World Water Day arrives every 22nd March. For me, it’s time to reflect on the relationship between rice and water.
Two of the world’s most precious commodities that are so intimately linked. The world produces some 700 million tons of paddy rice each year. This is enough to provide the staple food for more than three billion people, of which some 700 million live in poverty.
The majority of rice is grown under irrigated conditions in which the fields are flooded from planting to harvest. Because of this flooding, rice is said to use a lot of water, about two and a half times the amount of water needed to grow a crop of wheat or maize.
To ensure good yields, farmers and governments throughout the centuries (even millennia!) have developed irrigation infrastructure.
And, since there are some 160 million hectares of planted rice land, rice has become the biggest single user of “developed” fresh water worldwide. Using some simple calculations, I once estimated that all the rice land receives 35–45% of all the world’s irrigation water (which itself uses some 70% of all the world’s developed water resources).
Thus, rice is often portrayed as a “profligate” user of water
The elements of SRI include: transplanting young seedlings, before the start of their 4th Add to dictionary of growth; reducing plant populations by as much as 80-90% per m2; converting paddy soils from anaerobic, flooded status to mostly aerobic conditions, by alternate wetting and drying; active soil aeration, with mechanical welders; and increased soil organic amendments. While some of the practices appear counterintuitive – getting more production from fewer plants, with less water application, and with reduced reliance on chemical fertilizers – the beneficial effects of each practice can be explained and justified scientifically (Uphoff, 2008). The principles of SRI, which are fundamental to achieving the expected benefits, get translated into certain practices, adapted in their fine points to local conditions