Shoot-to-root ratios and root biomass of cool-season feed crops in a boreal Podzolic soil in Newfoundland

• Published in: Canadian Journal of Soil Science
• Main Authors: Kwabiah, A B, Spaner, D., Todd, A G
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2005
• Subjects: Soil Science; Newfoundland
• Online Access: http://dx.doi.org/10.4141/s02-032; http://www.nrcresearchpress.com/doi/pdf/10.4141/S02-032

Barley (Hordeum vulgare L.) and oat (Avena sativa L.) crops are grown as feed grains by Newfoundland (NL) dairy farmers. The cereals are either grown as monoculture or intercropped with field pea (Pisum sativum L.) with or without N fertilization. Two experiments were conducted in both 2000 and 2001 to evaluate the shoot-to-root (S:R) weight ratios and root biomass in these production systems. Experiment 1 involved monocultures of pea sown at 150 kg ha -1 , and barley and oat each sown at 170 kg ha -1 . For pea-barley and pea-oat intercrops, pea was sown at 150 kg ha -1 and each cereal component was sown at either 85 and 170 kg ha -1 . The seven treatments were referred to, respectively, as pea 150 , barley 170 , oat 170 , pea 150 -barley85, pea 150 -oat85, pea 150 -barley 170 , and pea 150 -oat 170 . Experiment 2 evaluated factorial combinations of two barley seeding rates of 107 kg ha -1 (low) and 157 kg ha -1 (high) and three N rates (0, 30 and 60 kg ha -1 ) applied at Zadok’s Growth Stage (ZGS 30). Root biomass was sampled from soil (30-cm depth) and determined at about the anthesis stage of oat and barley and the shoot biomass at maturity (ZGS 90). In exp.1, the S:R ratios of oat 170 and pea 150 -oat85and pea 150 -oat 170 ranged from 8.1 to 8.8 and were lower than barley 170 , pea 150 , pea 150 -barley85and pea 150 -barley 170 which ranged from 10.0 to 12.5. Barley 170 had the highest root biomass of 835 kg ha -1 followed by pea 150 -barley 170 (745 kg ha -1 ) and pea 150 -oat 170 (765 kg ha -1 ). Intercropping pea with cereals increased root biomas s by 31% for pea 150 -barley85and 48% for pea 150 -oat85compared to pea 150 . However, root biomass increased by 109% for pea 150 -barley 170 and 104% for pea 150 -oat 170 , indicating that the cereal component of the intercrops contributed more to the root biomass than the pea at the higher seeding rate of the cereal crop. In exp. 2, the 0 kg N ha -1 rate produced the lowest S:R ratios irrespective of the barley seeding rate. When N was applied, both the shoot ...