More Crop per Drop Revisited

In 1996 David Seckler, then recently appointed Director General of IWMI with a mandate to re-focus the research agenda of the institute, published the first IWMI Research Report (Seckler, 1996). This brief note contained many of the basic ideas that have come to characterize what has been coined "the IWMI approach to water for agriculture". It was, In essence, a research agenda around the following three ideas:

1. Basin focus: As renewable water resources available for human use become fully committed in a basin, and competition among user's increases, the appropriate focus for water management is the basin level, not the field, farm or even the irrigation system level. This concept is closely linked to the idea of open, closing and closed basins – where a basin is defined as ‘closed', when there is no usable water leaving the basin;

2. Recycling: Many of the water savings achieved at field level may only capture water that would otherwise have been re-used downstream. These are not real water savings, where additional supplies become available ("wet" water savings), but simply a re-allocation of water from downstream to upstream users ("dry" water savings). With this idea comes a focus on the fate of water through recycling and re-use;

3. Crop water productivity: Rather than focusing on the potentially misleading idea of increasing irrigation efficiency, the focus should be on increasing water productivity – in essence, the output produced per unit of water consumed. This gave rise to the phrase "more crop per drop".

These ideas, described in more detail below, formed the core of the IWMI research agenda in the 1995-2000 periods, culminating in the key publication on water productivity by Kijne et al., Eds (2003).

Conclusions

The primary conclusion of this work, as presented in a widely cited IWMI Research Report (Seckler et al., 1998) and later summarized in Seckler et al. (2003), was that:

The "basic IWMI scenario" was published as the IWMI Contribution to the World Water Vision (Cosgrove and Rijsberman, 2000). Its major findings and recommendations were (IWMI 2000):

1 . The world's primary water supply will need to increase by 22% to meet the needs of all sectors in 2025.

2 . Seventeen percent more irrigation water will be needed for the world to feed itself in 2025.

3 . Nearly one-third of the populations of developing countries in 2025, some 2.7 billion people, will live in regions of severe water scarcity.

4 . The global community must invest in research to improve crop water productivity (crop per drop).

5 . New water infrastructure will have to be developed to meet future food requirements.

6 . Groundwater reserves will be increasingly depleted in large areas of the world.

7 . Salinization of soils, compounded in many cases by increasingly saline or poisoned groundwater, will seriously affect land that has been highly productive in recent decades.

8 . The people most affected by growing water Scarcity will continue to be the poor, especially rural poor; and among poor people, women and children will suffer most.

9 . Better use of water in several large, internationally shared river basins can contribute significantly to achieving food security and reducing poverty in developing countries.

Seckler believed that while the solution to water scarcity was to enhance water productivity in irrigated agriculture as much as possible, further development of water supplies for irrigation to meet future food demands was inevitable and would require the widely-cited "17% of additional water for irrigation by 2025". He did not believe there was much potential to improve water productivity in rain fed agriculture. This assumption that the increase in water productivity in rain fed agriculture would be low is a key factor in the relatively high estimate of a 17% growth in irrigation water demands.

1. It underplays the importance of water quality; the emphasis on potential re-use of the fraction of the water that is not consumed appears to suggest that such re-use can take place without a cost. However, virtually all water withdrawal and application leads inevitably to at least some quality degradation (salinization and other pollution) and costs energy. This explains IWMI's preference to measure water demands by their evapotranspiration, while others maintain a preference for water withdrawals as the key indicator.

2. The crop-per-drop concept does not accommodate the non-crop water outputs, fisheries and environmental services to the other multiple values water serves (from domestic water use to livestock watering). The implication is that while at farm or field level, the focus on crop water productivity can often be justified, on larger scales a broader definition of water productivity, which incorporates all values associated with water use, is needed. Only such a broader definition will serve the management of water across the many uses within a basin.

3. The implicit emphasis on irrigation of crops through renewable water resources, i.e., the part of the water cycle that runs off into rivers and recharges groundwater, (also called "blue water"), tends to underestimate the importance of the other 60% of the hydrological cycle that is stored as soil moisture, (the so-called "green water"). Through the growing importance of groundwater irrigation, small scale irrigation, rainwater harvesting and supplemental irrigation, the once sharp boundaries between rain fed and irrigated agriculture have largely disappeared. This requires a new, unified approach that examines the whole hydrological cycle and looks at water Management for agriculture across the rain fed-irrigated spectrum.

4. Increasing water productivity is no more than a means to an end. One key objective is the reduction of poverty and hunger. Increasing water (and land) productivity may well be a significant factor in alleviating poverty in communities strongly dependent on access to productive land and water resources. It cannot be said, however, that improving water productivity will by definition have a positive impact on poverty, since access to resources (and the distribution of any net benefits) also plays a determining role in the final analysis.

5. Similarly, another often linked objective is the sustainable use of natural resources, i.e., the arrest or rehabilitation of resource overuse (groundwater depletion) and degradation (soil erosion or salinization). Increasing water productivity is unlikely to halt over-use of water locally. Indeed, it may in fact encourage resource intensification, as it is likely to increase the profitability of the farmer, whose productivity has increased. On a larger scale, assuming that the total demand for a given product or service stays constant, increased productivity in one location ought to displace water use at a lower productivity elsewhere, but not necessarily increase the Sustainability of the resource use in the basin or sub basin, where the productivity is increased.

Addressing the Limitations

In the period 2000-2005, IWMI addressed a number of the limitations discussed above as follows:

1. The balance between water for food and water for nature has become the core issue on the agenda, and IWMI has re-focused its research around the so-called water-food environment Nexus (Rijsberman and Molden, 2001; Rijsberman and Mohamed, 2003; Rijsberman and de Silva, 2004).

2. The linkages between water and land, salinization and soil degradation, water and land quality, nutrient cycling, and re-use of wastewater in peri-urban agriculture have become a central focus of IWMI's work (Scott et al. eds., 2004).

3. The improvement of water productivity across the entire blue-green, rain fed-irrigated, surface-groundwater spectrum has become the norm in the institute's work (Noble et al., 2004). This has also led to a re-assessment of the potential to improve water productivity in rain fed agriculture.

4. Assessing the impact of water productivity on the alleviation of poverty and hunger has become a central theme in IWMI's work as well (e.g., Maria Saleth, 2003).

Five themes were introduced with IWMI's 2000-2005 Strategic Plan:

1. Agricultural Water Management

2. Sustainable Land and Water Management

3. Groundwater Management

4. Water Resources Institutions and Policies

5. Water, Health and Environment

Each of these themes, their focus and research contributions are described in more detail in the following five summary articles.

Tightening up: the new focus

An external review of IWMI's work, (Wright et al., 2003), and the CGIAR Science Council review of the Challenge Program on Water and Food in 2004, motivated the development of A new, tighter conceptual framework. This is intended to provide a cleaner structure that will allow a sharp focus of the institute's work on its final objectives, i.e., contributing to the Millennium Development Goals related to, primarily, reduction of poverty and hunger and sustainable use of the environment. Briefly, in this new framework IWMI's work falls into four blocks or activities.

1. Mapping water productivity (WP): to assess water (and land) productivity at basin level for key crops, (as well as combinations of crops and complementary livestock/fishery outputs, livelihood strategies, and environmental values), spatially disaggregated (to a useful level) across the basin; and to analyze the key variables that explain WP variations, (including soil/land Degradation). The key idea is not to suggest that water productivity is a solution, but rather that it provides a valuable framework for understanding productive land and water use.

2. Mapping water poverty (WPv): to assess spatial patterns of poverty and poor people's access to productive land and water resources throughout the basin. The basic idea is not to presume that increasing water productivity will alleviate poverty, but rather to identify the target Group that could benefit from improved access to productive land and water resources.