IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...

17 th International Congress on Nitrogen Fixation
Fremantle, Western Australia
27 November – 1 December 2011
Session Details: Wednesday 30 November 2011
Concurrent Session 14 – Cyanobacteria & other organisms
1600 - 1740
Authors: Faten Mohamed, Soha Mostafa, & Nabil Omar
Soils, Water and Environ. Res. Inst., Agric. Microbiol. Res. Dept., ARC, Giza,
Egypt.
Presentation Title: Influence of beneficial microbes and proline treatments on sugarbeet under nitrogen
limitation in saline-sodic soil
Presentation Time: 1600 – 1620
A field experiment on sugar beet (Beta vulgaris L.) yield and yield quality under saline-sodic soil conditions
was conducted at Sahl El-Hussinia Res. station, El-Sharkia Governorate, Egypt, during the winter season of
2008/2009. The influence of cyanobacteria and N2-fixing bacteria were compared either individually or in
combination to supplementation with proline amino acid under two levels of mineral nitrogen fertilization (50
and 75% of nitrogen recommended dose). Soil enzymatic activities (dehydrogenase and nitrogenase), total
bacterial counts, total cyanobacteria counts and total nitrogen fixing bacteria counts were enhanced by the
biofertilizers compared to proline treatment and control, particularly when the combined inoculum of
cyanobacteria and N2-fixing bacteria was applied in the presence of 75% N. In addition, inoculation with
cyanobacteria and N2-fixing bacteria, either individually or in combination with 75%N, led to a slight decrease
of pH and EC values of saline soil, while there was an increase in the availability of NPK as compared with
control plots.Proline and biofertilizers showed a significant positive impact on some physiological properties of
plants drown at 75% nitrogen level, such as chlorophyll in leaves, proline and phenolic compounds in roots.
The highest responses for these traits were in proline-treated plots followed by the combined inoculation of
cyanobacteria and N2-fixing bacteria. While, there was no significant difference in root yield productivity
between proline treatment and the combined inoculum of cyanobacteria and N2-fixing bacteria with 75%
nitrogen fertilizer. The combined inoculation positively increased N, P and K uptake and decreased the uptake
of Na in roots. The combined inoculum of cyanobacteria and N2-fixing bacteria with 75% nitrogen led to a
significant increase in shoot and root dry weight as well as root yield quality (sucrose and purity). Results
suggest that the beneficial effect of the cyanobacteria and N2-fixing bacteria on sugar beet growth, yield and
yield quality was attributed to the biologically active substances produced by these microbial strains besides
the nitrogen fixation of the diazotrophs which compensate the reduction of the costly and the environmentally
polluted mineral nitrogen fertilizers in the new reclaimed saline-sodic soil.
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