Plant growth in four overburden types used in the reclamation of extracted oil sands.

Abstract

Two shallow mineral overburden, a deep mineral overburden and a peat overburden from northern Alberta were examined. Jack pine Pinus banksiana and slender wheatgrass Agropyron trachycaulum were grown in 30-cm-deep cores in which the overburdens were placed in either 5- or 15-cm-deep layers over oil sand tailings. Cores containing a mixture of sand, peat and deep overburden were also used. Growth of slender wheatgrass was best in the peat and very poor in the deep overburden. Jack pine also grew very poorly in the deep overburden but reasonably well in the other 3 overburdens. There was extensive root development of both species in the sand layer beneath all overburden types. Increasing the depth of peat from 5 to 15 cm resulted in a decrease in the growth of both plants; increasing the depth of the mineral overburdens had favorable effects. The amount of available P was much higher in sand under the 5-cm layers than sand under the 15-cm layers. Iron and Mn uptake was suppressed with the thick layer of peat. Mixing 15 cm of peat with deep overburden and sand did not affect growth of slender wheatgrass but reduced shoot production of jack pine.-from Authorsjack pine Pinus banksiana slender wheatgrass Agropyron trachycaulum Dept. of Biology, Univ. of Calgary, Alberta T2N 1N4, Canada.