Field Pea Inoculation Trial

Bob Henson


A field pea inoculation trial was conducted to compare inoculant treatments submitted by commercial manufacturers / distributors to an absolute control (no inoculum, no N fertilizer) and a treatment with 60 lbs. total N (soil test + fertilizer) / acre.


The experiment was installed on a field with a loose history of field pea production.  A soil test the previous fall indicated 34 lbs NO3--N / acre in the top 24 inches.  The soil tested 12 ppm (Olsen) for phosphate, which is considered to be in the “high” range.  Cultivar ‘Integra’ (yellow-cotyledon) was sown at the rate of 300,000 live seeds / acre on 20 May in a randomized complete block design with six replicates.  Individual plots were 7 (7”) rows wide x 25’ long.


All inoculation treatments were numerically superior to the control in visual nodulation scores on 15 July and 15 of the 21 were significantly better (Table 1).  However, these differences were not translated into significant differences in days to end bloom or physiological maturity, plant height, lodging, test weight, or seed weight.



Pea yields were exceptional, with a trial average of 77.7 bushels / acre.  Although no differences were statistically significant (P<0.05), all but one inoculant treatment numerically increased yield.  Soil Implant, TagTeam Peat, Nitragin Experimental 2, SowFast Liquid, and N-Row yielded above 80 bushels / acre.  Of the 21 inoculants tested, 20 resulted in a 10 - 25% yield increase over the uninoculated control.