Pea-oats intercropping: Agronomy and the benefits of including oats as a companion crop

Context

Intercropping field pea (Pisum sativum L.) and oat (Avena sativa L.) can offer some benefits over monocropping to conventional grain and forage producers. Most studies have been conducted in organic systems with little information for conventional producers prompting a 2-year field study conducted at three Saskatchewan, Canada sites (SERF, IHARF, WCA).

Objective

This study aimed to assess pea-oat intercropping with oats sown at different seeding rates under conventional systems. Also, it investigates the profitability of pea-oat intercropping.

Methods

Treatments included monoculture pea (with and without weed control) and oats seeded at recommended rates; pea-oat intercrop with oats seeded at five seeding rates thus: Pea-oat (PO) intercrop with oats seeding rates targeted at 25 plant m⁻² (PO₂₅), 50 plants m⁻² (PO₅₀), 75 plants m⁻² (PO₇₅), 100 plants m⁻² (PO₁₀₀), and 125 plants m⁻² (PO₁₂₅).

Results

In pea-oat intercropping, increased oat seeding rates reduced pea plant height, pea dry matter and total dry matter compared with monoculture. The highest Pea-oat seeding rate (PO₁₂₅₎ decreased weeds by ∼ 50 % compared to pea monocrop at one site-year. Pea-oat intercropping, especially at high oat seeding rates reduced lodging. Oat grain yield showed a quadratic relationship with increasing seeding rate (r = 0.69; P < 0.020), and maximum oat grain yield was predicted at 163.7 plants m⁻². The Partial land equivalent ratios (PLER) for peas for grains and biomass was > 0.5 mostly at lower densities (PO₂₅ and PO₅₀) while for oat it was > 0.5 at higher densities (PO₇₅, PO₁₀₀ and PO₁₂₅). Land equivalent ratio (LER) differed with site-year with only 2 out of 5 site-years having LER > 1. Net revenue generated for grain yields were higher in Pm while intercropping reduced net revenue gains. Forage revenue did not differ between pea-oat intercropping seeding rates and was comparable to monocrops.

Conclusion and implications

Our findings suggest that pea-oat intercrop significantly reduced grain yields of peas and oats. Furthermore, with oat as a companion crop, intercropping can potentially be beneficial for weed control and lodging especially when oat is sown at higher seeding rates. This study provides an approach in which pea-oat intercropping could be a potential option for increased profitability in forage production systems.