A preliminary evaluation of furrow inflow rate and cut-off time on the performance of smallholder raised bed farming systems

Abstract

Irrigated raised bed farming systems in north-west Pakistan are characterised by short furrow lengths (30 to 100 m), narrow bed widths (65 to 75 cm furrow spacing) and blocked ends. Wide beds (typically 130 cm furrow spacing) have recently been introduced and shown (Akbar et al. 2007) to produce agronomic benefits but are not in common usage. In general, 5 to 10 furrows are concurrently irrigated from small head channels with the time to cut-off determined by flow arrival at the end of the furrow and/or furrow filling. Management is often poor with varying furrow inflow rates, frequent overtopping of beds, problems with wetting front penetration (i.e. subbing) into beds and the potential for substantial deep percolation losses (Akbar et al. 2007). The purpose of this study was to evaluate the irrigation performance of narrow and wide raised bed systems under farmer managed conditions and to identify the potential to improve performance using simple irrigation management strategies.