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22 Jan 2009
Irrigation must be drained. If this stage is skipped, soils become salinated and harvest suffer, says Dr. Henk Ritzema, who has 28 years of experience in water management, mainly in South Asia. Ritzema has just gained a doctorate on the subject.
Irrigation water contains salt that stays in the soil when the water is absorbed by the crop and then evaporates. So some of the irrigation water should be used to rinse the soil and remove the salt. If this isn’t done, the land will be unusable for agriculture after some years. Both farmers and governments are keen to invest in irrigation, but they tend to forget some of the necessary investments because it takes a few years before the damage they prevent becomes visible. ‘Salination through poor drainage creeps up on you and is invisible for a long time, rather like erosion’, says Ritzema, who graduated on 16 January.
Drainage deserves more attention when irrigation channels are laid out, claims Ritzema. Everywhere he looked, he found better harvests when a good drainage system was in place. For wheat, good drainage even doubles the harvest. Besides timely investments, it’s important to involve farmers in discussing the requirements of the local soils, crop and farming methods. So Ritzema would like to see more participation by local farmers, and more flexibility instead of a blueprint approach. Researchers and designers should listen to local farmers more. A tricky issue, thinks Ritzema: ‘There’s always pressure in development cooperation to spend the budget and get visible results. Consulting farmers about the kind of drainage system that would suit them takes a lot of time and effort, but doesn’t get much of the money spent.’ / Joris Tielens
Dr. Henk Ritzema was awarded his PhD on 16 January. His supervisors were Bart Schultz, Professor of Land and Water Development at UNESCO-IHE in Delft, and Wim Cofino, Professor of Integral Water Management at Wageningen University.
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