Ali A. Massoud, Mohamed M. El Kholy, Sayed A. El-Tohamy and Samir F. El Fiki
( 2010). Significance of N-biofixation and foliar spray with Zn and Co elements for improving faba bean productivity under field conditions of middle Nile Delta area, EgyptFayoum J. Agric. Res. & Dev., Vol.24, No.1, January, 2010
Abstract: A field experiment was conducted on a clayey soil during two successive winter seasons of 2007-2008 and 2008-2009 at Damas village, Mit Ghamer district, El Dakahlia Governorate, Egypt to evaluate the effectiveness of seed inoculation with rhizobium and foliar spray with zinc and cobalt on faba bean (Vicia faba L.) yield and its components as well as seed protein and nutrient contents. Zinc and cobalt sulphates were applied at three rates of 0, 250 and 500 mg L-1 for Zn and 0, 15 and 25 mg L-1 for Co. Yield and its components (i.e., number of tillers plant-1), number & dry weight of nodules and nitrogenase activity of root nodules plant-1 at two investigated periods of 45 and 70 days from sowing as well as number of pods plant-1, grain contents of protein and elements (i.e., N, P, K, Fe, Zn, Cu & Co). Soil content of available nitrogen forms (NH4+ and NO3-) after 70 days from sowing and at harvest were taken into consideration in this study. The obtained data show that seed inoculation with rhizobium inoculation and foliar spray with Zn and Co led to a significantly increased in each of tiller plant-1, number of pods plant-1, grain protein, grain and straw yields in kg fed-1. A parallel trend was occurred for the positive effect of the applied treatments on faba bean grain contents of N, K, Fe, Zn, Cu and Co, however, the greatest values were achieved at the highest rates of 500 and 25 mg L-1 of Zn and Co, respectively. On the other hand, no changes were observed for grain content of P by increasing the applied Zn and Co rates, may be due to the antagonism between Zn and P. As for the beneficial effects of the applied treatments on the available nitrogen content in the experimental soil, data show that seed rhizobium inoculation as well as Zn and Co as foliar application resulted in a noticeable increase for available content of nitrogen forms (NH4+ and NO3-) at both investigated periods of 70 days after sowing and at harvest as compared to the control treatment. At the same times, it is noticed that the available N-forms gave the greatest values at 70 days after sowing as well as in case of Zn foliarly as compared to at harvest and case of Co. This was true, since such increase was more closely to the nitrogenase activity. It is noteworthy to mention that seed inoculation and Zn or Co foliar application showed a parallel trend for the pronounced increases of all tested plant and soil parameters as compared to the control treatment under both studied growing season conditions. So, it could be said that the residual effect of N-bio-fixation in the soil after harvest leading to rationalize use of N-mineral fertilizers for the next crop, which is surplus point for sustainable agriculture system
Keywords: (Faba bean, N-biofixation, Zn or Co foliar spray, available nutrients )
