Sowing ratio and N fertilization affect yield and yield components of oat and pea in intercrops

Intercropping is of increasing interest in sustainable arable farming systems in temperate regions. This study was determined to assess the influence of sowing ratio and N fertilization on yield and yield components of oat (Avena sativa L.) and pea (Pisum sativum L.) in intercrops. A two-year field study was carried out on a fertile soil in eastern Austria with oat and pea sown in three substitutive sowing ratios and at different nitrogen levels. Oat was the dominant partner in the mixtures, strongly outcompeting pea. N fertilization increased the competitive ability of oat. Total grain yields were generally lower in intercrops than in pure stands; thus oat-pea intercrops failed to achieve a yield advantage. Sowing ratio and fertilization affected yield component parameters of oat and pea compared to the corresponding pure stands. Oat in intercrops used available environmental resources for increasing panicles plant−1 and grains panicle−1 whereas harvest index and grain weight of pea were negatively affected in the mixtures. In conclusion, oat-pea intercrops could no achieve higher grain yields than corresponding pure stands on a fertile soil.