Effect of nitrogen fertilization and rhizobium inoculation on growth and yield of two soybean (Glycine max (L.) Merrill.) cultivars

A field experiment was conducted for two consecutive seasons (2004/05 and 2005/06) on the Demonstration Farm of the Faculty of Agriculture at Shambat, to study the effect of nitrogen fertilization and rhizobium inoculation on growth and yield of two soybean (Glycine max 1. Merrill) cultivars. The experiment was laid out in a randomized complete block design with four replicates. The cultivars used were Giza22 and Gizall1. The nitrogen treatments consisted of N0(control), N1 (9.3 kg/ha urea) and N2 (18.6 kg/ha urea). The seeds of both cultivars were either non inoculated (R0) or inoculated with Rhizobium japonicum strain TAL 110 before sowing (R\}). Characters studied included: growth attributes (plant height, number of branches per plant, number of leaves per plant, leaf area index, number of nodules per plant and nodules dry weight (g) per plant),phenological attributes (number of days to 50% flowering, number of days to first pod, plant height to first pod and number of days to physiological maturity), yield attributes (number of pods per plant, number of seeds per pod, 100- seed weight (g), seed yield (g) per plant, seed yield per unit area, dry matter production (ton/ha) and harvest index), and seed chemical composition (protein content and oil content). The results showed that nitrogen fertilization had insignificant effects on all attributes measured in this study except number of branches and seed yield. On the other hand, rhizobium inoculation had significant effects on number and dry weight of nodules, dry matter production, number of pods per plant, number of seeds per pod and seed yield. The differences between the tested cultivars on most of the parameters measured in this study were significant. In this regard, the cultivar Giza22 matured earlier, had more number of pods per plant and higher seed yield than Giza lll cultivar. In contrast, all treatments had insignificant effect on seed chemical composition (protein and oil content) tested in this investigation