Soil Microbiology in Land Reclamation. Volume II – Mycorrhizae

Dennis Parkinson
Resource Date:
Page Length

There are three reports in Volume II: Parkinson, D., 1984. Greenhouse pot studies dealing with amendation of oil sands tailings: Effects of peat, sewage sludge and fertilizer on plant growth, mycorrhizae and microbial activity. 90 pp. Abstract: Carex and feather moss peats from northern Alberta were used as growth media for jack pine and slender wheatgrass and their microbiological properties assessed. Differences between the two peats were minimal. Following this assessment, mixtures of the two peats were used to amend oil sand tailings (55% peat, V/V) and either mineral fertilizers or sewage sludge were added at different rates. Slender wheatgrass and jack pine were grown in the greenhouse in the various growth media, and plant growth, microbial activity and mycorrhizal development were measured. Growth of both species was poor without the addition of either fertilizer or sewage. Fertilization up to the equivalent of 112:49:72 kg N:P:K ha-1 substantially increased shoot and root growth of slender wheatgrass. Shoot growth of jack pine reached a maximum at the 28:12:18 kg ha-1 rate, and pine roots weights were depressed when more than 56:24:36 kg ha-1 were applied. Maximum shoot growth of slender wheatgrass and jack pine occurred with the equivalent of 46 and 23 mT ha-1 sewage respectively. The addition of 92 mT ha-1 strongly depressed the growth of jack pine while slender wheatgrass was unaffected. In the absence of peat, slender wheatgrass was much more sensitive to sewage. VA mycorrhizal inoculum in the peat was sparse and high levels of fertilizer or the lowest level of sewage completely inhibited VA mycorrhizal infection. Ectomycorrhizal inoculum was abundant but infections were nil when more than 56:24:36 kg N:P:K ha-1 was applied and very strongly reduced when 23 mT ha-1 or more of sewage was applied. In the presence of slender wheatgrass, fertilizer increased microbial biomass but had no effect when no plants were present, i.e. fertilizer did not affect the decomposition of peat. Microbial activity (C02 efflux) was unaffected by the addition of fertilizer but decomposition of grass litter was reduced by high rates of fertilizer. When sewage was added to the growing medium, microbial activity and microbial biomass were increased and the decomposition potential was decreased. The presence of the fibrous rooted slender wheatgrass consistently inhibited the decay of grass litter as compared to unplanted systems.

Danielson, R.M., C. Griffiths and D. Parkinson, 1984. Reinstatement of biological activity in severely disturbed soils: Ectomycorrhizae in amended oil sand tailings and subalpine coal mine spoil and in undisturbed jack pine and spruce stands. 97 pp. Abstract: The vesicular-arbuscular mycorrhizal (VAM) development of slender wheatgrass on extracted oil sands tailings and a subalpine coal mine spoil amended with either fertilizer, peat, or sewage sludge was examined over a 4 yr period. During the first growing season on the oil sands spoil mycorrhizae were limited to plants on the peat-amended spoil. While VAM infection was not detected in plants on the fertilized plots until the end of the second growing season, plants on the sewage- amended plots were not mycorrhizal until after the 4th yr. VAM infection in plants on the subalpine mine spoil was detected at 2 wk only in the peat-amended spoil. Although sewage initially suppressed the rate of mycorrhizal development, plants did develop VA mycorrhizae by the 10 wk sampling time. The mycorrhizal status of plants on the amended subalpine mine spoil did not change significantly between the 2nd and 4th year. Glomus aggregatum and Glomus mosseae were the most common VA fungi in the amended spoils. In the oil sands tailings, VA fungal spores were detected only in the control and peat-amended plots. While there was no amendment effect on spore densities of G. mosseae in the subalpine coal spoil, spore numbers of G. aggregaturn were significantly reduced in the sewage-treated spoil. The successful reestablishment of VA mycorrhizal in mine spoils will depend in part on the effects of soil amendments on VA fungal species occurrence and inoculum production.

Zak, J.C., C. Griffiths and D. Parkinson, 1984. Reinstatement of biological activity in severely disturbed soils: Vesicular-arbuscular mycorrhizal development of slender wheatgrass on amended oil sands tailings and subalpine coal mine spoil. 58 pp. Abstract: The mycorrhizal status of jack pine and bearberry grown in oil sand tailings treated with various amendments (peat, mineral fertilizer, liquid sewage sludge) and of white spruce and willow grown in subalpine coal mine spoil using the same amendments was monitored for 4 years. In addition, ectomycorrhizae associated with jack pine and white spruce on undisturbed and disturbed field sites were studied and compared to those found in the amendment study. Application of sewage sludge increased the rate of ectomycorrhizal development of jack pine, slowed the mycorrhizal development of white spruce and bearberry, and apparently did not affect the mycorrhizae of willow. Peat introduced inoculum of several species of ectomycorrhizal symbionts and when ectomycorrhizal inoculum in the spoil was low, its application resulted in more rapid mycorrhizal development. Mineral fertilizer had little effect on mycorrhizal development. The most common ectomycorrhizal fungus was the E-strain which dominated white spruce in all treatments and jack pine in the peat. At the end of 4 years the E-strain fungi were being replaced on white spruce by Amphinema byssoides and was apparently replacing Thelephora terrestris on jack pine in all treatments except the peat amendment. Agarics constituted a minor portion of the ectomycorrhizal fungi whereas at least four Ascomycetes and three Aphyllophoreales were present. Once established, the specific symbioses were stable for at least several years. More than 50 species of ectomycorrhizal fungi were identified from fruit bodies on a mature jack pine field site. On this site Cenococcum geophilum, Tricholoma flavovirens and Lactarius spp. formed a large proportion of the ectomycorrhizae. Species fruiting in an adjacent cutline were largely different from those occurring in the undisturbed mature stand. Amphinema byssoides was a dominant symbiont of both mature spruce trees and of spruce seedlings regenerating on roadcuts.