Water and Agriculture II
Compiled by Dr. Nüvit SOYLU
Sept 9 2014
Supply of bulk water for irrigation is under pressure from the demands of other water-using sectors, constraints on further water resource development and is compounded by poor maintenance of existing irrigation infrastructure.
Pressures on the supply of water for irrigation
Demand for water for non-agricultural uses is increasing in response to economic growth, rising populations and increased urbanization. Rising urban demands for water (for household and industrial use) pose a particular threat to agriculture because urban demands take priority over rural demands in situations of potential conflict. This is because existing urban supplies are usually polluted, they can be associated with high health risks (such as the risks of epidemic diseases), new urban supplies have to come from increasingly distant sources (owing to scarcity in supplies), and the economic benefits of urban water supplies exceed those of rural supplies.
Worldwide, withdrawals of water for household and industrial use quadrupled between 1950 and 1995, while withdrawals for irrigation only doubled in the same period (FAO, 2003c). In terms of future demand in developing countries, non-agricultural demand for water is forecast to increase by 100 percent between 1995 and 2025 and agricultural demand to rise by only 12 percent (given prevailing trends). Rosegrant, Cai and Cline (2002) observe that this is the "first time in world history" that absolute growth in non-agricultural demand for water will exceed growth in agricultural demand. It will result in a fall in agriculture’s share of total water consumption in developing countries from 86 percent in 1995 to 76 percent in 2025.
Increases in non-agricultural demands for water are coinciding with constraints on further development of new water sources. In combination, these two factors are creating increased water scarcity and they will result inevitably in the transfer of water from agricultural use to higher value household and industrial uses.
Governments and donors have traditionally justified allocation of water to agriculture on grounds of food security and rural development. These are examined below, followed by a brief overview of relevant aspects of the international consensus that has emerged in water management policy.
Irrigation enables greater agricultural production than is achieved with rainfed agriculture. The additional food production obtained with irrigation is essential for food security on a global level, and on a national level for some countries. National food security is attained either through the pursuit of self-sufficiency in food (i.e. meeting demand through domestic production) or through a combination of domestic production and imports. Food self-sufficiency was once a widespread objective and some nations still aspire to it. It creates savings in foreign exchange, protects domestic producers and consumers from the fluctuations of world markets, ensures rural food supplies and contributes to a political sense of national security. However, it has disadvantages. In arid countries, a self-sufficiency policy can increase allocations of water to agriculture at the expense of industrial and household water use, and can contribute to the overextraction of groundwater resources.
Global demand for food is increasing as the population continues to grow and increase in prosperity. Demand pressure is concentrated in developing countries, where demand for agricultural products is forecast to increase at an average rate of 2 percent per year from 2000 to 2030 (FAO, 2002b).
Increased demand for food in developing countries will be offset at a national level, to various extents, by increased agricultural production. With the exceptions of sub-Saharan Africa and Latin America (where rainfed agriculture has greater significance), irrigated agriculture will provide much of this increase. In developing countries collectively, irrigated agriculture will provide 57 percent of the additional 256 million tonnes of cereals that will be produced in 2025 relative to 1995. Irrigation increases agricultural production through both the expansion of cultivable area beyond that possible under rainfed agriculture and higher crop yields. FAO (2002b) predicts that 70 percent of the increase in agricultural production that is forecast to occur in developing countries from 2000 to 2030 will come through increased yields, 20 percent through expansion of crop area and 10 percent through increased cropping intensity
Climate change is expected to affect agricultural production in developing countries, particularly through increases in temperature in arid regions (which will reduce the potential for crop production) and greater variability in the climate (which will cause increases in the frequency and duration of crop water stress). It will tend to increase local fluctuations in crop production and food supplies, particularly affecting food supplies and the incomes of poor people, and to increase national vulnerability to food insecurity . In certain regions, the effects could be significant even in the next few decades. For example, climate change could cause a 2-3-percent decline in cereal production in Africa by 2020 or 2030. Assuming that other factors remain constant, this would increase the number of people at risk of hunger by 10 million (FAO, 2003c).
Demand for food is not met solely by domestic production in many developing countries; imports of food are required to varying extents. In the Near East and North Africa, domestic cereal production represented 63 percent of demand. In sub-Saharan Africa and Latin America (including the Caribbean), it represented 82 and 88 percent of demand, respectively, and in East and South Asia, production met 95 and 102 percent of demand.
Reliance on imports is forecast to increase. They are predicted to grow to 14 percent of demand by 2030 (Bruinsma, 2003).
In an appropriate environment and with suitable planning investment in irrigation schemes can alleviate poverty both directly and indirectly through stimulation of the rural economy. Indeed, the purpose of many large scale schemes associated with the Green Revolution in Asia was more to do with addressing food security and poverty targets rather than direct commercial returns. (Plusquellec, 2002).
Increased food production from irrigated agriculture can confer nutritional benefits for farmers, their families and the local population (through increased food supplies). Irrigation can enable multiple cropping, which can smooth seasonal shortfalls in food supply and encourage the production of crops that contribute towards a more varied and nutritious diet. Indeed, continuation of the current decline in irrigation investment could eventually cause an increase in world cereal prices food prices, which would affect the poor in particular as a large proportion of their income goes on food.
in an inappropriate environment, e.g. where land is not evenly distributed, economic benefits of irrigation may be received predominantly by wealthy farmers and reinforce inequalities in the distribution of resources and wealth. The policy and institutional environments play critical roles in determining whether irrigation has positive impacts for poor people (FAO, 2003).