The ammonium excretingAzospirillum brasilensestrain HM053: a new alternative inoculant for maize

Aims We evaluated the effect ofAzospirillum brasilensestrain HM053 inoculation on maize seeds, a spontaneous mutant that excrete ammonium and fix nitrogen constitutively. Methods Maize was grown with different nitrogen (urea) concentration and inoculated withA. brasilenseAb-V5 (Brazilian commercial strain) or HM053 strain in four field experiments, in three regions of Parana State, Southern Brazil. We evaluated yield components, nutrient content on leaves and grains and productivity during the crop cycle. Results Inoculation withA. brasilensestrain Ab-V5 and HM053 associated with base fertilization (30 kg ha(-1) N) improved crop yield in all trials. Ab-V5 increased production between 2.2 to 10.4%, or 178.0 to 759.9 kg ha(-1), respectively. HM053, by itself, increased production between 4.7 to 29%, or 460.5 to 1769.3 kg ha(-1), respectively. Conclusion The new strain HM053 showed to be a great biofertilizer for maize seeds and a new alternative for a more sustainable agriculture.