Peas biologically fix 55% of their N requirement, on average. This means N fertilizer is generally not required. N rates commonly applied with starter fertilizer blends (<15 lbs N/ac) may improve early growth before nodules begin fixing N, particularly on cold soils with low soil N reserves. Higher N rates can inhibit nodule development and N fixation.
Starter phosphorus (P) fertilizer has been shown to increase pea yields even on high P soils. Maximum seed-row safe rates are 20 lbs P₂O₅/ac with seed bed utilization (SBU) >15%. P fertilizer should be placed away from the seed-row with lower SBU. Potassium and sulphur fertilizers, necessary only on low testing soils, should be applied away from the seed-row as they cause more seed toxicity than P fertilizer.
Inoculate peas with Rhizobium leguminosarum bacteria, even on fields with a history of peas, to facilitate root nodule development and biological nitrogen (N) fixation.
Consider double inoculating fields with no history of peas or using a granular inoculant when seeding conditions are unfavourable (drought, excess moisture or acidic soils).
Inoculation strategies in peas are currently being investigated through the On-Farm Network, comparing single vs. no inoculation.