Water use efficiency of common bean and green gram grown using alternate furrow and deficit irrigation

The pressure on water resources in the Fergana Valley of Central Asia is expected to increase, as population and industrial activity grow. Increasing water use efficiency (WUE) associated with crop production is a way for and and semi-arid areas to increase their agricultural production where there is little or no prospect for expansion of water resources. The WUE of two water saving irrigation technologies were evaluated for two legumes, grown as a second crop, in the Fergana Valley of Uzbekistan. Conventional and alternate furrow irrigation and three irrigation schedules were used to irrigate food legumes in a field experiment conducted over two growing seasons (2003 and 2004) after winter wheat harvest. The treatments consisted of factorial combinations of three factors, organized following a split-plot randomized complete block design with four blocks: three irrigation schedules (recommended, moderate and severe depletions) as the main plot factor and combinations of the two irrigation strategies (conventional and alternate furrow irrigation) and two crops (green gram and common bean) as the two sub-plot treatment. The WUE was quantified for commercial yield, above ground biomass and root biomass per unit of water consumed by the crop. The results of this study indicate the WUE for both commercial yield and biomass were approximately twice as high for green gram as bean. Conversely, the water use efficiency for root biomass in bean (0.15 kg m(-3)) was slightly higher than in green gram (0.13 kg m(-3)). WUE increased in green gram when deficit irrigation or alternate furrow irrigation were practiced, whereas it remained constant in bean for all treatment combinations. These results suggest that common bean is not as well suited to water scarce conditions as green gram. Alternate furrow irrigation and deficit irrigation are appropriate methods to increase WUE, allowing application of less irrigation water, particularly, for green gram production. (c) 2006 Elsevier B.V. All rights reserved.