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

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). 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. 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 (PO 25 ), 50 plants m −2 (PO 50 ), 75 plants m −2 (PO 75 ), 100 plants m −2 (PO 100 ), and 125 plants m −2 (PO 125 ). 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 (PO 125) 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 (PO 25 and PO 50 ) while for oat it was > 0.5 at higher densities (PO 75 , PO 100 and PO 125 ). 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. 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. • Pea-oat intercropping reduced pea and oat grain yields across various sites in conventional systems. • Increasing oat seeding rates increased total dry matter in pea-oat intercropping systems. • Increasing oat seeding rates consistently reduced lodging and the presence of weed did not impact lodging. • Land equivalent ratio for grains was only influenced by site-year and not seeding rates. • Net revenue gains for grain yields were higher in monocrops than intercropping systems.