Response of Green Bean to Fertilization with Potassium and Magnesium

Two field experiments were carried out during the two successive growing seasons of 2004/2005 and 2005/2006 in the experimental farm of EL-Bousialy Protected Cultivation Site, El-Behaira governorate, Egypt, to study the effect of different levels of potassium (48, 72 and 96 kg K2O /fed.) and magnesium (0, 3 and 6 kg MgO/fed.) on the growth, yield and quality of green bean (Phaseolus vulgaris L.) cv. Paulista. With respect to the effect of potassium application, plant growth characters, i.e., plant height, number of leaves and branches, fresh and dry weight and total chlorophyll, as well as green pod yield (early, local, exportable and total green pod yield) and pod quality, i.e., pod length, thickness, fibers content, TSS%, total protein percentage, were increased by increasing the level of K fertilizer from 48 up to 96 kg K2O/fed. Respecting the effect of Mg application, the results clear that the vegetative growth of snap bean plants and green pod yield as well as pod quality were improved by increasing the level of Mg fertilizer from 0 to 6 kg MgO / fed. Respecting the effect of the interaction treatments, result clear that all vegetative growth parameters, green pod yield and its components were significantly affected by the interaction between potassium and magnesium application. The highest values were recorded with the highest levels of potassium and magnesium. As for pod quality, pod length, thickness and fiber were not significantly affected by the interaction treatments. However, TSS and total protein contents were significantly increased with increasing the levels of potassium and magnesium application up to the highest levels.