The biofertilising effect of seed dressing with PGPR Bacillus amyloliquefaciens FZB 42 combined with two levels of mineral fertilising in African cotton production

With the help of a field experiment, the influence of PGPR FZB42 (Bacillus amyloliquefaciens) seed dressing combined with a low (39 kg N/ha) and usual (79 kg N/ha) mineral nitrogen plant fertilisation on the cotton growth and yield was tested. The plant growth promoting rhizobacteria (PGPR) and the N-fertilisation alone promoted the plant growth, by the PGPR similar to the low N-fertilising. The cotton yield showed no significant difference between both treatments. The combined use of PGPR with different nitrogen plant fertilisation techniques resulted in the promotion of plant growth significantly compared to the mineral fertilising alone but differed significantly depending on the applied N-amount. The cotton yield in the combined application of PGPR and low N-amount increased by 75%. In combination with high N-fertilisation the yield increased by 30% compared to each of the N-fertilisation techniques. The effect was found to be based mainly on the PGPR growth promotion activity, resulting in larger plant root and stem–leaf system, increasing the possibilities to uptake available mineral nutrients. The great ecological value of the observed effectiveness improving influence by PGPR on the mineral plant fertilisation is discussed.