A GROWTH CHAMBER STUDY OF COPPER NUTRITION OF CEREAL AND OILSEED CROPS IN ORGANIC SOIL
Copper nutrition of barley (Hordeum vulgare ’Conquest’), oats (Avena sativa ’Hudson’), wheat (Triticum aestivum ’Neepawa’), flax (Linum usitatissium ’Dufferin’) and canola (Brassica campestris ’Torch’) was studied on a severely Cu-deficient organic soil in a controlled environment growth chamber. The objective of the study was to facilitate identification of Cu-related growth disorders by establishing the critical levels for Cu in plant tissues of the crops listed above. Copper deficiency symptoms were exhibited by all crops when Cu was not applied. Copper concentrations in plant shoots were considered as low when they ranged from 3.0 to 4.9 μg Cu/g plant dry matter (pdm) for wheat, from 2.3 to 3.7 μg Cu/g pdm for barley, from 1.7 to 2.5 μg Cu/g pdm for oats, from 1.7 to 2.7 μg Cu/g pdm for canola and from 2.4 to 3.5 μg Cu/g for flax. The measurements were made at heading for the cereals, pod initiation for canola, and at flower initiation for flax. Concentrations below these ranges were considered deficient and above these ranges sufficient. The order of tolerance to Cu deficiency in the soil was canola>barley>oats>wheat>flax.Key words: Copper nutritional ranges, copper deficiency, mesisol