Mineral Soil Cover Research Articles

Reduced nitrogen losses from drained temperate agricultural peatland after mineral soil coverage

Draining peatlands for agriculture induces peat decomposition, subsidence, and carbon (C) and nitrogen (N) losses, thereby contributing to soil degradation and climate change. To sustain the agricultural productivity of these organic soils, coverage with mineral soil material has increasingly been used. To evaluate the effect of this practice on the N flows within the plant–soil system, we conducted a 15N tracer experiment on a drained peatland that was managed as an intensive meadow. This peatland was divided into two parts, either without (reference “Ref”) or with ~ 40 cm mineral soil cover (coverage “Cov”). We applied 15NH415NO3 on field plots to follow the fate of 15N in plant–soil system over 11 months. In addition, N mineralization was determined by laboratory incubation. The field experiment showed that Cov lost less 15N (p < 0.05) than Ref, even though plant 15N uptake was similar at both sites. The lower net N loss from the Cov site was accompanied by higher soil 15N retention. The laboratory incubation revealed a ~ 3 times lower N mineralization at Cov than at Ref, whereas the N release per unit soil N was around two times higher at Cov than at Ref, suggesting a faster SOM turnover rate at Cov. Overall, the mineral soil cover increased the retention of fertilizer-N in the soil, thus reducing the system N losses. Our result indicates that agricultural production on drained peatland is less harmful to the environment with mineral soil coverage than using drained peatland directly.

Reduced Nitrous Oxide Emissions From Drained Temperate Agricultural Peatland After Coverage With Mineral Soil

Peatlands drained for agriculture emit large amounts of nitrous oxide (N2O) and thereby contribute to global warming. In order to counteract soil subsidence and sustain agricultural productivity, mineral soil coverage of drained organic soil is an increasingly used practice. This management option may also influence soil-borne N2O emissions. Understanding the effect of mineral soil coverage on N2O emissions from agricultural peatland is necessary to implement peatland management strategies which not only sustain agricultural productivity but also reduce N2O emissions. In this study, we aimed to quantify the N2O emissions from an agriculturally managed peatland in Switzerland and to evaluate the effect of mineral soil coverage on these emissions. The study was conducted over two years on a grassland on drained nutrient-rich fen in the Swiss Rhine Valley which was divided into two parts, both with identical management. One site was not covered with mineral soil (reference “Ref”), and the other site had a ∼40 cm thick mineral soil cover (coverage “Cov”). The grassland was intensively managed, cut 5–6 times per year, and received c. 230 kg N ha−1 yr−1 of nitrogen fertilizer. N2O emissions were continuously monitored using an automatic time integrating chamber (ATIC) system. During the experimental period, site Ref released 20.5 ± 2.7 kg N ha−1 yr−1 N2O-N, whereas the N2O emission from site Cov was only 2.3 ± 0.4 kg N ha−1 yr−1. Peak N2O emissions were mostly detected following fertilizer application and lasted for 2–3 weeks before returning to the background N2O emissions. At both sites, N2O peaks related to fertilization events contributed more than half of the overall N2O emissions. However, not only the fertilization induced N2O peaks but also background N2O emissions were lower with mineral soil coverage. Our data suggest a strong and continued reduction in N2O emissions with mineral soil cover from the investigated organic soil. Mineral soil coverage, therefore, seems to be a promising N2O mitigation option for intensively used drained organic soils when a sustained use of the drained peatland for intensive agricultural production is foreseen, and potential rewetting and restoration of the peatland are not possible.

Long-term responses of ground beetles (Coleoptera: Carabidae) to clear-cutting and wildfire in lodgepole pine stands of western Alberta, Canada

Abstract We studied responses of carabid beetles (Coleoptera: Carabidae) to clear-cutting and wildfire in lodgepole pine forests in the foothills of Alberta, Canada during 2013–2014 and compared the results with those from a similar study conducted in the same area during 1989–1990. Assemblages from stands regenerating 12–53 years after harvest gradually recovered towards their presumed preharvest condition represented by old pyrogenic stands. Assemblage structure in postharvest stands of similar age had also largely converged with that in stands that had burned in 1957 and 1997. Composition of ground vegetation, mineral soil cover, and basal area of trees and shrubs were significantly correlated with carabid assemblage structure, suggesting that plant successional gradients and patterns in carabid assemblages are driven by similar factors. We found that no carabid species was strictly associated with old pyrogenic stands, although assemblages in pyrogenic stands were distinctive. We predict that composition of carabid assemblages in harvested stands will recover and roughly match the variable structure of assemblages remaining in old, never-cut pyrogenic stands, given sufficient time (≥ 50 years). Nonetheless, the carabid fauna of the eastern slopes of Alberta’s Rocky Mountains appears to be changing in response to factors other than forestry. Warming climate is an explanation consistent with the changes observed.

The complex of machines for low-cost artificial reforestation in the taiga zone

Problems of mechanization of artificial reforestation in the taiga zone are increasing the productivity of manual labour and reducing the costs of subsequent young stand treatment (early tending and early pre-commercial thinning). Petrozavodsk State University has developed the complex of machines and technologies capable to solve these problems. This complex includes: seeder, root-cutter, dynamic hole-maker and mechanical mounder. Seeder and root-cutter are intended for growing enlarged seedlings with an open root system in forest nurseries. Seeder provides mechanization of sowing seeds. Root-cutter is used for pruning the root systems of seedlings during cultivation. Dynamic hole-maker provides strip soil clearing, surface tillage and preparation of holes for manual planting of seedlings. The hole-maker is also capable to make soil scarification and sowing forest seeds. Mechanical mounder provides strip clearing in the forest plot and creation of humus mounds with mineral soil cover for manual planting of seedlings. Basic technological parameters of the complex of machines have been also substantiated at the Petrozavodsk State University.

Soil carbon loss from drained agricultural peatland after coverage with mineral soil

Drainage for agriculture has turned peatlands from a net sink to a net source of carbon (C). In order to reduce the environmental footprint of agricultural peatland drainage, and to counteract soil subsidence, mineral soil coverage is becoming an increasingly used practice in Switzerland. To explore the effect of mineral soil coverage on soil C loss and the source of CO2 from peatland drained for agriculture, we utilized the radiocarbon signature (F14C) of soil C and emitted CO2 in the field. The experiment, located in the Swiss Rhine Valley, was carried out on two adjacent drained organic soils, either without mineral soil cover (reference ‘Ref’), or covered with mineral soil (thickness ~ 40 cm) (coverage ‘Cov’) 13 years ago. Drainage already commenced 130 years ago and the site was managed as meadow since the 1970ies. Drainage induced 41–75 kg C m−2 loss, which is equivalent to annual C loss rates of 0.49–0.58 kg C m−2 yr−1 and 0.31–0.63 kg C m−2 yr−1 for Cov and Ref, respectively. Mineral soil coverage had no significant effect on the amount of heterotrophic respiration, however, at Cov, the radiocarbon signature of heterotrophic CO2 was significantly (p<0.01) younger than at Ref, indicating that mineral soil coverage moved the source of decomposition of soil organic carbon (SOC) from a higher share of old peat towards a higher share of relatively younger material. In summary, our study lends support to the hypothesis that mineral soil coverage might reduce the decomposition of old peat underneath, and may therefore be a promising peatland management technique for the future use of drained peatland for agriculture.

The mechanical mounder technological parameters justification

For intensive reforestation, machines should be used that will not only reduce the time and labour required for artificial reforestation, but also reduce the need for subsequent young stand treatment (early tending and early pre-commercial thinning). These machines include machines for creating the humus mounds with mineral soil cover - for example a domestic rotary tool ORM-1.5 or its foreign counterparts - a two-row mounder of the Bracke M24.a type and a three-row mounder of the Bracke M36.b type. Petrozavodsk State University (PetrSU) has developed the design of a new two-row forestry machine for creating humus mounds with mineral soil cover - the mechanical mounder MK-2 (RF patent No. 141061, IPC A01G 23/00). The paper discusses the methodology for calculating the main technological parameters of the MK-2 mechanical mounder machine: the mounder machine rotors angular velocity, the mounds and depressions parameters formed by the mounder rotors (height, depth and length); the gear ratio between the power take-off shaft of the tractor and the mounder rotors’ value. The calculations established that the main design parameter of mounder MK-2 – the rotor rotation speed – must be four times less than the forestry unit translational speed (tractor + mounder) to achieve a common step in the mounds preparation about 1.2 m. The developed machine further studies (the MK-2 mounder) are recommended in the following directions: the MK-2 mounder design parameters refinement based on the testing prototype results in the field; technology development for the MK-2 mounder rational use for reforestation.

Effects of clear-cutting and wildfires on succession of ground beetle (Coleoptera: Carabidae) assemblages on the east slopes of the Rocky Mountains

We studied how carabid beetle assemblages in lodgepole pine stands have responded after clear-cut harvest and wildfires on an actively managed landscape ~20 km south of Hinton, Alberta, Canada. The work builds on and expands a previous study (Niemela et al. 1993) conducted 23-24 years earlier in many of the same stands sampled in the current study. Carabid species assemblages are compared along a chronosequence of stands ranging in age from 12 to 53 years after clear-cutting. Recovery of carabid assemblages toward pre-harvest structure in regenerating stands, as reflected in the 2013-14 data, appears to have progressed more rapidly than in equivalently aged stands from the earlier study. In addition, carabid species assemblages differed significantly between clear-cut and burned stands of comparable age in 2013-14, with assemblages of burned stands being more similar to the pre-harvest structure than in clear-cut stands. Ground vegetation, mineral soil cover and basal area of trees and shrubs were significantly correlated with structure of carabid species assemblages in young and old regenerating stands, suggesting that environmental and plant successional gradients drive patterns in carabid assemblages. However, assemblage differences between older burned and clear-cut stands indicate that the type of disturbance influences long-term carabid recovery. Relationships between these findings and issues related to conservation of biodiversity and climate change are discussed.

Overstory Structure and Surface Cover Dynamics in the Decade Following the Hayman Fire, Colorado

The 2002 Hayman Fire burned with mixed-severity across a 400-ha dry conifer study site in Colorado, USA, where overstory tree and surface cover attributes had been recently measured on 20 0.1-ha permanent plots. We remeasured these plots repeatedly during the first post-fire decade to examine how the attributes changed through time and whether changes were influenced by fire severity. We found that most attributes were temporally dynamic and that fire severity shaped their dynamics. For example, low-severity plots experienced a modest reduction in live overstory density due to both immediate and delayed tree mortality, and no change in live overstory basal area through time; in contrast, high-severity plots experienced an immediate and total loss of live overstory density and basal area. Large snag density in low-severity plots did not vary temporally because snag recruitment balanced snag loss; however, in high-severity plots large snag density increased markedly immediately post-fire and then declined by about half by post-fire year ten as snags fell. Mineral soil cover increased modestly immediately post-fire in low-severity plots and substantially immediately post-fire in high-severity plots, but changed little in ensuing years for either severity class. By incorporating pre-fire and repeatedly-measured post-fire data for a range of severities, our study uniquely contributes to the current understanding of wildfire effects in dry conifer forests and should be of interest to managers, researchers, and others.

Areal variability of the mineral soil cover in a reclaimed soda waste dumping site

Abstract Areal variability of the mineral soil cover in a reclaimed soda waste dumping site. This paper provides an analysis of the areal variability of the thickness and selected physical and chemical properties of the mineral cover formed in the process of settling ponds reclamation at the former Krakow Soda Plant “Solvay”. The topsoil is intended to provide a substrate for plants, therefore, its quality is the main determinant of the development for herbaceous and woody vegetation. Areal variability of the topsoil parameters was determined by kriging. In the context of the envisaged direction of management of the settling ponds, the analysis showed that electrical conductivity, thickness of the soil cover and the sand fraction content have potentially the highest impact on the diversification of vegetation. Understanding the spatial variability of the soil cover parameters, that are essential for vegetation, may contribute to increasing the efficiency of biological reclamation and also to cost reduction. Precise selection of the areas unsuitable for plant growth makes it possible to improve soil parameters on limited areas similarly as in the precision agriculture.

Soil disturbance and early vegetation response to varying intensity of energy wood harvest

Forest biomass plays an important role in the production of renewable energy, particularly in northern Europe. During recent decades, tree stumps have also been increasingly used for energy production. The environmental impacts of stump removal on the functioning of forest ecosystems, for example on soil processes and biodiversity, are still inadequately understood. To investigate the separate impacts of tree stump and logging residue removal on soil and plant variables, we conducted a large-scale replicated experiment in clear-felled stands in three geographical areas. Four energy wood harvesting levels were combined with patch mounding (organic and mineral soil layer turned upside down) as a site preparation method. The harvesting treatments were: (1) no energy wood harvesting, (2) 70% logging residue removal, (3) 25 stumps per hectare left at site and 70% logging residue removal (maximum level in official recommendations), (4) complete stump and 100% logging residue removal. Soil disturbance in terms of mineral and organic soil cover increased with the increasing harvesting level, but complete stump removal did not increase the mineral soil cover more than partial stump removal (on average 95% removed). Despite the increase in soil disturbance, stump removal did not have an overall impact on plant species richness or vegetation composition in the second growing season after harvesting. However, an increasing trend in Betula spp. biomass with increasing harvesting intensity was seen in two of three study areas in four years. Our results underscored the high site-dependency of the effects of stump removal on ecological variables, thus the initial stand structure and vegetation type need to be considered when planning harvesting treatments.

Long-term effects of chaining treatments on vegetation structure in piñon–juniper woodlands of the Colorado Plateau

Over the last half-century a range of methods have been utilized to reduce trees and shrubs in order to reduce wildfire risk and promote herbaceous vegetation to support livestock and wildlife. We examined the long-term (20–40year) effects of past tree-reduction treatments on vegetation and ground cover in piñon–juniper woodlands, which is the third most extensive vegetation type in the continental United States. Tree-reduction treatments were conducted between 1963 and 1988 in Grand Staircase-Escalante National Monument, Utah by the US Bureau of Land Management and involved chaining followed by seeding to remove trees and often shrubs. Treatments were effective at increasing perennial grass cover and reducing tree cover over multiple decades. The increase in perennial grass cover was predominantly due to a nonnative species that was seeded, Agropyron cristatum (crested wheatgrass). Surface fuel loads were nearly twice as high in treated areas, likely changing fire behavior and increasing habitat complexity. Treated areas had higher bare mineral soil cover and lower biocrust cover, which may influence soil erosional processes. Interestingly, treated areas had significantly less Pinus edulis (piñon pine) recruitment compared to untreated areas, while there was no change in Juniperus osteosperma (Utah juniper) recruitment. These results indicate that treated areas may become more J. osteosperma dominated in the future due to increased establishment of J. osteosperma compared to P. edulis. Our results show that while treatments were effective at reducing tree cover and increasing herbaceous cover, there were long-term (40year) treatment effects on vegetation composition and ground cover that need to be taken under consideration when developing future management strategies.

Design of top covers supporting aerobic in situ stabilization of old landfills – An experimental simulation in lysimeters

Landfill aeration by means of low pressure air injection is a promising tool to reduce long term emissions from organic waste fractions through accelerated biological stabilization. Top covers that enhance methane oxidation could provide a simple and economic way to mitigate residual greenhouse gas emissions from in situ aerated landfills, and may replace off-gas extraction and treatment, particularly at smaller and older sites. In this respect the installation of a landfill cover system adjusted to the forced-aerated landfill body is of great significance. Investigations into large scale lysimeters (2×2×3m) under field conditions have been carried out using different top covers including compost materials and natural soils as a surrogate to gas extraction during active low pressure aeration. In the present study, the emission behaviour as well as the water balance performance of the lysimeters has been investigated, both prior to and during the first months of in situ aeration. Results reveal that mature sewage sludge compost (SSC) placed in one lysimeter exhibits in principle optimal ambient conditions for methanotrophic bacteria to enhance methane oxidation. Under laboratory conditions the mature compost mitigated CH4 loadings up to 300lCH4/m2d. In addition, the compost material provided high air permeability even at 100% water holding capacity (WHC). In contrast, the more cohesive, mineral soil cover was expected to cause a notably uniform distribution of the injected air within the waste layer. Laboratory results also revealed sufficient air permeability of the soil materials (TS-F and SS-Z) placed in lysimeter C. However, at higher compaction density SS-Z became impermeable at 100% WHC.Methane emissions from the reference lysimeter with the smaller substrate cover (12–52g CH4/m2d) were significantly higher than fluxes from the other lysimeters (0–19g CH4/m2d) during in situ aeration. Regarding water balance, lysimeters covered with compost and compost-sand mixture, showed the lowest leachate rate (18–26% of the precipitation) due to the high water holding capacity and more favourable plant growth conditions compared to the lysimeters with mineral, more cohesive, soil covers (27–45% of the precipitation).On the basis of these results, the authors suggest a layered top cover system using both compost material as well as mineral soil in order to support active low-pressure aeration. Conventional soil materials with lower permeability may be used on top of the landfill body for a more uniform aeration of the waste due to an increased resistance to vertical gas flow. A compost cover may be built on top of the soil cover underlain by a gas distribution layer to improve methane oxidation rates and minimise water infiltration. By planting vegetation with a high transpiration rate, the leachate amount emanating from the landfill could be further minimised. The suggested design may be particularly suitable in combination with intermittent in situ aeration, in the later stage of an aeration measure, or at very small sites and shallow deposits. The top cover system could further regulate water infiltration into the landfill and mitigate residual CH4 emissions, even beyond the time of active aeration.

Stocks and annual fluxes of organic carbon in the mineral soil cover of Estonia

Annual cycling of soil organic carbon (SOC) is the main driving force in the formation and functioning of soil cover. Therefore knowledge about it forms the scientific base for sustainable management and ecologically sound soil protection. Systematized parameters of the mean annual cycling of SOC by soils are analysed on the basis of the SOC stock densities (Mg ha -1 ) of 16 mineral soil groups. The SOC stocks according to soil groups for the soil cover (solum) as a whole and for their epipedon were calculated on the basis of mean SOC densities and their distribution area of soil types. In the Estonian mineral soil cover (32 351 km 2 ) a total of 323 ± 46 Tg (10 12 g) SOC is retained; 42% of this is sequestered into stabilized humus, 40% into unstable raw humus, and 18% into forest (grassland) floor and shallow peat layers. Of the total SOC stock, 75% is situated in biologically active epipedons and 25% in subsoil. The annual SOC inputs and outputs in natural soils, which were calculated on the basis of annual productivity, ranged from 0.2 to 3.6 Mg ha -1 yr -1 . The influence of land management peculiarities on the annual cycling and balance of SOC has been demonstrated by our own experimental research, as well as by data published in the literature. In this work the pedo-ecological causal regularities of SOC sequestration in mineral soil cover (SOC concentration, soil thickness, moisture regime, texture, carbonate content), and agro-technological possibilities for its regulation (crops and their rotation, level of subsidization and soil amelioration) are discussed.

Base cation nutrition for pine stands on lithic soils near Stockholm, Sweden

This study reports on base cation nutrition for pine stands growing on lithic soils, i.e. areas of exposed bedrock where very little or no mineral soil cover exists. Since there is little soil, the exchangeable pool of base cations must be very small and the aim was to determine the source of nutrients for the trees— from atmospheric input or from mineral weathering. The method used Sr isotopes as analogues for Ca. Because the 87 Sr 86 Sr distribution is specific for the source, Sr found in the biomass can be treated as a binary mixture of Sr from deposition and weathered bedrock minerals. The bedrock comprised gneisses or gneissic granite, but with varying chemistry. In four out of five sites, atmospheric deposition was found to be the dominant Sr (Ca) source. In one area, though, mineral weathering seems to be effectively the only source. The reason is assumed to be a different weathering rate. Only 3–16% of the Ca, Mg and K released by weathering and received by atmospheric deposition is used for biomass accumulation in the pine stands.

An application of &quot;7th Approximation&quot; to the classification of soils consisting of organic soil layer with thin mineral soil cover

An application of &quot;7th Approximation&quot; to the classification of soils consisting of organic soil layer with thin mineral soil cover