Manage Nitrogen Fertilization in Cereals Using PGPB Strains

The inoculation of crops with growth-promoting bacteria is an interesting alternative to be considered to reduce the intensive use of chemical fertilizers in agriculture. This experiment is being conducted to test the effect of Plant Growth Promoting Bacteria (PGPB) on the growth and yield of oats and durum wheat grown with minimal nitrogen inputs. Three Rhizobium spp. strains, namely (L1, L2 and L3) isolated from root nodules trapped with Lupinus albus L. were used to assess the germination and growth of these crops. In a second step, these strains were tested on durum wheat grown under different nitrogen fertilization treatments (without nitrogen fertilization, applying 50 and 100% of the recommended nitrogen doses). Results revealed that inoculation with the different strains does not affect the germination percentage of oats and wheat seeds. However, compared to the control, the L2 and L3 strains significantly improved the above-ground biomass of tested crops. The L3 strain is particularly beneficial to the root development of wheat. The wheat inoculation at different nitrogen rates and under optimal fertilization conditions (100%) showed an improvement in number of spikes/plant, while the strain effect is particularly observed at the fertilization level of 50% of the recommended dose. At this rate, the L2 strain was particularly efficient and allowed equivalent yields at 100% fertilization levels for the parameters: shoot dry weight, number of spikes/plant, number of grains/spike and straw weight. This investigation highlighted that the use of PGPB in cereals is a promising practice and contributes to the reduction of chemical inputs and improved farmers’ profits.