patterns over India. This chapter presents examples of model applications in water management and crop yield simulation in India, focusing on climate change impact assessment. Simulation models have been successfully applied for rotational water allocation, deficit irrigation scheduling, etc. in different canal commands. Application of a universal soil loss equation in a distributed parametric modeling approach by partitioning watershed into erosion response units suggests that by treating only 14% of the watershed area, a 47% reduction in soil loss can be achieved. Simulation studies conducted using different hydrological models with different climate change projections and downscaling approaches showed varied hydrological responses of different river basins to the future climate change scenarios, depending on the hydrological model, climate change scenarios, and downscaling approaches used. Crop yield modeling showed decreases in irrigated and rainfed rice (Oryza sativa L.) yields under the future climate change scenarios, but the decrease is marginal for rainfed rice. Maize (Zea mays L.) yields in monsoon may be adversely affected by a rise in atmospheric temperature, but increased rain can partly offset those losses. Wheat (Triticum aestivum L.) yields are likely to be reduced by 6 to 23% and 15 to 25% during the 2050s and 2080s, respectively. A combined bottom-up participatory process and top-down integrated modeling tool could provide valuable information for locally relevant climate change adaptation planning.

Colin J. Chartres, 'Water and food security: stumbling toward Malthusian oblivion or pioneering cornucopia?', 2014 | The International Water Management Institute (IWMI) was established in Sri Lanka by the Ford Foundation and others in the mid-1980s. Today, IWMI works in about 20 countries. Colin Chartres reflected on the history of IWMI's work and described important studies that have advanced the understanding of water and food

Asia accounts for 70% of the world's irrigated area and is home to some of the oldest and largest irrigation schemes. While these irrigation schemes played an important role in ensuring food security for billions of people in the past, their current state of affairs leaves much to be desired. This paper takes forward the IWMI-FAO-ADB (Asian Development Bank) recommendation of a five pronged approach for revitalizing Asia's irrigation and provides a region specific road map for doing this. The underlying principle of these multiple strategies is the belief that the public institutions at the heart of irrigation management in Asia need to give up comfortable rigidity and engage with individual users' needs and the demands placed by larger societal chang | Aditi Mukherji et al., 'Growing more food with less water: how can revitalizing Asia's irrigation help?', 2014

Freshwater food webs are dominated by aquatic invertebrates whose trophic relationships are often poorly known. Here, I used laboratory experiments to study the role of a water bug, Sigara striata, as a potential predator and prey in food webs of stagnant waters. Multiple-choice predation experiment revealed that Sigara, which had been considered mostly herbivorous, also consumed larvae of Chironomus midges. Because they often occur in high densities and are among the most ubiquitous aquatic insects, Sigara water bugs may be important predators in fresh waters. A second experiment tested the role of Sigara as a potential prey for 13 common invertebrate predators. Mortality of Sigara inflicted by different predators varied widely, especially depending on body mass, foraging mode (ambush/searching) and feeding mode (chewing/suctorial) of the predators. Sigara was highly vulnerable to ambush predators, while searching predators caused on average 8.1 times lower mortality of Sigara. Additionally, suctorial predators consumed on average 6.6 times more Sigara individuals than chewing predators, which supports previous results hinting on potentially different predation pressures of these two types of predators on prey populations. The importance of these two foraging-related traits demonstrates the need to move from body mass based to multiple trait based descriptions of food web structure. Overall, the results suggests that detailed experimental studies of common but insufficiently known species can significantly enhance our understanding of food web structure.

In the tropics, the water potential of a region cannot be adequately assessed from precipitation alone due to the seasonal character of rainfall and even more so owing to the changing climate scenario. It is therefore necessary that in any agro-climatological program, there must be a clear understanding of the actual amount of water that evaporates and transpires (AET), and the amount of water that would evaporate and transpire if water were always readily available (PET). This could be done through the method of the water balance. The present work examines the water budget of parts of the Imo river basin and its implications for improved crop production through supplementary irrigation schedules. It was observed, that the study area is already facing moisture-stress. This is because even during rainy months supplementary irrigation is required to compensate for the occasionally moisture deficit due to increased evapotranspiration. The study showed that cultivation of maize, rice and tomatoes can be carried out on an all-year round basis under a scientific irrigation scheme. Thus the study provided farmers with guideline on the period and quantity of water required for supplementary irrigation, a development which will prevents wilting of plants before the application of needed water.

The symposium (2014) focused on the challenges of crop production faced by farmers in the Sahel region. The presentation covers a three-year fertilizer micro dosing (MD) project that was combined with rainwater harvesting (RWH). The techniques are assessed in terms of effects on crop production and family income. It also explores the “warrantage” or inventory credit system where harvested crops are stored and used as collateral to access loans and credit. With improving crop varieties, MD and RWH can increase yields up to 200%. There is no evidence that the process caused land degradation or yield decline, suggesting long term sustainability.

In the tropics, the water potential of a region cannot be adequately assessed from precipitation alone due to the seasonal character of rainfall and even more so owing to the changing climate scenario. It is therefore necessary that in any agro-climatological program, there must be a clear understanding of the actual amount of water that evaporates and transpires (AET), and the amount of water that would evaporate and transpire if water were always readily available (PET). This could be done through the method of the water balance. The present work examines the water budget of parts of the Imo river basin and its implications for improved crop production through supplementary irrigation schedules. It was observed, that the study area is already facing moisture-stress. This is because even during rainy months supplementary irrigation is required to compensate for the occasionally moisture deficit due to increased evapotranspiration. The study showed that cultivation of maize, rice and tomatoes can be carried out on an all-year round basis under a scientific irrigation scheme. Thus the study provided farmers with guideline on the period and quantity of water required for supplementary irrigation, a development which will prevents wilting of plants before the application of needed water.

Peter G. McCornick, Seleshi Bekele Awulachew, M. Abebe, 'Water-food-energy-environment synergies and tradeoffs: major issues and case studies', 2014

Recognizing the importance of policy debate and knowledge sharing in the field of development, the Arab Fund for Economic and Social Development and the World Bank (Middle East and North Africa Region) agreed in March 2010 to hold joint high-level development seminars around issues pertaining to the Arab World. These were to be known as the Arab Development Symposia (ADS) and will be held on a regular basis, every 18 months or so, at the Arab Fund premises in Kuwait. The goal was to provide an opportunity for policymakers, practitioners and academicians to share ideas and experiences on topics which are high on the Arab development agenda. As such, the ADS series complement other fora for research and knowledge sharing and dissemination such as the Economic Research Forum (ERF) and the Research Initiative for Arab Development (RIAD).