Role of Rhizobium, Organic fertilizer rates and Sulfur on Soil fertility, Nitrogen Balance and productivity of Broad Bean under South Sinai Conditions

Soil fertility is one of the major limiting factors for crop’s productivity in Egypt and the world in general. Biological nitrogen fixation (BNF) has a great importance as a non-polluting and a cost-effective way to improve soil fertility through supplying N2 to different agricultural systems. Faba bean (Vicia faba L.) is one of the most efficient nitrogen-fixing legumes that can meet all of their N needs through BNF. Therefore, understanding the impact of rhizobial inoculation and contrasting soil rhizobia on nodulation and N2 fixation in faba bean is crucial to optimize the crop yield, particularly under low fertility soil conditions. The efficiency of Rhizobium leguminosarum in enhancing nitrogen fixation and nutrient uptake in Faba bean and improving soil fertility. the field experiment were carried out at privet farm at tour city South Sinai Governorate, during the two consecutive winter seasons of 2018/2019 and 2019/2020. The experiments were conducted to study the effect of Rhizobium leguminosarum inoculation, organic manure, soil amendment i.e., 0; 25; 30 and 35m3/fed., and four rates of sulfur application i.e., 0; 100; 150 and 200 kg/fed., on growth, productivity, nodulation, soil microbial counts, enzymatic activities, soil total N, P, K, Fe, Zn and Mn, soil chemical properties (pH and EC) and Nitrogen balance of broad bean, Aspany F1 cv. grown under sandy soil conditions. Results revealed that organic manure at the rate of 30m3/fed which is superior significantly plant yield and total yield (ton/fed) followed by organic manure at the rate of 35m3/fed. No significant differences occurred between these two organic treatments in both seasons. Sulfur amendment at the rate of 200 kg/fed followed by the rate of 150 kg/fed had the highest values and significant increases on plant weight; number of branches/plant; plant yield; total yield (ton/fed), there are no significant differences between both treatments in both growing seasons. While, each of the study factors had an individual significant effect on total microbial counts, enzymatic activities (Dehydrogenase and Nitrogenase), nodule No., nodule N%, nodule dry weigh, soil total nitrogen, phosphorus, potassium, Fe, Zn and Mn, soil chemical properties (pH and EC) and Nitrogen balance. But combined treatment organic manure 35m3/fed + sulfur at the rate of 200 kg/fed with rhizobial inoculation gave highest values on all most traits in both seasons.