Modernization of spate irrigated agriculture: A new approach

Spate irrigation, a floodwater harvesting and management system, has for the past 70 centuries provided a livelihood for about 13 million resource-poor people in some 20 countries. Despite being the oldest, the system still remains the least studied and the least understood. It is only in the past two decades that the system has been subject to some modernization interventions, much of which focused on improving floodwater diversion efficiency. Effective floodwater diversion measures are necessary, but they must be supplemented with equally effective field water management and soil moisture conservation measures if sustainable improvement of land and water productivity is to be achieved. This paper draws on studies conducted in the past 5 years, particularly in the Republic of Yemen, Pakistan and Eritrea. The studies employed both qualitative and quantitative methods and assessed the modernization package that could result in lasting enhancement of crop productivity in spate irrigated agriculture. The suggested modernization measures include: avoid overstretching the command area; limit the number of irrigation turns to two or an irrigation gift of 1000 mm; avoid field bund heights of more than 1 m; adopt a field-to-field water distribution system instead of an individual field water distribution system; opt for water rights and rules that entitle downstream fields to the more frequent small and medium floods thereby ensuring equity in both water quality and quantity; optimize soil water-holding capacity and infiltration rate through pre-and-post irrigation tillage, combined tillage as well as soil mulching. Copyright © 2010 John Wiley & Sons, Ltd.