Abstract

                                The effect of concentration and source of added nitrogen (N*H_{1}) and N*O_{2} ) on nodulation, nitrogen fixation. yield and content of N. P. K. Ca and Mg of soybean (Glycine max (L.) Merr.cv.Amsoy) were studied in nutrient solution medium. Nodulation and nitrogen fixation were severely suppressed by the addition of nitrogen source either N*H_{1} or mathbb NO 3 , The degree of suppression was more pronounced in the presence of N*O_{3} than NH, and the reduction of nodulation and nitrogen fixation was more intensified at later stages of soybean growth. Addition of N*H_{1} decreased the dry weight of roots whereas fN*O_{2} increased it and the production of tops followed the same pattern for the two forms of nitrogen studied. By the increase of NH, concentration in nutrient solution. N and P contents were found to increase in the roots and shoots while there was a reduction in the content of aleph 1 Ca and N*t_{0} Unlike aleph H_{mu} N*O_{3} increased the uptake of cations as well.

Key words :