RESPONSE OF SNAP BEAN (PHASEOLUS VULGARIS L.) TO SOIL MOISTURE CONTENT AND NITROGEN FERTILIZATION UNDER SANDY SOIL CONDITIONS

Two field experiments were carried out at the Experimental Farm of the
Faculty of Agriculture, Suez Canal University, Ismailia, Egypt during the two spring
successive seasons of 2003 and 2004 to investigate the effect of available soil
moisture content (ASMC) of 40 %, 60% and 80% of the available water and nitrogen
levels (0, 40 and 80 kg N.lfed). on vegetative growth measurements, number and
weight of pods/ plant and yield/ fed. Photosynthetic pigments and chemical contents
of snap bean (Phaseo/us vulgaris L.) under sandy soil conditions.
Vegetative growth parameters (plant height, number of branches, shoot fresh
and dry weights and leaves area, per plant) were significantly increased as available
moisture or nitrogen rates increased. The interaction effect of the two factors showed
that the highest values of all parameters were obtained from 80 % ASMC and 80 kg N
/fed. Similar results were obtained for relative growth rate (RGR) and net assimilation
rate (NAR)
Yield and its components (number of pods, fresh weight of pods / plant and
yield of green pods/ fed.) were increased with increasing of the available soil moisture
or nitrogen application. The interaction revealed positive significant effect and the best
yield was obtained from plants subjected to 80 available water % and.80 kg N/ fed.
The leaves contents of chlorophylls a, b, total chlorophyll and carotenoids
were increased with decreasing available soil moisture or increasing nitrogen level.
On the other hand NPK and carbohydrate contents were significantly increased with
increasing both available soil moisture content and nitrogen levels.