Adaptation of winter cereal species to shade and competition in a winter/spring cereal forage mixture

• Published in: Canadian journal of plant science 1996-04, Vol.76 (2), p.251-257
• Main Authors: Baron, V.S, De St Remy, E.A, Salmon, D.F, Dick, A.C
• Format: Article
• Language: English
• Subjects: adaptation; continuous cropping; crop mixtures; crop production; forage; gas exchange; Hordeum vulgare; leaves; measurement; plant morphology; respiration; Secale cereale; shade; shoots; spring and winter habit; triticale; Triticum aestivum; weight
• ISSN: 0008-4220; 1918-1833
• DOI: 10.4141/cjps96-045

Spring planted mixtures of spring and winter cereals maximize dry matter yield and provide fall pasture by regrowth of the winter cereal. However, delay of initial harvest may reduce the winter cereal component and therefore subsequent regrowth yield. Research was conducted at Lacombe, Alberta to investigate the effect of time of initial cut (stage), winter cereal species (species) and cropping system (monocrop and mixture) on winter cereal shoot weight, leaf carbon exchange efficiency and shoot morphology. These parameters may be related to adaptation of winter cereals to growth and survival in the mixture. Winter cereal plants were grown in pails embedded in monocrop plots of fall rye (Secale cereale L.), winter triticale (X Triticosecale Wittmack) and winter wheat (Triticum aestivum L.) and in binary mixtures with Leduc barley (Hordeum vulgare L.). The plants were removed when the barley reached the boot (B), heads emerged (H), H + 2, H + 4 and H + 6 wk stages. Shoot weight was generally smaller in the mixture than in the monocrop and wheat was reduced more than fall rye and triticale in the mixture compared to the monocrop. Dark respiration rate (r = −0.54) and carbon exchange (r = 0.36) under low light intensity were correlated (P