Effect of Rhizobium inoculant, Nitrogen Starter and Cobalt on Stimulation of Nodulation, N Fixation and Performance of Faba Bean (Vicia faba L.) Grown under Salinity Stress

Abstract

In the modern agriculture systems, there is a general tendency to reduce the amounts of mineral nitrogen inputs and maximize their use efficiency to minimize environmental pollution and its hazards on public human health. It is well known that cobalt is a necessary trace element to leguminous crops and bacterial communities responsible for biological nitrogen fixation (BNF). So, two field trials were performed in a split-split-plot design with three replicates during two-successive winter seasons of 2019/2020 and 2020/2021 as the sake of studying the influence of Rhizobium inoculant, nitrogen application rates [100, 75 and 50% of nitrogen recommended dose (NRD) as starter, equivalent to 20, 15 and 10kg N fed-1 , respectively] and cobalt supplementation (seeds soaking and foliar application as combined method) at different concentrations of cobalt (0.0, 8.0 and 12.0 mg cobalt L-1) on nodulation, nitrogenase activity and performance of faba bean plants grown on saline clay soil. Findings of this study showed that plants inoculated prior to sowing with the strain of Rhizobium at rate of 10 g inoculant per 1.0 kg seeds under N fertilization at rate of 15 kg N fed-1 with cobalt treatment at rates of 8.0 and 12.0 mg cobalt L-1 realized better results than that fertilized with ammonium sulphate at rate of 20 kg N fed-1 without both Rhizobium inoculation and cobalt treatment. Generally, cobalt treatments improved nodulation, nitrogenase activity and stimulated nodulation parameters, thus enhancing all studied growth criteria, green yield and its components of faba bean plants grown under salinity stress.

Impacts of cobalt and zinc on improving peanuts nutrient uptake, yield and irrigation water use efficiency under different irrigation levels

“…This was partly due to reduced nutrient availability under higher pH and competition between these nutrients for transport sites in the root, leading to a reduction in photosynthesis, consistent with previous findings 21 , 22 . These detrimental effects ultimately reflected in the reduction of peanut agronomic traits, peanut yield, and IWUE, which align with previous studies 70 – 72 . Dang et al 73 also highlighted that plant growth and metabolism vary based on the concentration and state of Co in the rhizosphere and soil.…”

Maximize faba bean productivity under salinity conditions

“…Additionally, salinity stress affects seed quality, decreasing protein and starch levels while increasing salt concentration. However, the implementation of appropriate management practices can mitigate the harmful effects of salinity stress on faba bean (Baddour et al 2021).…”

Drought Stress Effects on Vegetable Crop Productivity: Melatonin's Mitigating Role and Rhizobium Inoculants for Enhanced Nitrogen Fixation under Water Scarcity

“…The results demonstrated that applying cobalt at a rate of 30 mg L -1 yielded the most favorable outcomes in terms of growth, yield attributes, nodule number, nodule weight, and grain yield. In the research by Baddour et al (2021), the combined effect of Rhizobium inoculation, nitrogen application at different rates (100%, 75%, and 50% of the recommended dose), and cobalt supplementation at varying concentrations (0.0, 8.0, and 12.0 mg cobalt L -1 ) was examined using a combined method of soaking and foliar application. The best results were achieved when plants were inoculated with a specific Rhizobium strain, nitrogen was applied at a rate of 15 kg N fed -1 , and cobalt was treated at rates of 8.0 and 12.0 mg cobalt L -1 .…”

“…Insufficient Mo levels can lead to reduced nodulation and nitrogen fixation, as discussed by Gericó et al (2020). Co and Mo are essential for the vitamin B12 required synthesis for hemoglobin formation in nodules, therefore success N fixation (El-Sherpiny et al 2021). The relationship between copper (Cu) requirements for symbiotic nitrogen fixation and its role in plant growth is not well-defined.…”