Bund preparation and its maintenance
Good bunds are a prerequisite to reduce seepage and underbund loses of water. Bunds should be well compacted and any cracks or rat holes should be plastered with mud at the beginning of the crop season. To avoid overbund flow during heavy rainfall, bund height should be at least 20 cm. Researchers have used plastic sheets in bunds in field experiments to reduce seepage losses which are probably financially not feasible to farmers.
One of the recently proposed innovations to deal with water scarcity in the rice wheat system in the Indo Gangetic Plain is the use of raised beds. In the system of raised beds, rice is grown on beds that are separated by furrows through which irrigation water is coursed. Though dimensions may vary, beds are usually around 35 cm wide, separated by furrows that are 30 cm wide and 25 cm deep. Rice can be transplanted or direct seeded on the beds. So far, the raised bed system has mostly been tested with current lowland rice varieties, and yield gains can be expected when suitable aerobic varieties are developed/used. Tractor-pulled equipment has been developed that shaped the beds and drills seed (sometimes together with fertilizers) in one operation.
Among the suggested benefits of raised beds are improved water use and nutrient use efficiency, improved water management, higher yields, and when the operations are mechanized reduced labor requirements and improved seedling and weeding practices. In the Indo Gangetic Plain, farmers are experimenting with raised beds for rice and other crops with different degrees of success. More information on raised beds can be obtained from the Rice Wheat Consortium (www.rwc.cgiar.org/index.asp).