Extensive fild responses of dryland crops inoculated wiyh a liquid formulation of Azospirillum brasilense

DÍAZ-ZORITA, MARTÍN; SMITH, R. STEWARD; OSBURN, ROB M.

Milwaukee, WI

Conferencia; The 20th North American Symbiotic Nitrogen Fixation Conference; 2007

Shoot and root changes, moderate free nitrogen fixation and other multiple mechanisms of inoculated plants with Azospirillum brasilense under a variety of environmental and soil conditions have been previously described. The objective of this study was to quantify the effects of on-seed or in-furrow inoculation with a liquid formulation of Azospirillum brasilense strain INTA Az39 on growth and yield production of alfalfa, barley, canary seeds, corn, cotton, oat, rye, triticale, rice, sorghum, sugarcane, sunflower and wheat crops in North and South America temperate dryland agricultural environments. The study was performed between the 2002/03 and 2006/07 growing seasons in more than 450 experimental sites. Under the studied conditions, the application of this liquid formulation of Azospirillum brasilense provided an increase in the vegetative growth and yield of the crops. For example, the inoculated wheat accumulated 12 % and 14 % more shoot and root dry matter at tillering than untreated wheat. The leaf and grain nutrient contents were also greater in the Azospirillum treatment and, in terms of grain yield components, greater responses were observed in the number of grains per unit area than in the single grain weight. For all the studied crops, the mean yield response to the inoculation with Azospirillum brasilense was 7.9 %. The mean agronomic efficacy (relative number of sites with positive responses) for wheat and corn was of approximately 75 % and 85 , respectively. The described effects on crop productivity and yield were independent of the crop management practices (ex. N and P fertilization, fungicide treatments, etc.) and regions.