Effect of irrigation water cut-off position along furrows on water saving and productivity

Abstract

Despite being widely practised technique by smallholder farmers, cut-off technique continues to register low productivity and has not been adequately investigated to improve the status quo. This study aimed to investigate the scenarios to improve water use efficiency and productivity for the cut-off irrigation technique. Three cut-off treatments where water supply was stopped with the advance phases reaching 75%, 80% and 90% of furrow length were investigated with eight irrigation events. The crop grown under these scenarios was maize. Soil analysisshowed that in all the three subplots, the soils were sandy loam with an average of 69% sand and 31% silt. The initial soil moisture content was 14% and other corresponding moisture properties were 33.5 mm/hr infiltration rate, 9% permanent wilting point and 12% available moisture. Mean application efficiencies with significant differences (P<0.05) of 70%, 66.4% and 63% were achieved for the 75%, 80% and 90% length treatments respectively. Corresponding uniformities and water productivities of 90%, 89.9%, 89.2% and 1.54 kg/m3 , 1.38 kg/m3 , 1.18 kg/m3 respectively were obtained with no significant difference (P>0.05). The results demonstrated the 75% c u t - o f f has the potential of saving water of up to 26% without compromising water productivity. It is recommended therefore that the 75% cut-off position of water supply be promoted among the smallholder farmers and that research studies should now be carried out for less than 75% cut-offs