Responses of cowpea (Vigna unguiculata (L.) Walp.) and mung bean (Vigna radiata (L.) Wilczek) to irrigation

Summary Cowpea and mung bean were subjected to three irrigation schedules during summer dry months (May–June). In general, cowpea had higher rates of net photosynthesis (P _n ,Figs. 1, 2), dark respiration (R _d ,Table 1), absorption of photosynthetically active radiation (PAR, Table 2), and growth (Fig. 7) than mung bean. Mung bean reflected more PAR and maintained a slightly cooler canopy than cowpea (Table 2). Moisture stress decreased P _n , R _d ,absorption coefficient of PAR, evaporative cooling and growth in both the species. However, the reductions in P _n rates of stressed leaves were more than the decreases in R _d .Restoration of water supply to stressed cowpea resulted in a more rapid recovery of growth as compared to mung bean.     

Irrigation management practices for maximizing seed yield and water use efficiency of Othello dry bean (Phaseolus vulgaris L.) in southern Alberta, Canada

A 2-year study was carried out from 2006 to 2007 to determine the most suitable irrigation management for maximum dry bean (Phaseolus vulgaris L.) seed yield and water use efficiency (WUE) in southern Alberta, Canada. Six irrigation management treatments were evaluated in this study, including scheduling irrigation based on soil water depletion within a 0.30-m root zone, a 0.60-m root zone, and a split 0.30/0.60-m root zone (a 0.30-m root zone during vegetative growth stages and a 0.60-m root zone at flowering), and 12, 25, and 50-mm applications of irrigation water based on soil water depletion in a 0.60-m root zone. Plant available soil water was maintained above 60% in all irrigation management treatments. A significant increase in average seed yield (15% in 2006 and 46% in 2007) and in WUE (30% in 2006 and 50% in 2007) was found in more frequently irrigated treatments (0.30-m root zone, split 0.30/0.60-m root zone, and 12-mm application) compared to less frequently irrigated treatments (0.60-m root zone and 50-mm application). Dry bean seed yield and WUE may be maximized by keeping the majority of roots moist.