Soil disturbance changes arbuscular mycorrhizal fungi richness and composition in a fescue grassland in Alberta CanadaPublished: 01 October 2018 by Elsevier BV in Applied Soil Ecology
Native grasslands are endangered by non-native plant invasion worldwide, including foothills fescue grasslands in North America. Large populations of non-native plant species have established in these disturbed fescue grasslands, forming dense monocultures and spreading into undisturbed areas. Soil disturbance and plant invasion can alter the arbuscular mycorrhizal fungi (AMF) community, an important symbiotic partner of most land plants, which could negatively affect native plant reestablishment. The objective of this study was to assess whether AMF communities on a fescue grassland shifted in response to disturbances by landfill storage and gravel quarrying and with invasion of non-native plant species relative to undisturbed grassland. Soil and root-AMF samples were procured from disturbed and undisturbed areas at three sites. Plant canopy cover and species richness were assessed. Soils were analyzed for pH; electrical conductivity; total nitrogen, carbon and phosphorus; and available nutrients. For relative AMF taxa abundance assessment, NS31 and AMF specific primer AML2 were used to amplify a central fragment of the V3 and V4 region of the 18S rRNA gene. AMF were characterized using 454 pyrosequencing and multiplexed barcoded samples amplified from genomic DNA isolated from roots. There were 92 AMF, including 15 potentially novel taxa detected. AMF communities in disturbed and undisturbed sampling locations were distinct except for one site, and indicator AMF virtual taxa (VT) for undisturbed grassland and disturbed sites were identified. AMF richness was higher in undisturbed (72 VT) than disturbed (64 VT) sites and AMF richness was positively correlated with plant species richness, diversity and native plant cover, and negatively correlated with non-native plant cover. There were 43 AMF VT on undisturbed and disturbed sites, 62% with higher relative abundance on disturbed sites. Site disturbance shifted AMF communities relative to undisturbed native fescue grassland; thus restoration success with native plants might be highly dependent on reintroducing native AMF.
Plant community development following reclamation of oil sands mine sites in the boreal forest: a reviewPublished: 01 September 2018 by Canadian Science Publishing in Environmental Reviews
Understanding how reclamation practices influence plant community assembly and succession is an important step in developing realistic indicators and targets for reclamation of oil sands mine sites to upland forest ecosystems. We currently have a poor understanding of factors affecting plant community assembly and succession in reclaimed oil sands sites. Through synthesis of research completed over the last 24 years, we identify four key findings: 1) use of surface soil and forest floor material salvaged from mined areas increases plant species cover, richness and diversity relative to the use of various other cover soil materials (such as clay subsoil); 2) stockpiling of salvaged surface soils decreases the abundance of native plant propagules and delays early vegetation community development; 3) differences in plant community composition between reclaimed and adjacent mature forests remain two decades after placing cover soils; However, differences are smaller with use of forest floor - mineral mix than peat - mineral mix; and 4) plant community assembly is in progress but communities remain different to those found in natural undisturbed conditions. Our review identified critical knowledge gaps for further research to improve understanding of: 1) long term (60 to 100 years) plant community composition in reclaimed oil sands sites; 2) how residual forest patches near disturbed oil sands sites act as seed and propagule sources in newly reclaimed sites; 3) plant community assembly processes in reclamation sites; 4) the effect of micro-topographic heterogeneity on plant community development; and 5) how soil nutrient availability in different substrates influences plant community development over the long term. Ongoing support for selected existing studies and establishment of new studies focussing on plant community development through long term monitoring are highly recommended.
Eleven years of simulated deposition of nitrogen but not sulfur changed species composition and diversity in the herb st...Published: 01 March 2018 by Elsevier BV in Forest Ecology and Management
Transplanting Following Non-Native Plant Control in Rocky Mountain Foothills Fescue Grassland RestorationPublished: 28 February 2018 by University of Wisconsin Press in Ecological Restoration
Disturbed areas within national parks, resulting from historic and current land use activities, can harbor large and diverse populations of non-native plant species. These species must be controlled to prevent their spread and to restore native grassland. Research on alternative revegetation methods is urgently needed since seed based grassland restoration is often unsuccessful. The effectiveness of transplanting to restore foothills fescue grassland following implementation of non-native plant management was investigated at three disturbed sites in Waterton Lakes National Park, Alberta, Canada. Non-native plant abundance was reduced by cutting, glyphosate application, and steaming. Greenhouse grown seedlings of native fescue grassland species (13 forbs, five grasses, two shrubs) were outplanted into plots following management treatments, as three different sizes of container stock. The effects of prior non-native plant management and container size on transplant survival and growth were assessed over two growing seasons. Rhizomatous forbs and bunchgrasses with well-developed root systems had highest survival (> 50% over 14 months). Transplants with 10- to 15-cm rooting depth in cones and root trainers had significantly higher within-year survival than tray transplants with a shallow rooting depth. Transplant survival was improved by glyphosate application to control non-native plants prior to planting. Transplanting was effective for increasing native cover and species richness although high winter mortality reduced this effect. Key species for fescue grassland function were introduced at all sites and persisted for two growing seasons.
Microbial Activities and Gross Nitrogen Transformation Unaffected by Ten-Year Nitrogen and Sulfur AdditionPublished: 01 January 2018 by Soil Science Society of America in Soil Science Society of America Journal
Oil sands mining in northern Alberta, Canada, emits large amounts of NOx and SO2 to the atmosphere, which will eventually return to the surrounding forest ecosystems. This study was conducted to determine changes in microbial and enzyme activities, and gross nitrogen transformation rates in a boreal forest soil in response to 10 yr (2006–2015) of elevated levels of nitrogen (N) and sulfur (S) addition. The experiment had a two (0 vs. 30 kg N h–1 yr–1, as NH4NO3) × two (0 vs. 30 kg S ha–1 yr–1, as Na2SO4) factorial design with three blocks. A laboratory incubation experiment was conducted using forest floor and the mineral soil (0–15 cm). Ten years of elevated N and S additions did not affect soil chemical (pH, total C, total N and available N concentrations) and microbiological properties (microbial biomass C and N, soil respiration rate, and enzyme activities related to C and N cycling) and gross N transformation rates. Gross N mineralization (0.54–0.62 and 36–49 mg N kg–1 d–1 for mineral soil and forest floor, respectively) and gross NH4+ immobilization (0.39–0.57 and 10–19 mg N kg–1 d–1, respectively) rates were tightly coupled in both soil layers. Gross NO3- immobilization rates (20–32 mg N kg–1 d–1) were significantly greater than gross nitrification rates (9–20 mg N kg–1 d–1) in the forest floor. Our results suggest that the studied boreal forest soil was resilient or resistant to 10 yr of N and S addition and the studied soils were still N limited. Given the current N and S emission and deposition rates in northern Alberta, the risk for N and S deposition to significantly affect gross N transformation rates is low for the studied forest ecosystem. Copyright © 2018. . Copyright © by the Soil Science Society of America, Inc.
Mycorrhization affects root distribution of Lotus corniculatus and Calamagrostis epigeios in a nutrient poor heterogeneo...Published: 01 December 2017 by Elsevier BV in Rhizosphere
Soil pollutants such as hydrocarbons can induce toxic effects in plants and associated arbuscular mycorrhizal fungi (AMF). This study was conducted to evaluate if the legume Lotus corniculatus and the grass Elymus trachycaulus and arbuscular mycorrhizal fungi could grow in two oil sands processing by-products after bitumen extraction from the oil sands in northern Alberta, Canada. Substrate treatments were coarse tailings sand (CTS), a mix of dry mature fine tailings (MFT) with CTS (1:1) and Pleistocene sandy soil (hydrocarbon free); microbial treatments were without AMF, with AMF and AMF plus soil bacteria isolated from oil sands reclamation sites. Plant biomass, root morphology, leaf water content, shoot tissue phosphorus content and mycorrhizal colonization were evaluated. Both plant species had reduced growth in CTS and tailings mix relative to sandy soil. AMF frequency and intensity in roots of E. trachycaulus was not influenced by soil hydrocarbons; however, it decreased significantly over time in roots of L. corniculatus without bacteria in CTS. Mycorrhizal inoculation alone did not significantly improve plant growth in CTS and tailings mix; however, inoculation with mycorrhizae plus bacteria led to a significantly positive response of both plant species in CTS. Thus, combined inoculation with selected mycorrhizae and bacteria led to synergistic effects. Such combinations may be used in future to improve plant growth in reclamation of CTS and tailings mix.
Heterogeneous soil conditions influence fungal alkaline phosphatase activity in roots of Lotus corniculatusPublished: 01 August 2017 by Elsevier BV in Applied Soil Ecology
QuestionWhat are the effects of cutting, glyphosate application and steam application on abundance and diversity of non-native grasses and forbs and non-target native grasses and forbs in restoration of a complex disturbed fescue grassland?LocationWaterton Lakes National Park, Alberta, Canada.MethodsCutting, glyphosate application and steam application treatments were implemented at three disturbed sites in an incomplete block design with a control. Plant communities were evaluated for four growing seasons, one before and three after management treatment implementation.ResultsGlyphosate reduced non-native grass cover for three growing seasons following application and non-native forbs for one growing season. Glyphosate led to significant increases in non-native forb cover, more than double pre-existing values 2 and 3 yr after application. Native species abundance and diversity were more negatively impacted by glyphosate on sites with higher abundance and diversity prior to management treatments. Low frequency cutting over 2 yr did not consistently control non-native species, steam reduced non-native grass cover at the most heavily invaded site.ConclusionsSite-specific conditions must be considered to develop effective control methods for non-native species. No treatment effectively re-established native grassland communities. Glyphosate application reduced non-native grasses, but not non-native forbs. When native forbs were abundant prior to management, glyphosate reduced them. Steam may have potential and should be further investigated. This is one of only a few studies to investigate methods to manage multiple non-native species occurring with native species, rather than management of a single undesirable species, and is the first to assess steam as a management option for native grasslands.
Effects of Boreal Well Site Reclamation Practices on Long-Term Planted Spruce and Deciduous Tree RegenerationPublished: 08 June 2017 by MDPI in Forests
Well site development associated with oil sands exploration is common in boreal mixedwood forests of northern Alberta, Canada, and necessitates reforestation to accommodate other land uses. Little is known about the impact of soil and debris handling strategies during well site construction on long-term forest regeneration. This study addresses the impact of soil disturbance intensity, debris treatment, soil storage, and planting on the reforestation of 33 well sites reclaimed prior to 2006. Data on the survival and growth of planted white spruce (Picea glauca (Moench) Voss) and the regeneration density of deciduous trees, including trembling aspen (Populus tremuloides Michx), are presented from 2014 to 2015. The survival of planted spruce increased from 81% to 88% at well sites with a high relative to low soil disturbance. The total tree densities were lower in most treatments (≤2.69 stems m−2) than those in clear cuts (5.17 stems m−2), with the exception of root salvage areas where clear cuts had greater balsam poplar (Populus balsamifera L.) densities (2.05 stems m−2 vs. <0.71 stems m−2 on all other treatments). Aspen densities were up to five times greater at well sites with low disturbance when compared to those with high disturbance, and this was further aided by shallow mulch at low disturbance sites. Spruce growth did not respond to well site treatments. Aspen growth (diameter and height) remained similar between well site disturbance regimes; aspen exposed to high disturbance underperformed relative to low disturbance well sites and clear cut controls. With high disturbance, progressive soil piling led to increases in the density of aspen and birch (Betula papyrifera Marshall). Few long-term changes in soil were found due to well site development, with a greater soil pH in high disturbance sites compared to low disturbance sites. Overall, these results indicate that the nature of well site construction, including the extent of soil removal, soil piling, and debris treatment, may collectively alter forest re-establishment, with associated implications for forest management.
Availability of native plant materials for grassland restoration is limited. Even when available in sufficient quantities for ecological restoration projects, seed germination and establishment in relatively arid environments is often low. Poor revegetation results in soil erosion, invasion by non-native plant species and reduced aesthetics. Therefore, development and use of native plants bred for traits favourable for restoration should be considered. This study addressed whether native cultivar seed, commercially selected for advantageous growth characteristics, could improve native grass species reestablishment relative to wild collected seed. Cultivar and wild seed types of four cool season native grass species were investigated at three foothills fescue grassland reclamation sites: Bromus carinatus (mountain brome), Elymus trachycaulus (slender wheatgrass), Festuca idahoensis (Idaho fescue) and Koeleria macrantha (June grass). Seeding and transplanting were conducted and germination, emergence, density, height and health were determined from 2011 to 2013. No significant differences were detected between cultivar and wild seed types except laboratory germination, which was greater in the Elymus trachycaulus cultivar and in the wild collected Koeleria macrantha. Bromus carinatus performed poorly as a seedling from either seed type. Consistent trends in cultivar and wild seed performance, that reflected seed germination, were found for each species although results were not significant due to high variability. Results show that for these common grass species, seed type may not influence initial establishment. Differences among species were significant and varied with response measured, suggesting species characteristics are a key factor affecting native grass reestablishment. Species specific responses to seed type highlight the importance of making seed source decisions on a species basis.
Early colonization of root associated fungal communities on reclamation substrates at a diamond mine in the Canadian Sub...Published: 01 February 2017 by Elsevier BV in Applied Soil Ecology
Mulch amendment facilitates early revegetation development on an abandoned field In northern mixed grass prairies of Nor...Published: 01 December 2016 by Elsevier BV in Ecological Engineering
Coarse woody debris effects on greenhouse gas emission rates depend on cover soil type in oil sands reclamationPublished: 01 April 2016 by Elsevier BV in Applied Soil Ecology
Highlights•Soil respiration and CH4 uptake rates were greater in FMM than in PMM.•Coarse woody debris increased soil respiration and CH4 uptake rates in FMM.•Soil respiration rates were positively related to MBC, MBN and soil temperature.•CH4 uptake rates were negatively related to soil water content.•Global warming potential of GHG effluxes was greater in FMM and near CWD. AbstractPeat mineral soil mix (PMM) and forest floor mineral soil mix (FMM) are cover soils commonly used for land reclamation, while coarse woody debris (CWD) can be added to create structural diversity and provide an additional source of organic matter. However, the effect of cover soil type and CWD on emission rates of greenhouse gases, such as carbon dioxide (CO2) methane (CH4) and nitrous oxide (N2O) in reclaimed oil sands soils has not been studied. Soil respiration, CH4 uptake and N2O emission rates were studied in a factorial experiment consisting of 2 cover soils (FMM vs PMM) × 2 sampling distances from the CWD (near vs away from CWD). Greenhouse gas emission rates were measured in July, August, and September 2012 and 2013 using static chambers. Soil respiration rates were greater in FMM than in PMM regardless of the distance from CWD at each sampling time (p < 0.05). Rates ranged from 461 to 1148 and 293 to 677 mg CO2 m−2 h−1 for FMM and PMM, respectively, in 2012, and from 355 to 1318 and 235 to 700 mg CO2 m−2 h−1, respectively, in 2013. The CWD increased soil respiration by 22–33% in FMM but not in PMM. Soil respiration rates were positively related to microbial biomass carbon (p = 0.004) and nitrogen (p < 0.001). Soil respiration rates decreased from July to September in 2012 and 2013, and were positively related to soil temperature (p < 0.01) but not with soil water content measured at 5 cm depth. Methane uptake rates were greater in FMM (0.026–0.037) than in PMM (0.015–0.028 mg CH4 m−2 h−1). The CWD increased CH4 uptake rates only in July and August 2012 in FMM, and were negatively related to soil water content (p < 0.001) but not to soil temperature. Nitrous oxide emission rates (0.001–0.016 mg N2O m−2 h−1) were not affected by either cover soil type or CWD. Global warming potential of CO2, CH4 and N2O effluxes was greater in FMM than in PMM and near CWD than away from CWD, especially in FMM. Our study demonstrates that applying CWD for oil sands reclamation increases organic matter decomposition (increased CO2 evolution), driven by the effect on microbial populations. Results from this study provide support to findings in earlier studies that CWD application benefits vegetation establishment through enhancing soil processes in reclaimed oil sands lands.
Nitrogen transformation rates are affected by cover soil type but not coarse woody debris application in reclaimed oil s...Published: 22 February 2016 by Wiley in Restoration Ecology
Forest floor mineral soil mix (FMM) and peat mineral soil mix (PMM) are cover soils commonly used for reclamation of open-pit oil sands mining disturbed land in northern Alberta, Canada; coarse woody debris (CWD) is another source of organic matter for land reclamation. We investigated net nitrogen (N) transformation rates in FMM and PMM cover soils near and away from CWD 4–6 years after oil sands reclamation. Monthly net nitrification and N mineralization rates varied over time; however, mean rates across the incubation periods and microbial biomass were greater (p < 0.05) in FMM than in PMM. Net N mineralization rates were positively related to soil temperature (p < 0.001) and microbial biomass carbon (p = 0.045). Net N transformation rates and inorganic N concentrations were not affected by CWD; however, the greater 15N isotope ratio of ammonium near CWD than away from CWD indicates that CWD application increased both gross N mineralization/nitrification (causing N isotope fractionation) and gross N immobilization (no isotopic fractionation). Microbial biomass was greater near CWD than away from CWD, indicating the greater potential for N immobilization near CWD. We conclude that (1) CWD application affected soil microbial properties and would create spatial variability and diverse microsites and (2) cover soil type and CWD application had differential effects on net N transformation rates. Applying FMM with CWD for oil sands reclamation is recommended to increase N availability and microsites.
Coarse Woody Debris Increases Microbial Community Functional Diversity but not Enzyme Activities in Reclaimed Oil Sands ...Published: 30 November 2015 by Public Library of Science (PLoS) in PLOS ONE
Forest floor mineral soil mix (FMM) and peat mineral soil mix (PMM) are cover soils commonly used for upland reclamation post open-pit oil sands mining in northern Alberta, Canada. Coarse woody debris (CWD) can be used to regulate soil temperature and water content, to increase organic matter content, and to create microsites for the establishment of microorganisms and vegetation in upland reclamation. We studied the effects of CWD on soil microbial community level physiological profile (CLPP) and soil enzyme activities in FMM and PMM in a reclaimed landscape in the oil sands. This experiment was conducted with a 2 (FMM vs PMM) × 2 (near CWD vs away from CWD) factorial design with 6 replications. The study plots were established with Populus tremuloides (trembling aspen) CWD placed on each plot between November 2007 and February 2008. Soil samples were collected within 5 cm from CWD and more than 100 cm away from CWD in July, August and September 2013 and 2014. Microbial biomass was greater (p<0.05) in FMM than in PMM, in July, and August 2013 and July 2014, and greater (p<0.05) near CWD than away from CWD in FMM in July and August samplings. Soil microbial CLPP differed between FMM and PMM (p<0.01) according to a principal component analysis and CWD changed microbial CLPP in FMM (p<0.05) but not in PMM. Coarse woody debris increased microbial community functional diversity (average well color development in Biolog Ecoplates) in both cover soils (p<0.05) in August and September 2014. Carbon degrading soil enzyme activities were greater in FMM than in PMM (p<0.05) regardless of distance from CWD but were not affected by CWD. Greater microbial biomass and enzyme activities in FMM than in PMM will increase organic matter decomposition and nutrient cycling, improving plant growth. Enhanced microbial community functional diversity by CWD application in upland reclamation has implications for accelerating upland reclamation after oil sands mining.
Coarse woody debris extract decreases nitrogen availability in two reclaimed oil sands soils in CanadaPublished: 01 November 2015 by Elsevier BV in Ecological Engineering
Fine root dynamics in lodgepole pine and white spruce stands along productivity gradients in reclaimed oil sands sitesPublished: 02 October 2015 by Wiley in Ecology and Evolution
Open‐pit mining activities in the oil sands region of Alberta, Canada, create disturbed lands that, by law, must be reclaimed to a land capability equivalent to that existed before the disturbance. Re‐establishment of forest cover will be affected by the production and turnover rate of fine roots. However, the relationship between fine root dynamics and tree growth has not been studied in reclaimed oil sands sites. Fine root properties (root length density, mean surface area, total root biomass, and rates of root production, turnover, and decomposition) were assessed from May to October 2011 and 2012 using sequential coring and ingrowth core methods in lodgepole pine (Pinus contorta Dougl.) and white spruce (Picea glauca (Moench.) Voss) stands. The pine and spruce stands were planted on peat mineral soil mix placed over tailings sand and overburden substrates, respectively, in reclaimed oil sands sites in Alberta. We selected stands that form a productivity gradient (low, medium, and high productivities) of each tree species based on differences in tree height and diameter at breast height (DBH) increments. In lodgepole pine stands, fine root length density and fine root production, and turnover rates were in the order of high > medium > low productivity sites and were positively correlated with tree height and DBH and negatively correlated with soil salinity (P < 0.05). In white spruce stands, fine root surface area was the only parameter that increased along the productivity gradient and was negatively correlated with soil compaction. In conclusion, fine root dynamics along the stand productivity gradients were closely linked to stand productivity and were affected by limiting soil properties related to the specific substrate used for reconstructing the reclaimed soil. Understanding the impact of soil properties on fine root dynamics and overall stand productivity will help improve land reclamation outcomes.
Use of drilling waste generated from the oil and gas industry for land reclamation has potential to be a practical and economical means to improve soil fertility and to decrease landfills. A four month greenhouse experiment with common barley (Hordeum vulgare L.) on three different textured soils was conducted to determine soil and plant response to incorporated or sprayed potassium silicate drilling fluid (PSDF). Two PSDF types (used once, used twice) were applied at six rates (10, 20, 30, 40, 60, 120m(3)ha(-1)) as twelve PSDF amendments plus a control (non PSDF). Effects of PSDF amendment on plant properties were significant, and varied through physiological growth stages. Barley emergence and below ground biomass were greater with used once than used twice PSDF at the same application rate in clay loam soil. Used twice PSDF at highest rates significantly increased barley above ground biomass relative to the control in loam and sand soil. All PSDF treatments significantly increased available potassium relative to the control in all three soils. Soil electrical conductivity and sodium adsorption ratio increased with PSDF addition, but not to levels detrimental to barley. Soil quality rated fair to poor with PSDF amendments in clay loam, and reduced plant performance at the highest rate, suggesting a threshold beyond which conditions are compromised with PSDF utilization. PSDF application method did not significantly affect plant and soil responses. This initial greenhouse research demonstrates that PSDF has potential as a soil amendment for reclamation, with consideration of soil properties and plant species tolerances to determine PSDF types and rates to be used.
Naturalization is a relatively new management strategy for green areas within the urban environment. The approach undertaken in this research was to stop mowing and then plant with native species. The information available for decision makers regarding naturalization is very limited. The urban planner based on previous experiences is recommended to establish native species to the region. Native species have specific adaptations that allow them to withstand and survive in their endemic habitat. By limiting human intervention and reintroducing native species an area is eventually naturalized, meaning no further management of the area is needed to become an assemblage of the naturally occurring landscape. The current study assesses how successfully these native plant species establish in an urban setting using naturalization as a management approach. A comparison between soil tillage and no tillage combined with compost and topsoil amendments being tested to identify the most suitable species for urban naturalization and the best management practices to enhance this practice. Naturalization is a strategy that presents a great opportunity for urban centers to integrate native species into the landscape. If done properly, a successful naturalization strategy can significantly improve city management costs, promote preservation of local species, restore environmental services and encourage more members of these communities to embrace naturalization as a desirable strategy to follow.
Linkage between root systems of three pioneer plant species and soil nitrogen during early reclamation of a mine site in...Published: 09 March 2015 by Wiley in Restoration Ecology
In 2005, a 7‐ha artificial watershed (Chicken Creek) was built on a post mined landscape in Lusatia, Germany from sandy substrates of Pleistocene origin, commonly used in reclamation. The watershed was developed to investigate the initial phase of soil and ecosystem development under natural conditions. At this early stage, mineral nitrogen in young sandy soils is primarily limited and nitrogen fixing legumes become key components of natural succession. Local abundant pioneering legumes Lotus corniculatus and Trifolium arvense and one pioneer grass species Calamagrostis epigeios were investigated 5 years after watershed construction. In this study, we investigated the influence of spatial root and nodule distribution of these species on soil nitrogen accumulation. Soil, including roots, was sampled from field monoliths covered with the aforementioned plant species. Root systems of both legumes were mainly restricted to the upper 20 cm of soil, whereas roots of C. epigeios also developed strongly at greater depths. A positive relationship was found, with higher plant densities associated with higher root densities which were associated with higher nodule densities for legumes and which were all associated with significantly higher soil nitrogen content relative to non‐vegetated areas. This research provides rare information on the role root systems of pioneer legumes play in soil nitrogen input in the early stage of soil and ecosystem development during revegetation by natural succession.
Potassium silicate drilling fluids (PSDF) are a waste product of the oil and gas industry with potential for use in land reclamation. Few studies have examined the influence of PSDF on abundance and composition of soil bacteria and fungi. Soils from three representative locations for PSDF application in Alberta, Canada, with clay loam, loam and sand textures were studied with applications of unused, used once and used twice PSDF. For all three soils, applying ≥40 m3/ha of used PSDF significantly affected the existing soil microbial flora. No microbiota was detected in unused PSDF without soil. Adding used PSDF to soil significantly increased total fungal and aerobic bacterial colony forming units in dilution plate counts, and anaerobic denitrifying bacteria numbers in serial growth experiments. Used PSDF altered bacterial and fungal colony forming unit ratios of all three soils.
Germination sensitivities to water potential among co-existing C 3 and C 4 grasses of cool semi-arid prairie grasslandsPublished: 09 January 2015 by Wiley in Plant Biology
An untested theory states that C4 grass seeds could germinate under lower water potentials (Ψ) than C3 grass seeds. We used hydrotime modelling to study seed water relations of C4 and C3 Canadian prairie grasses to address Ψ divergent sensitivities and germination strategies along a risk‐spreading continuum of responses to limited water. C4 grasses were Bouteloua gracilis, Calamovilfa longifolia and Schizachyrium scoparium; C3 grasses were Bromus carinatus, Elymus trachycaulus, Festuca hallii and Koeleria macrantha. Hydrotime parameters were obtained after incubation of non‐dormant seeds under different Ψ PEG 6000 solutions. A t‐test between C3 and C4 grasses did not find statistical differences in population mean base Ψ (Ψb(50)). We found idiosyncratic responses of C4 grasses along the risk‐spreading continuum. B. gracilis showed a risk‐taker strategy of a species able to quickly germinate in a dry soil due to its low Ψb(50) and hydrotime (θH). The high Ψb(50) of S. scoparium indicates it follows the risk‐averse strategy so it can only germinate in wet soils. C. longifolia showed an intermediate strategy: the lowest Ψb(50) yet the highest θH. K. macrantha, a C3 grass which thrives in dry habitats, had the highest Ψb(50), suggesting a risk‐averse strategy for a C3 species. Other C3 species showed intermediate germination patterns in response to Ψ relative to C4 species. Our results indicate that grasses display germination sensitivities to Ψ across the risk‐spreading continuum of responses. Thus seed water relations may be poor predictors to explain differential recruitment and distribution of C3 and C4 grasses in the Canadian prairies.
Organic capping type affected nitrogen availability and associated enzyme activities in reconstructed oil sands soils in...Published: 01 December 2014 by Elsevier BV in Ecological Engineering
Predicting Grassland Recovery with a State and Transition Model in a Natural Area, Central Alberta, CanadaPublished: 01 October 2014 by Natural Areas Journal in Natural Areas Journal
Potassium silicate drilling fluid (PSDF) is a relatively new type of drilling waste generated by the oil and gas industry. PSDF effects on soil, vegetation, and ground water must be determined before its land disposal and use in reclamation can be regulated. A laboratory column leachate study was conducted to quantify the response of select soil and leachate properties to PSDF at various depths in soil column profiles. A spent PSDF was applied to two soils (sand and loam textures) at four rates (20, 40, 60, 120 m3 ha−1) with two application methods (incorporated, sprayed). Changes to soil and leachate properties were at values that would not be detrimental to most plant species when PSDF was applied at ≤60 m3 ha−1. Applying PSDF at 120 m3 ha−1 had significant effects on soil properties and leachate quality. Hydraulic conductivity and field capacity were significantly reduced, and soil available potassium and sulfate concentrations, pH, and salinity increased with PSDF. Incorporated PSDF in the upper 10 cm of soil accelerated PSDF element transport through soil columns to leachate and increased organic carbon and salinity in leachate. PSDF application rate significantly reduced soil field capacity, available nitrogen, and increased salinity at the highest rates in loam soil, suggesting a threshold beyond which conditions will not be suitable for land spraying PSDF. This research demonstrates that PSDF has potential to improve soil short term water availability, macronutrient potassium and sulfur for disposal on cultivated and uncultivated lands. This potential should be field tested.
Germination photoinhibition is not a recognized cause of revegetation failure; yet prolonged sunlight exposure can inhibit germination of several grass species. This research addressed susceptibility to photoinhibition of selected native grass species used to restore Canadian prairies, and reclamation treatments to alter environmental conditions in order to release seeds from photoinhibition. Under laboratory conditions effects of photoinhibition were tested on the ability of seeds to germinate at low water potential and effects of daily alternating temperatures and nitrates to break photoinhibition. Whether surficial mulch can release seeds from photoinhibition was assessed in a field experiment. Germination photoinhibition was evident in Festuca hallii and Koeleria macrantha seeds even under very low irradiances. The prolonged exposure to light decreased germination rates and ability of seeds to germinate at low water potentials. Daily fluctuating temperatures released a fraction of Bromus carinatus and Elymus trachycaulus seeds from photoinhibition yet did not improve F. hallii or K. macrantha germinability. Nitrates failed to break seed photoinhibition in all species tested. In the field experiment, mulched F. hallii seeds (covered with an erosion control blanket) showed a tenfold increase in germination percentages relative to seeds exposed to direct sunlight, indicating the facilitative effects of mulching on attenuation of the light environment. We conclude that germination photoinhibition as a cause of emergence failures in land reclamation where seed is broadcast or shallow seeded should be recognized and germination photoinhibition included in the decision making process to select revegetation seeding techniques.
Establishment of Restoration Trajectories for Upland Tundra Communities on Diamond Mine Wastes in the Canadian ArcticPublished: 22 May 2014 by Wiley in Restoration Ecology
Mining in the arctic amplifies restoration challenges due to inherent environmental conditions by removing soil, vegetation, and the propagule bank, adding coarse textured wastes with low water holding capacity and nutrients, and introducing salt and metal contamination. Short‐term reclamation focuses on rebuilding soil and providing rapid native plant cover for erosion control, supporting longer term reestablishment of ecological processes for sustainable tundra communities that provide essential wildlife habitat. This study evaluated methods to restore soil and plant communities 5 years after implementation of treatments at a diamond mine in the Canadian arctic. Five substrates including mine waste materials (processed kimberlite, glacial till, gravel, and mixes), four amendments (inorganic fertilizer, salvaged soil, sewage sludge, and water treatment sludge), five native species seed mixes and natural recovery were investigated. Soil and plant response were assessed annually. Soil chemistry was ameliorated with time. Chromium, cobalt, and nickel concentrations in processed kimberlite remained high and potentially toxic to plants. Adding fine textured materials such as glacial till to mine wastes improved nutrient and water retention, which in turn enhanced revegetation. Sewage and inorganic fertilizer increased available nitrogen and phosphorus, plant density and cover. Soil amendment increased species richness. Seeding was essential to establish a vegetation cover. After 5 years, seed mix composition and diversity had no effect on plant community development; soil and plant community properties among treatments changed considerably, providing evidence that restoration in the arctic is dynamic yet slow and success cannot be determined in the short term.
Mature fine tailings (MFT) are a by-product of oil sands mining that must be reclaimed through capping or use as a reclamation substrate. Some chemical and physical properties of MFT make it inhospitable for plant growth, such as high concentrations of sodium, sulfate, chloride, and hydrocarbons. A greenhouse study assessed whether substrates of various mixes of dry MFT, overburden sand, and peat mineral soil mix (PMM) and caps of forest floor organic material (LFH) and PMM would support the emergence and growth of three native grass species commonly used in land reclamation. Select vegetation properties were monitored for 16 wk in the greenhouse; select chemical and physical substrate properties were determined in the laboratory. was more tolerant of dry MFT than and . Mean aboveground and belowground biomass were more than twice as high on substrates with <60% MFT than on 100% MFT. Aboveground biomass was two to four times greater with capping than without and 30% greater on LFH than PMM caps. Cover and density followed similar trends. Belowground biomass on capped substrates was at least double that on uncapped substrates. Aboveground biomass was almost doubled with the use of fertilizer. High concentrations of hydrocarbons and exchangeable ions were associated with reduced plant growth and health. Results from this study show that capping, amendments, and fertilizer may improve the reclamation potential of dry MFT.
Compost is a readily available source of organic matter and nutrients and is produced large scale in many jurisdictions. Novel advancements in composting include addition of construction waste, such as drywall, to address its disposal while potentially improving compost quality for use in land reclamation. Varying compositions (15-30% by weight) of coarse and ground waste drywall were added to manure and biosolids during composting. Six composts were applied at four rates (0, 50, 100, 200 Mg ha(-1)) to three reclamation soils (agricultural, urban clean fill, oil sands tailings). Response to composts was assessed in the greenhouse with three plant species (Hordeum vulgare L. (barley), Agropyron trachycaulum (Link) Malte (slender wheat grass) and Festuca saximontana Rydb. (rocky mountain fescue). Drywall added to biosolids or manure during composting had no detrimental effects on vegetation; any negative effects of compost occurred with and without drywall. In agricultural soil and clean fill, biosolids composts with 15% coarse and 18% ground drywall improved native grass response, particularly biomass, relative to biosolids compost without drywall. Drywall manure composts reduced native grass response relative to manure compost without drywall. Only low quality tailings sand was improved by 30% coarse drywall. Compost rate significantly affected above and below ground biomass in agricultural soil and reduced performance of native species at highest rates, suggesting a threshold beyond which conditions will not be suitable for reclamation. Grinding drywall did not significantly improve plant performance and use of coarse drywall would eliminate the need for specialized equipment and resources. This initial research demonstrates that drywall composts are appropriate soil amendments for establishment of native and non native plant species on reclamation sites with consideration of substrate properties and plant species tolerances to dictate which additional feed stocks should be used.
In situ measurement of snowmelt infiltration under various topsoil cap thicknesses on a reclaimed sitePublished: 01 September 2013 by Agricultural Institute of Canada in Canadian Journal of Soil Science
Christensen, A. F., He, H., Dyck, M. F., Turner, L., Chanasyk, D. S., Naeth, M. A. and Nichol, C. 2013. In situ measurement of snowmelt infiltration under various topsoil cap thicknesses on a reclaimed site. Can. J. Soil Sci. 93: 497–510. Understanding the soil and climatic conditions affecting the partitioning of snowmelt to runoff and infiltration during spring snow ablation is a requisite for water resources management and environmental risk assessment in cold semi-arid regions. Soil freezing and thawing processes, snowmelt runoff or infiltration into seasonally frozen soils have been documented for natural, agricultural or forested systems but rarely studied in severely disturbed systems such as reclaimed lands. The objective of this study was to quantify the snowmelt infiltration/runoff on phosphogypsum (PG) tailings piles capped with varying thicknesses of topsoil (0.15, 0.3, and 0.46 m) at a phosphate fertilizer production facility in Alberta. There are currently no environmental regulations specifying topsoil capping thickness or characteristics for these types of tailings piles. Generally, the function of the topsoil cap is to facilitate plant growth and minimize the amount of drainage into the underlying PG. Experimental plots were established in 2006 to better understand the vegetation and water dynamics in this reconstructed soil. In 2011, time domain reflectometry (TDR) probes and temperature sensors were installed at various depths for continuous, simultaneous, and automated measurement of composite dielectric permittivity (ɛeff) and soil temperature, respectively. An on-site meteorological station was used to record routine weather data. Liquid water and ice content were calculated with TDR-measured effective permittivity (ɛeff) and a composite dielectric mixing model. Spatial and temporal change of total water content (ice and liquid) revealed that snowmelt infiltration into the topsoil cap increased with increasing topsoil depth and net soil water flux from the topsoil cap into the PG material was positive during the snowmelt period in the spring of 2011. Given the objective of the capping soil is to reduce drainage of water into the PG material it is recognized that a capping soil with a higher water-holding capacity could reduce the amount of meteoric water entering the tailings.
Erosion control blankets, organic amendments and site variability influenced the initial plant community at a limestone ...Published: 31 July 2013 by Copernicus GmbH in Biogeosciences
Season of seeding and soil amendment with manure mix, wood shavings and erosion control blankets were evaluated over two growing seasons to determine their effect on soil properties and native grass establishment at a Canadian limestone quarry and lime processing plant. A season (fall, spring) of soil amending and seeding did not significantly affect revegetation or soil properties. Site characteristics such as slope, aspect, initial soil nutrients and surrounding plant communities influenced early plant community development and overall effects of soil treatments. Erosion control blankets resulted in the highest seeded plant cover and the lowest non-seeded plant cover despite not significantly changing soil chemical properties. Total nitrogen and carbon significantly increased establishment of seeded grasses and non-seeded species. Increased nitrogen and carbon in the constructed soils were best achieved through addition of manure. Wood shavings did not favour establishment of vegetation and resulted in similar, and in some cases less, vegetation than the controls. Assisted revegetation increased plant cover from < 6 to 50% and reduced cover of non-seeded species. Amendments that modified both chemical and physical soil conditions were best to increase vegetation establishment in the harsh conditions of the quarry.
Mining disturbs large forested areas around the world, including boreal forests after oil sands mining in Canada. Industrial companies are expected to reclaim degraded land to ecosystems with equivalent land capability. This research showed the value of woody debris for reclamation of dramatically disturbed landscapes with a forest ecosystem end land use. Adding woody debris during reclamation can facilitate recovery of flora, soil nutrient cycling and water and nutrient holding capacity. Combined with forest floor material, woody debris can provide native plant propagules that would be otherwise commercially unavailable. Sites with and without woody debris on forest floor material containing identifiable litter (L), fragmented and fermented litter (F), and humus (H) (LFH), and peat mineral soil mix (peat) cover soils were studied. Within 2 years, woody debris decreased bare ground and created microsites which were positively associated with greater vegetation cover and woody plant density. Woody debris treatments had lower soil available nitrate and soil under woody debris had a lower temperature range and higher soil volumetric water content than control treatments without woody debris. Woody debris did not affect first year microbial biomass carbon or mycorrhizae, but both were greater on LFH than peat cover soil. LFH was associated with lower bare ground and greater vegetation cover, species richness, and soil phosphorus and potassium than peat cover soil, which had greater soil sulfate.
Environmental sustainability of post mined limestone quarries often requires reclamation to a diverse woody plant community. Woody species diversity may be severely limited if only nursery stock is relied on for propagation material; thus other sources must be evaluated. To address woody species establishment and survival from different propagule sources at a limestone quarry in western Canada, native trees (4) and shrubs (3) were seeded and transplanted into amended substrates (wood shavings, clean fill, unamended control) in two seasons (spring, fall). Plant sources were nursery stock, local forest wildlings, seeds and forest soil (LFH mineral soil mix). Plant emergence, survival, height, health and browsing were evaluated over four years. Survival was greater with fall transplanted seedlings than with spring transplanted. Survival was greater for Picea glauca, Pseudotsuga menziesii and Populus tremuloides from nursery than local source stock. Seedlings from seeds and LFH did not survive for any of the species. Growth and survival were affected by bighorn sheep. Amendments did not improve plant establishment. Diversity of the woody plant community was increased at the quarry in spite of the severe conditions.
Promising results in central Alberta with rough fescue (Festuca hallii) seeding following disturbancePublished: 01 March 2013 by University of Wisconsin Press in Native Plants Journal
Plains rough fescue ( Festuca hallii (Vasey) Piper [Poaceae]), once dominant in rough fescue grasslands of central Canada and the northern US, recovers poorly if disturbed by cattle grazing or oil and gas production soil handling techniques. This long-lived bunchgrass requires 3 to 5 y to become established, during which time it may be exposed to competition from faster-growing species. Our first research objective was to assess the recovery of F. hallii by comparing a monoculture seeding to a mixed seeding of native grass (Poaceae) species including F. hallii , Koeleria macrantha (Ledeb.) Schult., Elymus trachycaulus (Link) Gould ex Shinners ssp. subsecundus (Link) Á. Löve & D. Löve, Pascopyrum smithii (Rydb.) Á. Löve, Nassella viridula (Trin.) Barkworth, Hesperostipa comata (Trin. & Rupr.) Barkworth, and Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths. Our second objective was to evaluate plant community development of both seeding mixes. We established seeding experiments on 3 field sites in central Alberta, Canada. When seeded as a monoculture, the F. hallii plant community that resulted included native species re-established from the seedbank or seed rain, such as Helictotrichon hookeri (Scribn.) Henr. (Poaceae). In the native species seed mix, wheatgrasses ( E. trachycaulus ssp. subsecundus and P. smithii ) dominated in the first 3 y with low F. hallii cover. We recommend seeding F. hallii with few or no aggressive species, such as wheatgrasses, in the seed mix.
Establishment of a native bunch grass and an invasive perennial on disturbed land using straw-amended soilPublished: 01 January 2013 by Elsevier BV in Journal of Environmental Management
Native grasslands around the word face increased threats from non-native species. Fescue prairie in North America, in good rangeland condition, is dominated by the perennial bunch grass, Festuca hallii, whereas disturbances are often colonized by Poa pratensis, an introduced perennial rhizomatous grass which is competitive in nitrogen rich soils. F. hallii thrives in typical low nitrogen grassland soils and recovers poorly once disturbed. Disturbance to soil caused by well site construction may decrease organic carbon and potassium, and increase nitrogen, phosphorus, pH and electrical conductivity, creating conditions conducive to invasion by P. pratensis. This research tested the hypothesis that F. hallii would tolerate nitrogen depleted soil, through addition of carbon as a straw amendment to newly reclaimed well sites, better than P. pratensis. Our second hypothesis was that F. hallii is negatively affected by disturbed soil and P. pratensis is not. We treated three sites with three straw amendment rates, seeded monocultures of F. hallii and P. pratensis, and monitored establishment over three years. F. hallii biomass, root biomass, leaf length and cover increased in response to straw treatments, whereas P. pratensis showed little response. F. hallii was positively affected by prior-year soil water, and current-year ammonium and potassium. P. pratensis was positively affected by current-year soil water, potassium and nitrate. P. pratensis responded positively to higher pH and electrical conductivity found in disturbed soil and F. hallii responded poorly. The positive relationship of P. pratensis to pH above 7 could explain why it can invade reclaimed disturbed grassland; whereas the negative reaction of F. hallii might explain its failure to recover. We concluded the addition of straw as a soil amendment is a possible solution to poor establishment of F. hallii.
Krümmelbein, J., Bens, O., Raab, T. and Naeth, M. A. 2012. A history of lignite coal mining and reclamation practices in Lusatia, eastern Germany. Can. J. Soil Sci. 92: 53–66. Germany is the world's leading lignite coal producer. The region surrounding the towns of Cottbus and Senftenberg in Lusatia, Eastern Germany, is one of the largest mining areas in Germany, and has economically been strongly dependent on lignite mining and lignite processing industries since the middle of the 19th century. We introduce the area, give a brief historical overview of lignite mining techniques and concentrate on post-mining recultivation (reclamation) to agricultural and forestry dominated landscapes. An overview of the physical and chemical limitations for reclamation of the Tertiary and Quaternary substrates due to their natural composition and the technical processes of mine site construction is provided. We introduce some recultivation practices and end with a display of land uses before and after mining and an outlook on the future use of the reclaimed landscape. This review serves as a defined perspective on long-term coal mine reclamation from which to address global similarities and contrasts. Krümmelbein, J., Bens, O., Raab, T. and Naeth, M. A. 2012. A history of lignite coal mining and reclamation practices in Lusatia, eastern Germany. Can. J. Soil Sci. 92: 53–66. Germany is the world's leading lignite coal producer. The region surrounding the towns of Cottbus and Senftenberg in Lusatia, Eastern Germany, is one of the largest mining areas in Germany, and has economically been strongly dependent on lignite mining and lignite processing industries since the middle of the 19th century. We introduce the area, give a brief historical overview of lignite mining techniques and concentrate on post-mining recultivation (reclamation) to agricultural and forestry dominated landscapes. An overview of the physical and chemical limitations for reclamation of the Tertiary and Quaternary substrates due to their natural composition and the technical processes of mine site construction is provided. We introduce some recultivation practices and end with a display of land uses before and after mining and an outlook on the future use of the reclaimed landscape. This review serves as a defined perspective on long-term coal mine reclamation from which to address global similarities and contrasts.
Naeth, M. A., Archibald, H. A., Nemirsky, C. L., Leskiw, L. A., Brierley, J. A., Bock, M. D., VandenBygaart, A. J. and Chanasyk, D. S. 2012. Proposed classification for human modified soils in Canada: Anthroposolic order. Can. J. Soil Sci. 92: 7–18. With increasing anthropogenic activity, the areal extent of disturbed soils is becoming larger and disturbances more intense. Regulatory frameworks must incorporate reclamation criteria for these disturbed soils, requiring consistent descriptions and interpretations. Many human altered soils cannot be classified using the Canadian System of Soil Classification (CSSC), thus an Anthroposolic Order is proposed. Anthroposols are azonal soils, highly modified or constructed by human activity, with one or more natural horizons removed, removed and replaced, added to, or significantly modified. Defining features are severe disruption of soil forming factors and introduction of potentially new pedogenic trajectories. Disturbed layers are anthropic in origin and contain materials significantly modified physically and/or chemically by human activities. Three great groups are defined by presence of anthropogenic artefacts and organic carbon content. Six subgroups are based on a cover soil layer with higher organic carbon content than the profile below it, on depth of disturbance, on drainage characteristics and water regime at the site. Some new phases and modifiers, in addition to traditional ones used in the CSSC, are based on chemical and physical properties and origins of anthropogenic artefacts. The proposed classification has been successfully applied to reclaimed profiles and is ready for widespread field testing.
Evaluation of substrate and amendment materials for soil reclamation at a diamond mine in the Northwest Territories, Can...Published: 01 January 2012 by Agricultural Institute of Canada in Canadian Journal of Soil Science
Drozdowski, B. L., Naeth, M. A. and Wilkinson, S. R. 2012. Evaluation of substrate and amendment materials for soil reclamation at a diamond mine in the Northwest Territories, Canada. Can. J. Soil Sci. 92: 77–88. Mine waste materials with potential for use in soil construction at a diamond mine in the Northwest Territories were evaluated to address physical and chemical limitations for plant establishment, growth and development. Substrates were glacial till, gravel, processed kimberlite, and 50:50 and 25:75 mixes of processed kimberlite and till. Amendments were salvaged topsoil, sewage sludge, inorganic fertilizer and sludge from a water treatment facility. Reclamation soils constructed with these materials were adequate for revegetation. Mixes of processed kimberlite and glacial till enhanced soil structure and diluted adverse concentrations of elements. The original gravel pad, alone or amended, was a suitable substrate for plants. Addition of organic amendments topsoil and sludge, to any substrate, increased organic matter, nutrients and surface water retention. Of amendments evaluated, salvaged topsoil provided the most consistent increase in plant density among substrates. Inorganic fertilizer applied to gravel or till provided results similar to those with topsoil. Sludge had potential to amend mixes of processed kimberlite and till, although results were variable. Sewage was a good source of organic matter, increasing soil water content and macro nutrients. Vegetation response was poor in sewage-amended treatments likely due to combined effects of high copper, molybdenum, phosphorus, selenium, sulphate and zinc.
Influence of biosolids and fertilizer amendments on element concentrations and revegetation of copper mine tailingsPublished: 01 January 2012 by Agricultural Institute of Canada in Canadian Journal of Soil Science
Gardner, W. C., Naeth, M. A., Broersma, K., Chanasyk, D. S. and Jobson, A. M. 2012. Influence of biosolids and fertilizer amendments on element concentrations and revegetation of copper mine tailings. Can. J. Soil Sci. 92: 89–102. A 3-yr field study on copper mine tailings in British Columbia determined the effects of fertilizer and biosolids on element concentrations in tailings and vegetation and on plant biomass. Biosolids applied at 50, 100, 150, 200 and 250 Mg ha−1 (dry weight) increased total carbon, iron, magnesium, nickel, nitrogen, phosphorus, sulphur and zinc and available ammonium, iron, manganese, nitrate, phosphorus and zinc in tailings. With highest applications on silt loam tailings, total zinc (214 mg kg−1) exceeded Canadian Council of Ministers of the Environment guidelines for agricultural soils. Total chromium and copper exceeded these guidelines but not due to biosolids, being high in controls (chromium 38, 8; copper 647, 1291 mg kg−1; silt loam and sandy sites, respectively). Plant tissue calcium, phosphorus, magnesium, manganese, nitrogen and zinc increased with increasing biosolids. Plant tissue calcium (20 g kg−1) and molybdenum (5 mg kg−1) exceeded National Research Council maximums for beef cattle. Total molybdenum in unamended silt loam (35 mg kg−1) and sandy tailings (18 mg kg−1) and vegetation on silt loam (112 mg kg−1) were high. Biosolids had variable effects on tailings molybdenum and decreased total plant tissue molybdenum. Fertilizer and control treatments had limited plant growth. Managed biosolids use in reclamation can ameliorate sites and facilitate vegetation establishment, with low environmental risk.