GROWTH, YIELD AND NODULE ACTIVITY OF PHASEOLUS-VULGARIS L AS AFFECTEDBY SOIL-MOISTURE

A study evaluated the response of two varieties of beans (Phaseolus vu lgaris L.) to different soil moisture levels during a dry season. The soil moisture regimes maintained throughout the growth period were fie ld capacity, 70-75 %, 50-55 % or 20-25 % available soil moisture. Plan t growth, yield and nodulation were optimal when plants grew at high s oil moisture levels. With increasing stress, all measured parameters o f both varieties were reduced. However, polebeans, with its vine type of growth was affected to a greater degree than bushbeans. In contrast , nodulation and nodule activity of both variables was affected by moi sture stress. A second experiment evaluated the effects of different s oil moisture levels over the growth cycle of bushbeans, which produce greater yields under drier conditions. The highest yields were obtaine d at higher moisture levels throughout the growth cycle. Moisture stre ss upto flowering reduced yields to a greater extent than when the pla nts were subjected to reduced soil moisture after flowering appearance . Some casual mechanisms of the results of the experiments and possibl e implications for incorporating this popular vegetable legume in rain fed agricultural systems are presented.