Soybean Response to Soil Rhizobia and Seed‐applied Rhizobia Inoculants in Wisconsin

Abstract

Seed-applied rhizobia inoculants can be used to promote biological nitrogen fixation in soybean [Glycitie max (L.) Merr.] production, yet their efficacy remains highly variable. The goal of this study was to improve the predictability of a positive soybean seed yield and quality response to inoculation by (i) characterizing inoculant product response in multiple environments, and (ii) quantifying the response of soybean to indigenous soil rhizobia populations. Two inoculants and a control were tested on three soybean varieties at nine locations in Wisconsin during 2009 and 2010. Soil samples were collected from each plot for the quantification of soil rhizobia. Seed yield, protein, and oil did not respond to inoculation across all 18 environments (P = 0.15, 0.38, and 0.30, respectively). Three environments responded positively to inoculation (P < 0.05), while the remainder showed no response. Yield of the control treatment was positively correlated with the soil rhizobia population level across all environments (P = 0.005), while the inoculated treatments showed no response. These data indicate a yield advantage for inoculation at lower rhizobia populations; however, given the large range of response with only three of 18 environments showing a positive response, a rhizobia population threshold to aid in the decision to treat soybean seeds with a rhizobia inoculant cannot be determined.

Indigenous rhizobia population influences the effectiveness of Rhizobium inoculation and need of inorganic N for common bean (Phaseolus vulgaris L.) production in eastern Ethiopia

“…The highest TBY produced in soils having low, medium and high rhizobial population were 3648.1, 4740.7 and 7222.2 kg ha −1 , respectively. The highest biomass in soil having high rhizobial population was previously confirmed by Furseth et al [48]. These authors found that yield of soybean positively correlated with soil indigenous rhizobial population across environments.…”

“…The highest PTTN was observed at low, medium and high rhizobial population and reached 3.24, 4.20 and 4.65 %, respectively. The highest PTTN could be attributed to a higher nodulation induced by the high rhizobial population and, thus, an enhanced N 2 fixation [38,48]. Due to synergetic effect of a starter N application on symbiotic N 2 fixation, the highest accumulated N in plants was recorded for the 20 kg N ha −1 application in soil having high rhizobial population [24].…”

Response of Soybean (Glycine max L.) to Rhizobia Inoculation and Molybdenum Application in the Northern Savannah Zones of Ghana

“…A study by [25] also confirms that soybean yield did not differ between inoculant products and the controls. The lack of significant grain yield response in the study sites could be attributed to the temporary drought experienced during plant growth and mineral nutrient deficiencies (N, P) which are the major constraints limiting legume N 2 fixation and yield [41].…”

Effect of Rhizobium inoculation to nodulation and growth of soybean [Glycine max (L.) Merrill] Germplasm

“…This symbiotic relationship will benefit both sides. According to Furseth et al (2012), soybeans can fixate 175 kg N per year in irrigated areas while in dry areas it is only able to slow as much as 100 kg N per year.…”