Wednesday, July 25, 2012

The Battle for Water - Harvesting and conserving rainwater key to boosting crop yields

In its Rio+20 call for action, CGIAR urged Rio+20 actors to address the unequal sharing and unsustainable use of natural resources such as water and land, through improved governance and technology dissemination. World food production, hence food security depends on water but water availability per capita is drastically decreasing.

To sustainably ensure a steady food production especially in poor smallholdings in the (global) south, mainly practicing rain fed agriculture, one priority is to help local rural communities better manage “green water” – the rainwater captured by the soil and available for plants.

For decades the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) has been working on successful local and farmer participatory water governance models.

Whether it's bread, meat, milk or bananas, whatever we eat demands water. But with a rapidly growing population (already more than 7 billion people), water availability gets more and more scarce.

There is a correlation between poverty, hunger and water stress. The UN Millennium Project has identified the "hot spot" countries in the world with the highest number of malnourished people.

These countries coincide closely with semi-arid and dry sub-humid hydroclimates, savannahs and steppe ecosystems, where rainfed agriculture is the dominating source of food, and where water constitutes a key limiting factor to crop growth.

The Food and Agriculture Organisation (FAO) estimates that we need to increase agricultural production by 70% to feed the projected 9 billion people expected on the planet by 2050. But, given the current global food crisis, boosting agricultural production will certainly increase water stress.

PRODUCING MORE WITH LESS WATER

We urgently need to increase water productivity. But how do we produce more cereals, milk and bananas with less water? And what type of water are we talking about?

At the last World Water Forum in Marseille in March, experts talked about the colour of water: blue water (irrigation), green water (rainwater captured by the soil and available for plants) and grey water (polluted water that could be treated and recycled). More