Cover crops: field peas

Description

Family

• Winter annual legume
• Pisum sativum L.

Growth habits

Germination

• Large, spheroidal-shaped seeds
• Germinates best in cool (4.5°C) moist — yet well-drained conditions
• Germination is higher at warmer (24°C) temperatures — but seeds are at a higher risk of infection from soil-borne diseases

Top growth

• Viney, growth with weak stems — may reach a height (or length) of 1 m
• Growth is rapid under cool conditions
• Requires a supporting crop (like oats or rye) to stand
• Flowers in pairs - white, pink or purple

Root system

• Shallow root system
• Susceptible to drought

Overwintering

• Can withstand freezing temperatures (-12°C) but do not overwinter consistently — particularly in areas of low snowfall and extended temperatures

Site suitability

• Grows best on well-drained loamy and clayey soils
• Does not do well on poorly drained soils and droughty, sandy and gravelly soils
• Has a pH range of 6.0 to 7.5
• Prefers fertile soils

Control options

• Mow and incorporate after flowering
• Chemical control

Sensitivity to herbicides

• Certain varieties tolerant of MCPA and metribuzin

Weed control

• Peas are generally not as effective as grass cover crops for weed suppression, particularly under warm conditions.
• Use narrow rows and appropriate agronomic practices to establish a vigorous crop canopy as soon as possible.
• Registered herbicides for Austrian winter peas include Basagran and Tropotox Plus.
• Registered broadleaf herbicides include Treflan, Tropotox Plus and Basagran as well as Poast for grasses.

Benefits and cautions

Nutrient management

• Fixes nitrogen — adding up to 100 lbs/ac

Pest management

• Can release an allelopathic compound as a root exudate (Beta alanine) which has been documented to cause reduced growth in some grass seedlings and germinating lettuce
• Peas are an attractive host crop for nematodes
• Peas often have high aphid populations, but can also provide cover for a number of beneficial insects, including predatory mites and lady beetles
• Bees are attracted to fields of flowering peas
• Can reduce incidence of wheat-disease — take-all

Organic matter

• Adds considerable biomass to soil — from the seed and stubble
• Crop residue readily breaks down
• Can be used as feed - either as forage or as dried seed supplement

Getting started

Establishment

• Seeding rates vary with seed size, 100 to 150 kg/ha
• Ensure good soil moisture and seed to soil contact
• Create fine seedbed with smooth surface to ensure uniform planting depth

Cost and availability

• Expensive seed and requires high seeding rates widely available