Influence of beneficial microbes and proline treatments on sugar beet under nitrogen limitation in saline-sodic soil

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 N[2]-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 controls, particularly when the combined inoculum of cyanobacteria and N[2]-fixing bacteria was applied in the presence of 75% N. In addition, inoculation with cyanobacteria and N[2]-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 N[2] fixing bacteria, while, there was no significant difference in root yield productivity between proline treatment and the combined inoculum of cyanobacteria and N[2] fixing bacteria with 75% nitrogen fertilizer. The combined inoculation positively increased N, P and K uptake and decreased the uptake of Na in roots. Also, the combined inoculum of cyanobacteria and N[2] 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 N[2] 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

Impact of biofertilizer and elemental sulphur on growth and yield of wheat [triticum aestivum var.] grown in saline sodic soil

Two field experiments were carried out at Sahl El-Hossainya Research Station, El-Sharkia Governorate during winter seasons [2007-2008] and [2008-2009] to study the effect of salt tolerant N[2] fixers, Azospirillum Azospferum, Azotobacter chroococcum, Bacillus polymyxa and Klebsiella penumoniae as well as plant growth promoting rhizobacteria [Pseudomonas fluorescens and Bacillus subtilis], on soil biological and chemical properties as well as growth and yield of wheat cv. Sakha 93, grown in saline sodic soil amended with elemental sulphur [0.5 ton/fed] and two levels of inorganic N-fertilizer [75 and 100% of the recommended dose]. Results indicated that inoculation with a mixture of N[2] fixers+PGPRs in presence of 0.5 ton/fed elemental sulphur and 75% of the recommended dose of N-fertilizer, resulted in superior improvement of enzymes activities [nitrogenase and dehydrogenase], CO[2] evolution, growth parameters [plant height, plant dry weight and No. of tillers] and chlorophyll content in leaves at 80[th] day of wheat sowing. At harvesting, the same treatment recorded the optimum NPK, total amino acid and crude protein contents in grains, and the highest grain yield, straw yield and weight of 1000 grains comparing to uninoculated and control treatments. Also, the same treatment recorded improvement in some soil chemical properties [pH, EC and available NPK]. So, our study supports the use of biofertilizers and chemical amendment [sulphur] as beneficial source for sustainable agriculture specially in saline sodic soil under reclamation