Rhizobium inoculant and seed-applied fungicide effects on field pea production

Abstract

Field pea has been shown to benefit from the use of rhizobium inoculation and seed-applied fungicides under intensive production. The objective of this research was to determine the effect of seed- or soil-applied rhizobium (Rhizobium leguminosarum bv. viciae) inoculants and seed-applied fungicides on field pea (Pisum sativum “Carneval”) production on fields with no previous history of the crop. The study was conducted at seven locations in Saskatchewan in each of 2 yr. Fungicide treatments were Apron FL (metalaxyl), Apron FL + Thiram 75WP (dithiocarbamate) and an untreated check in 1997 and a fourth treatment, Thiram 75WP, was added in 1998. Rhizobium treatments were seed-applied liquid inoculant, soil-applied granular inoculant and a non-inoculated check. Inoculation with rhizobium increased nodulation (5 of 10 sites), seed yield (6 of 13 sites), and protein content (3 of 8 sites), but occasionally appeared to reduce emergence (3 of 14 sites). Granular inoculant had more beneficial effects than the liquid inoculant. Fungicide treatments had few positive effects on production, and occasionally negative effects such as reduced emergence. Interaction effects were rare between seed-applied fungicide and seed-applied liquid or soil-applied granular rhizobium inoculants, which indicated compatibility of these products. Variability in the effects of inoculant types and fungicides suggests that responses are dependent on local soil and environmental conditions. Key words: Apron (metalaxyl), Thiram (dithiocarbamate), Pisum sativum, zero tillage