Biostimulants‐driven improvements in productivity, resource use efficiency and protein yield in pea–barley intercrops

Abstract Biostimulants promote plant growth, nutrient uptake, and drought tolerance, reducing reliance on synthetic fertilizers. Intercropping, involving multiple crop species on the same land, is a promising practice. In Denmark, pea ( Pisum sativum )–barley ( Hordeum vulgare ) intercrop (PBIC) is commonly used for grain and fodder production. Our study aimed to assess the effects of biostimulants on productivity, weed biomass, and protein content in PBIC versus sole crops. The grain yield was significantly different between pea sole, barley sole, and PBIC and highest in PBIC. Grain yield in PBIC was 21.42% and 85.93% more compared to barley sole and pea sole, respectively. PBIC recorded higher land equivalent ratio (LER) for grain yield. PBIC recorded highest aboveground dry biomass yield compared to sole crops. The PBIC recorded lower weed incidence than sole crops with reductions of 6.47% and 39.88% compared to the barley sole and pea sole, respectively. Among the biostimulant applications, compost tea yielded highest grain yield (56.95% more than control), and aboveground dry biomass (41.14% more than control) recorded lowest weed biomass (14.67% less than control) under the PBIC system. The highest LER was recorded in high fungal: bacterial compost (2.56) compared to control treatment without biostimulant (1.30). Our results showed higher protein content in barley intercropping grain and straw compared to the barley sole cropping system. Results showed that combining biostimulants in pea–barley intercropping enhances productivity for sustainable temperate farming.