with French bean crops indicated that irrigation when soil matric potential at 0.15 m depth reached -45 kPa resulted in highest dry matter production, green pod yield, nutrient uptake and water use efficiency (WUE) as compared to irrigations scheduled at-65 or-85 kPa. The difference in pod yield between irrigations scheduled at -25 and -45 kPa was not significant. Increasing soil moisture stress increased the canopy temperature and adversely affected plant water relations. There was a quadratric relationship between green pod yield and evapotranspiration (ET) with the yield-maximising ET ranging between 268 and 299 mm. Nitrogen fertilization significantly increased green pod yield, nutrient uptake and WUE but had no marked effect on water relations and canopy temperature.
French bean (Phaseolus vulgaris L.) is an important legume vegetable cultivated throughout India for its green pods. It has relatively shallow rooting depth, is a poor nodulator (Habbish and Ishaq 1974), requires frequent irrigations (Maurer et al. 1969;Miller and Gardner 1972;Stansell and Smittle 1980;Weaver et al. 1984) and large supplies of N fertilizers (Srinivas and Rao 1984). The increasing demands for limited water supplies in arid and semiarid regions coupled with rising costs of nitrogenous fertilizers necessitate economic application without adversely affecting production. Water requirement of French bean has received very little attention and, therefore, the purpose of this study was to evaluate the effects of soil matric potentials and N fertilization on plant water relations, canopy temperature, green pod yield, nutrient uptake and water use of French bean.