Years Of Revegetation Research Articles

Acute toxicity, secondary metabolites, and antioxidant activity of Macaranga tanarius from post-coal mining and non-mining areas in East Kalimantan, Indonesia.

Coal plays a crucial role in Indonesia's foreign exchange and East Kalimantan's revenue sharing, yet its environmental impacts, including soil acidification, raises concerns. Reclamation measures involve revegetation with pioneer plants such as Macaranga sp., known for their medicinal properties. However, the pharmacological properties of these plants are influenced by secondary metabolites, which depend on soil parameters such as pH and nutrient levels. The aim of this study was to evaluate the acute toxicity, secondary metabolites, and antioxidant activities of Macaranga tanarius leaf extracts from post-coal mining area (MTPCMA) and non-mining area (MTNMA) alongside soil parameters. Acute toxicity of M. tanarius leaf extracts and soils were assessed using the brine shrimp lethality test (BSLT). Phytochemical screening was done using thin-layer chromatography (TLC), determining total phenolic (TPC) and flavonoid content (TFC). The DPPH radical scavenging assay was used to assess the antioxidant activity. A comparative analysis between MTPCMA and MTNMA was conducted using Student t-test. The data showed no significant difference in toxicity between MTPCMA and MTNMA leaf extracts (LC50 of 100-1000 µg/mL) (p=0.062), and soils from both areas were non-toxic (LC50 of >1000 µg/mL). Although heavy metal concentrations were higher in PCMA than in NMA soil (p<0.001), secondary metabolite compounds and TFC in both extracts were not significantly different (p=0.076). Both extracts contained flavonoids and polyphenols with antioxidant activity and terpenoids without antioxidant activities. The DPPH radical scavenging test suggested insignificant antioxidant activity between MTPCMA and MTNMA extracts (p=0.237). In conclusion, non-toxic soils in post-mining land and insignificant differences between MTPCMA and MTNMA extracts suggest good soil nutrient availability, highlighting the success of land recovery after 10 years of revegetation with M. tanarius.

Variation in soil characteristics of ex-coal mining areas in Sawahlunto, West Sumatra

Soil characteristics in ex-coal mining areas can be influenced by reclamation methods and the type and age of revegetation plants used. This reclamation can also significantly impact the soil chemistry of ex-mining areas. This research was conducted in ex-coal mining areas located in Parambahan, Batu Tanjung Village, Talawi District, Sawahlunto City, West Sumatra Province. The objective of this study is to analyze variations in the reclamation process and their effects on the chemical properties of soil in these areas. Observations were made in several plots, including land that had not been mined (natural forest), land revegetated with Acacia in the planting years of 1992, 2007, 2010 (without the use of topsoil), 2019, and 2021, and land revegetated with Sengon in 2022. In each plot, soil samples were collected at three depths: 0–5 cm, 5–10 cm, and 10–20 cm, to analyze soil chemical properties. These properties included pH, total nitrogen (N), available phosphorus (P), organic carbon (C), exchangeable base cations (K, Ca, Mg, and Na), cation exchange capacity, and exchangeable aluminum (Al). The results showed that variations in the years of revegetation and reclamation practices, such as the use of topsoil and plant types, significantly influenced soil chemical characteristics. The longer the period of revegetation, the better the improvement in the soil’s chemical properties, as indicated by changes in pH, total N, organic C, exchangeable K, Na, Ca, and Mg, cation exchange capacity, and a reduction in exchangeable Al. However, the availability of P, as indicated by available P, decreased after more than 30 years of revegetation.

Evolving characteristics of dissolved organic matter in soil profiles during 56 years of revegetation in Mu Us Sandy Land

Evolving characteristics of dissolved organic matter in soil profiles during 56 years of revegetation in Mu Us Sandy Land

First assessment of soil mesofauna, microbiota, and humic substances associations in a minesoil revegetated with four grasses in Brazil: An 18-year field study

Moving away from coal protects our environment and soil. However, coal use in 2022 exceeded all previous years, systematically generating minesoils. The reestablishment of vegetation and organisms in minesoils is jeopardized by excessive soil compaction, eventual acidity, and depletion of soil organic matter (SOM), fauna, and microbial communities. Therefore, monitoring the recovery of soil attributes and functions as influenced by revegetation species is crucial to understanding the processes and time of ecological restoration. We aimed to verify if 18 years of revegetation with perennial grasses (Hemarthria altissima, Paspalum notatum, Cynodon dactylon, Urochloa brizantha) transformed the minesoil a habitat for mites, springtails and other invertebrates as well as for soil microorganisms. Moreover, we investigated associations between these biological indicators with soil humic substances (HS) content. The minesoil is located in Candiota (Brazil), and was constructed in 2003, when revegetation with the grasses started. In 2021, soil samples (0.10 m depth) were collected to determine mites and springtails abundance, microbial respiration, carbon and metabolic quotient, soil, HS content, pH, bases, and aluminum saturation. In order to monitor the soil attributes recovery by the perennial grasses, the means of treatments were compared to the control using percentage differences (positive or negative), as the control was not part of the experimental design. The relationship between the biological variables and the soil variables was assessed using Spearman correlation, and the Canonical Correspondence Analysis was used to identify the performance of each grass in relation to the dataset. The associations observed confirm that the minesoil recovery process is still in its initial, mainly between soil biological functions with SOM humification. Positive associations occurred between mites and microbial respiration and accumulation of humin, especially with Urochloa brizantha revegetation.

Diversity of soil bacteria in alpine coal slag mountain grassland in different vegetation restoration years

PurposeThis study aimed to investigate changes in the bacterial diversity of the rhizosphere soil of slag mountains in different years of revegetation restoration.MethodsSeven soil samples were selected from different years of revegetation restoration in Qinghai, China. The bacterial community of each soil was analyzed via high-throughput sequencing using the Illumina MiSeq platform.ResultsStatistical analyses revealed that the diversity of the soil bacterial community was higher in the soil that was restored in 2017 than that in the soils restored from other years. 16S rRNA sequencing revealed that Proteobacteria and Actinobacteria were the dominant phyla. Sphingomonas was the dominant genus. Total nitrogen, available nitrogen, and total potassium influenced the horizontal community structure of the phylum, whereas total nitrogen, organic matter, and pH had a great influence on the horizontal community structure of the phylum. The richness and diversity of the bacterial community in the soils that underwent revegetation restoration were greater in the third year (2017) than in other years. In the seventh year of recovery, the richness and diversity of the bacterial community began to decline.ConclusionThe bacterial diversity of the soil in the coal mine slag mountain improved with the increase in vegetation restoration years.

Soil-ecological assessment of soils of abandoned lands of diggerent age in the southeast of West Siberia

The aim of the study. Assessment of the current state of agrophysical properties of soils, their soil-ecological status by calculating the soil-ecological index (SEI), as well as the study of vegetation cover of different-age abandoned lands in the forest-steppe zone of West Siberia within the Novosibirsk region. Location and time of the study. Novosibirsk Region, 2017–2022. Methods. Soils of the Predsalair drained plain (right-bank part of the Novosibirsk region) were studied. Twelve soil sections were studied on leached and podzolized chernozems, as well as on dark gray forest soils. Some of the studied soils had different degrees of washout prior to abandonment. The abandoned lands were young (2–4 years), middle (5–15 years) and old (more than 15 years). The age of these lands, i.e. the duration of their spontaneous self-revegetation, was determined based on satellite imagery data, information from local authorities and the methodology developed by the Institute of Soil Science and Agrochemistry of the Siberian Branch of the Russian Academy of Sciences. The study of vegetation cover was carried out according to standard methods. Soil samples were collected as a solid column; humus content, acidity, mobile forms of phosphorus and potassium, granulometric composition were determined. Samples were also taken to determine soil density (volumetric mass). For soil-ecological assessment the methodology of soil-ecological index (SEI) calculation was used. The methodology for SEI calculating combines soil fertility, climatic and geomorphologic soil factors. The SEI was calculated according to the methodology developed at the В.V. Dokuchaev Soil Institute by I.I. Karmanov. The following soil properties were also measured: granulometric composition by the sieve-pipette method, organic carbon (humus) by potassium dichromate digestion and pH by potentiometric method. Results. The article presents the agrophysical properties of soils, their soil-ecological assessment (SEI) and describes the vegetation cover of different-aged abandoned and revegetating lands in the forest-steppe zone of West Siberia within the Novosibirsk region. The vegetation revealed a smooth change in the species composition of plants, including a decrease in the proportion of annual and biennial species. The total aboveground production increased during the first 5–7 years of revegetation, afterwards reaching a plateau depending on the type of the formed community and conditions. Low values of SEI (38–41) were obtained for young and middle-aged abandoned lands in comparison with the virgin land (63), being caused by the lower content of nutrient elements and humus. In the long-term abandoned lands soils, that were not washed away, had an average SEI value of 55, while soils of old fallow lands previously washed away had an average 45. Conclusions. Based on the soil ecological condition in the studied abandoned lands, it can be concluded that the return of young and middle-aged lands to agricultural turnover makes sense as pastures and hayfields. Their use as arable land is inexpedient, mostly because of different degrees of washout due to their location on slopes of different length and steepness, as well as insufficient restoration of their properties. The old abandoned lands (in case of the absence of soil erosion) may well be returned to agricultural use, including as arable land.

Soil Quality Assessment of Different Land Use Types Based on TOPSIS Method in Hilly Sandy Area of Loess Plateau, Northern China.

In order to combat land desertification and to evaluate the soil quality of different cover land types, and thereby determine the best land use strategy for vegetation restoration, this research comprehensively analyzed the soil quality of different land use/cover types in the hilly sandy area of the Loess Plateau by using the Kruskal-Wallis test (K-W test) and principal component analysis (PCA) technique for order preference by the similarity to ideal solution (TOPSIS), and the potential ecological risk index (RI). The result indicated that the cropland abandonment over a period of time could improve the soil quality to a certain extent; however, the process of natural restoration was very slow compared with that of the planted mixed shrubs. The soil quality of all land use/cover types in the hilly sandy area of Youyu County clearly improved after 10-25 years of revegetation, but the degree of improvement varied greatly with the different planted species and their combinations. The low levels of soil organic matter, total nitrogen and available phosphorus were the major limiting factors affecting soil quality improvement under different land use/cover types, not metal toxicity. Pioneer species of H. rhamnoide, C. korshinskii and Pinus sylvestris var. mongolica, etc. are vital to vegetation restoration of the study area. Revegetation using these species is therefore recommended to combat future desertification in this area.

Physical restoration of a minesoil after 10.6 years of revegetation

Revegetation with different plant species has been a strategy to restore the minesoil profile quality in many countries. However, restoration studies about soils degraded by surface coal mining show that it is not easy a simple task to bring back degraded/mined soil to its near original configuration. Thus, our study monitored the physical restoration of a minesoil by 10.6 years over the same experimental unit used by Pauletto et al. (2016), when the minesoil was with 4.8 years of revegetation. The study was conducted in a coal mining area in Candiota city, Southern Brazil. The minesoil was constructed in early 2003, and the experiment was set up between September/October 2007. The species analyzed were Urochloa humidicola, Panicum maximum, and Urochloa brizantha. Natural soil under native vegetation was used as a reference. In April 2018, soil samples were collected in the 0.00–0.10 and 0.10–0.20 m layers, and the following soil attributes were determined: distribution of the water-stable aggregates in different size classes, tensile strength, soil organic carbon content, bulk density, total porosity, macroporosity, and microporosity. In addition, soil penetration resistance was measured in all experimental areas. The minesoil attributes improvement between 4.8 and 10.6 years occurred in depth, mainly with the cohesive aggregates breakdown, and macroporosity and soil organic carbon content increases. At 10.6 years of revegetation, all perennial grasses improved physical conditions up to 0.10 m depth of the minesoil, with good results than those observed in the natural soil. However, compaction persisted in the 0.10–0.20 m layer, as shown mainly by the higher tensile strength of the aggregates, soil penetration resistance, and bulk density.

Biological quality and organic matter dynamics in minesoil at 18 years reclamation with perennial grasses

Mining is one of the most destructive economic activities on natural ecosystems. There are around 750 ha impacted by open-pit coal mining in Candiota Mine, the largest in Brazil, with 1.2 billion tons subject to mining. In soils impacted by mining, litter decomposition, always linked to a more extended period of restoration and maintenance of the vegetation, presents positive correlations with the diversity of the edaphic fauna and the enzymatic activity of these areas, promoting improvements in the ecological functions of the new ecosystem. The objective of the present study was to analyze the impact of revegetation with different summer perennial grasses subjected to different mowing managements on the biological and chemical quality of soils after coal mining in an experimental area at the Candiota Mine. Analyzes were performed to identify edaphic organisms using modified Berlese-Tüllgren funnels and microbiological analyzes to quantify Microbial Biomass Carbon (MBC), Microbial Respiration (MR), and urease enzymatic activity. The different fractions of Soil Organic Matter (fulvic, humic acids, and humin) were also quantified to understand the degree of humification in the area. All results were compared in mean tests by Tuckey's test (p < 0.05) and by Principal Component Analysis. After 18 years of revegetation and 11.6 years of mowing management in the area, there was an improvement in MBC and MR compared to the Control, evidencing the positive effect of the perennial grasses used in the experimental area. However, mowing management cannot yet be considered the most promising management for improving edaphic conditions.

Evaluating Spatiotemporal Patterns of Post-Eruption Vegetation Recovery at Unzen Volcano, Japan, from Landsat Time Series

Quantifying vegetation responses after natural disasters helps clarify complex relationships between vegetation and surface processes such as soil erosion. The heterogenous post-disaster landscape offers a naturally stratified environment for this study. Existing research tends to be frequently monitored but small-scale or sporadically monitored but large-scale. The availability of high-quality and free satellite imagery bridges this gap by offering continuous, longer-term observations at the landscape scale. Here we take advantage of a dense Landsat time series to investigate landscape-scale vegetation response rates and factors at Unzen volcano, Japan. We do this by first investigating differences between two popular vegetation indices—The Normalized Difference Vegetation Index (NDVI) and the Normalized Burn Ratio (NBR), when applied to recovery studies. We then apply pixel-wise regressions to quantify spatio-temporal vegetation response and regression tree analyses to investigate drivers of recovery. Our findings showed that simple linear-log functions best model recovery rates reflecting primary succession trajectories caused by extreme disturbance and damage. Regression tree analyses showed that despite secondary disturbances, vegetation recovery in both the short and long-term is still dominated by eruption disturbance type and elevation. Finally, compared to NDVI, NBR is a better indicator of structural vegetation regrowth for the early years of revegetation.

Identifying a suitable revegetation method for soil organic carbon, nitrogen, and phosphorus sequestration: A 16‐year in situ experiment on abandoned farmland in a semiarid area of the Loess Plateau, China

AbstractLegume pasture species have been widely used to re‐establish vegetation cover and control soil erosion in semiarid degraded ecosystems. Nevertheless, the long‐term effects of revegetation on aboveground biomass (AB) and the soil properties under different topographies remain unclear. We conducted a 16‐year in situ experiment to evaluate soil properties and biomass dynamics under fallow, sweet clover (Melilotus officinalis L.) and alfalfa (Medicago sativa L.), in northeast‐facing, southeast‐facing, and horizontal landscapes from 2003 to 2018. After 16 years of revegetation, soil organic carbon (SOC), soil total nitrogen (TN), soil total phosphorus (TP) concentrations were higher in alfalfa fields in the northeast‐ and southeast‐facing landscapes and greater in sweet clover fields in the horizontal landscape alongside soil profiles. In the 0–20 cm, the SOC, TN, and TP concentrations in alfalfa fields increased at rates of 0.322, 0.034, and 0.010 g kg−1 yr−1 in the northeast‐facing landscape and at rates of 0.189, 0.022, and 0.011 g kg−1 yr−1 in the southeast‐facing landscape. The SOC, TN, and TP concentrations in sweet clover fields increased at rates of 0.129, 0.023, and 0.009 g kg−1 yr−1 in the horizontal. Alfalfa introduction is recommended for northeast‐facing landscapes whereas alfalfa and fallow are recommended in southeast‐facing landscapes, introduce sweet clover is recommended in a horizontal landscape to improve the soil nutrient concentrations at mid‐long time. These results suggest that topography influences vegetation restoration by affecting plant growth and soil nutrient and should be considered during the revegetation process to ensure revegetation success and sustainable land use.

ANALYSIS ON THE CHARACTERISTICS OF EX-MINING SOIL AFTER 5 YEARS AND 10 YEARS OF REVEGETATION

Open-pit mining has affected landscapes and ecosystem balances immensely. The effects are including altered soil surface, decreased soil productivity, soil compaction, erosion and sedimentation, declined biodiversity, as well as deteriorated hydrological, hydrogeological, and atmospheric function of the surrounding area. Reclamation is one of the environmental restoration efforts that could be taken to improve these conditions. Physical and chemical properties of soil are the indicators of soil damage level as well as the success indicator of the reclamation program. This study aims to analyze the changes in post-mining soil characteristics after 5 years and 10 years of revegetation. The sample was selected by the purposive sampling method based on the age of plants and the vegetation density. The physical properties of post-coal soil after 5 years of revegetation are characterized by high soil acidity, low in organic matter (OM)/soil organic carbon (SOC), very low total N (nitrogen), moderate P availability, extremely high K2O, and moderate CEC. Whilst, the post-coal mining soil after 10 years of revegetation is found to be acidic (low pH), with moderate SOC, low total N, low P, very high K2O, and moderate CEC. Heavy metal (Fe, Mn, Al) contents in ex-coal mining reclamation area after 5 years and 10 years revegetation found to be in the high category.&#x0D; &#x0D; Key words: post-mining land, revegetation, soil characteristics

Modified soil physicochemical properties promoted sequestration of organic and inorganic carbon synergistically during revegetation in desertified land

Large-scale revegetation in desertified land might promote the sequestration of global soil carbon, but the influencing factors on inorganic carbon accumulation processes that absorb CO2 through abiotic “inorganic respiration” processes remain unclear. Several study sites were selected in the Mu Us Sandy Land: quicksand land (0 years), semi-fixed sand land (6 years), and three nearby shrub and arbor forest lands (20, 30, and 51 years). During 20–51 years of revegetation, soil organic carbon density (SOCD) and inorganic carbon density (SICD) significantly increased by 2.5–7.5 times and 1.7–7.0 times for shrub forest and 3.1–7.5 times and 2.6–7.8 times for arbor forest compared with quicksand land, but the difference between the two studied forest lands were not statistically significant. After revegetation in desertified land, the content of total nitrogen (TN), available potassium (AK), cation exchange capacity (CEC), clay, Ca2+, and Mg2+ also greatly enhanced, and they were positively correlated with SOC and SIC, while bulk density and pH slightly decreased, which were negatively correlated with SOC and SIC. T-value biplot importance ranking further indicated that TN was the most sensitive factor affecting the accumulation of SOC and SIC, and its contribution rate to SOC and SIC reached 89.8% and 88.1%, respectively. Moreover, SOC was also related to AK, CEC, and clay, while SIC was more affected by clay, Ca2+, and Mg2+ during revegetation. In conclusion, afforestation with shrubs and arbors on the Mu Us Sandy Land promoted the sequestration of SOC and SIC synergistically by modified soil physicochemical properties.

Diversity, structure and composition of vegetation in post-coal mining reclamation area in Sumatra, Indonesia

Abstract. Yuningsih L, Hearmansyah, Ibrahim E, Marsi. 2021. Diversity, structure and composition of vegetation in post-coal mining reclamation area in Sumatra, Indonesia. Biodiversitas 22: 3392-3400. The majority of coal mines are operated through an open-pit system which has a significant impact on the environment. Therefore, reclamation and revegetation activities are required to recover ecological sustainability. This study aimed to analyze the diversity, structure, and composition of vegetation resulting from the post-mining revegetation process in a mining concession in Sumatra, Indonesia at various intervals of post-reclamation periods, namely 11 years, 10 years, 8 years, and 5 years. Data collection was conducted by sampling with a 2.5 percent intensity. The study discovered 23 species of naturally grow understory plants and 25 species of woody plants. The stand structure at the eleventh, tenth, and eighth years of revegetation resembled an inverted J curve. The Species Richness Index (R) was determined to be low, the Shannon diversity index (H’) was is low to moderate, whereas the evenness index was moderate to high. We concluded that the structure of vegetation in the post-mining reclamation region resembled that of a natural forest ecosystem, yet the biodiversity indicators remain low and below those of natural forest. We expected the result of this study can enrich the limited knowledge of the ecology of post-mining reclamation in the tropics.

Long-term revegetation on iron mine tailings in northern Québec and Labrador and its effect on arbuscular mycorrhizal fungi

The ecological restoration of mine tailings requires the seeding of suitable plant species and the presence of root microbial symbionts to successfully establish vegetation communities. Here we characterized 29 years of revegetation on four iron mine tailings located within the boreal-taïga transition zone of Québec and Labrador, Canada, by measuring the diversity and relative cover of plant species and the root colonization and diversity of arbuscular mycorrhizal fungi (AMF).In the first year after revegetation, over 75% of the plant cover was composed of seeded annuals. During the second year, the seeded biennial Secale cereale covered about 20% of the plots, whereas the seeded and non-seeded perennials represented respectively 50% and 25% of the plant cover. Three to four years after revegetation, the plant cover was composed of about 75% seeded and 25% non-seeded perennials. Five to nine years after revegetation, plant coverage shifted to about 50% seeded and 50% non-seeded perennials, and the first woody plant to colonize these tailings, Salix sp., covered 5%. After ten years of revegetation, non-seeded perennials represented 65% of the plant cover.Root colonization by AMF increased simultaneously with the coverage of perennial species. Percentage of root mycorrhization increased from 0 to 20% during the first two years to 50-55% during years 5 to 9 and up to a maximum of 75% after ten years. We identified Claroideoglomus (mostly C. claroideum) and Rhizophagus (mostly R. intraradices) as the most frequent AMF genera. Nonetheless, Rhizophagus was only detected in plots monitored over five years post-revegetation, suggesting that this genus is best adapted to the mid-term survival of herbaceous perennials on these areas. Two years after revegetation, 50-75% AMF hyphae, 25-30% arbuscules and only 1-12% vesicles were detected in roots. From three to twenty-nine years after revegetation, 40% hyphae, 30% arbuscules and up to 30% vesicles were detected in roots sampled in late summer. 30% of vesicles were also detected in roots sampled in early summer, suggesting that the intraradical phase of AMF life cycle in this northern region can span a two-year period.Our results demonstrate the efficacy of the agronomic method that has been used for over 25 years by Irrigation NORCO for the ecological restoration of iron mine tailings in this northern region of Canada.

Plant biomass allocation and driving factors of grassland revegetation in a Qinghai‐Tibetan Plateau chronosequence

AbstractBiomass allocation is a key factor in understanding how ecosystems respond to changing environmental conditions. The role of soil chemistry in the above‐ and belowground plant biomass allocation in restoring grassland is still incompletely characterized. Consequently, it has led to two competing hypotheses for biomass allocation: optimal partitioning, where the plants allocate biomass preferentially to optimize resource use; and the isometric hypothesis, which postulates that biomass allocation between roots and shoots is fixed. Here we tested these hypotheses over a chronosequence of alpine grasslandsion undergoing restoration in the Qinghai‐Tibetan Plateau, these range from severely degraded to those with 18 years of revegetation with an intact grassland (as a reference). A high proportion of biomass was allocated to the roots in the revegetated grasslands, and more biomass to shoots in the degraded and intact grasslands. The grasslands gradually decreased their root to shoot ratio as revegetation continued, with the lowest value in year 18 of revegetation. Our results showed that aboveground biomass (AGB) was increased by available phosphorus (P), soil moisture, and negatively related to bulk density, while belowground biomass (BGB) was positively impacted by total P and negatively by nitrate nitrogen (N). The trade‐off between them was positively associated with available P and nitrate‐N, and soil nutrient availability is more linked to increased AGB relative to BGB. Our study indicates that biomass allocation is highly variable during the revegetation period from degraded grassland, and is linked with soil properties, thus supporting the optimal partitioning hypothesis.

Assessment of Forest Ecosystem Development in Coal Mine Degraded Land by Using Integrated Mine Soil Quality Index (IMSQI): The Evidence from India

Research highlights: (1) Ecosystem development assessed in an afforested post-mining site. (2) Soil organic carbon (SOC) and total nitrogen (TN) stock reached close to the reference forest site after 25 years of afforestation. (3) Integrated mine soil quality index is developed to assess the reclamation success. Background and Objectives: Estimation of the mine soil quality is one of the most important criterions for evaluating the reclamation success and restoration of novel ecosystems of the post-industrial degraded lands. The aim of this long-term experiment was to investigate the influence of revegetation on Technosol (defined as anthropogenic soil resulted from reclamation of mine spoil materials) as the basic ecosystem development. Materials and Methods: A field study was carried out in the chronosequence afforested post-mining sites (5, 10, 25 years) and compared with natural forest site. We assessed the physicochemical properties and nutrient stock of mine soil and estimated general mine soil quality by using an integrated mine soil quality index (IMSQI). The studies were fully randomized in the chronosequence of afforested post-mining sites. Results: Nutrient dynamics and soil properties (physicochemical and biological) were recovered with the increase age of reclamation. Soil organic carbon (SOC) stock significantly increased from 9.11 Mg C ha−1 in 5 years to 41.37 Mg C ha−1 after 25 years of afforestation. Likewise, total nitrogen (TN) stock significantly increased from 1.06 Mg N ha−1 in 5 years to 4.45 Mg N ha−1 after 25 years of revegetation. Ecosystem carbon pool enhanced at a rate of 6.2 Mg C ha−1 year−1. A Principal Component Analysis (PCA)-based IMSQ index was employed to assess the reclamation success. The most influential properties controlling the health of reclaimed coal mine soil are fine earth fraction, moisture content, SOC and dehydrogenase activity. IMSQ index values are validated with vegetation characteristics. The estimated IMSQI ranged from 0.455 in 5-year-old (RMS5) to 0.746 in 25-year-old reclaimed dump (RMS25). Conclusions: A 25-year-old reclaimed dump having greater IMSQI (0.746) than reference forest soils (0.695) suggested the aptness of revegetation to retrieve soil quality and function in derelict mine land.

Morphometry and size distribution of aggregates from a Typic Hapludult soil under natural secondary forest, implanted leguminous trees and degraded pasture in the Atlantic coast of Brazil

Revegetation of degraded land can in long-term improve the soil attributes compared to the initial condition. This study aimed to evaluate the efficiency of revegetation with leguminous trees to recover the structural quality of a Typic Hapludult soil. For this purpose, morphometric and size-classes distribution analyzes of soil aggregates were performed on soil samples collected from layers 0–0.10 m and 0.10–0.20 m depth. Three areas revegetated with leguminous trees 17 years earlier (Acacia auriculiformis, Mimosa caesalpiniifolia and Inga ssp.) and two reference areas (forest and pasture) were studied. The soil under leguminous trees showed larger aggregates than the soil under forest and pasture, with overall averages by grouping the former higher than those by grouping the latter around 31.6% for the weighted mean diameter and 47.6% for the geometric mean diameter. Aggregate morphometric variables obtained from image analysis were correlated to each other (such as circularity versus roundness, in all five size classes, with values ranging from R = 0.25⁎ to R = 0.72⁎⁎), and also to other soil physical and chemical attributes. As a general rule for all five aggregate size classes studied, both roundness and circularity increased with the increase in the aggregates diameter, the soil densification status, the soil richness in organic matter, the exchangeable cations content and the particle surface electronegativity. The aggregate morphometric variables of the two studied soil layers, analyzed by multivariate statistical tools, led to a consistent distinction between sites, grouping forests and pastures apart from the leguminous tree covers. Thus, it could be concluded that after 17 years of revegetation these leguminous trees changed the soil initially under pasture but in a divergent way in relation to the soil under forest.

Verifying the Utility of Black Locust (Robinia pseudoacacia L.) in the Reclamation of a Lignite Combustion Waste Disposal Site in Central European Conditions

N-fixing tree species, such as black locust, have achieved very promising results in the reclamation of technosols, especially those at combustion waste disposal sites, which have extremely poor nutrients and adverse physicochemical parameters. This paper presents an assessment of the survival rates, growth parameters, and quality and vitality of and nutrient supply (NPK) to black locust (Robinia pseudoacacia L.) specimens that were experimentally planted on a lignite combustion waste disposal site. The black locust seedlings were introduced directly into the combustion waste using two variants of NPK (7% N, 5.5% P2O5, and 9% K2O) fertilisation, at doses of 250 and 500 kg ha−1, and in control plots with no mineral fertilisation. No significant impacts of the applied mineral fertilisation were found on the soil properties, growth parameters, or nutrient supplies to the trees. Black locust introduced to the landfill after three years of revegetation was characterised by a very high survival rate of 95%–100%, as well as good growth parameters (height and diameter at the root collar). Nutrient supply was determined on the basis of the chemical composition of the leaves, which indicated an adequate supply of nitrogen, similar to levels found under natural conditions. In the case of K and P, the supply levels were lower than optimal when compared with data from the literature. However, at this initial stage of tree development on the combustion waste disposal site, nutrient supply is similar on all variants and is not a critical factor for successful black locust introduction. We suggest using growth parameters, survival, and vitality of trees as decisive factors for the reclamation of combustion waste landfill sites strategy. All these factors confirmed the usefulness of black locust to the reclamation of combustion waste disposal sites.

RETRACTED: Study on the throughfall, stemflow, and interception of two shrubs in the semiarid Loess region of China

Abstract The Loess Plateau, China, has been subject to 40 years of re-vegetation predominantly with the xerophytic shrubs Caragana korshinskii and Hippophae rhamnoides. Throughfall, stemflow, canopy interception, and water storage capacity experiments for the two shrubs were conducted from May to September during the period 2009–2013. The results showed that the throughfall percentages averaged 62.4% and 70.1% of gross rainfall for H. rhamnoides and C. korshinskii, respectively, while stemflow accounted for 2.4% and 6.7% of the gross rainfall for the two shrubs. The rainfall threshold for stemflow generation was 2.46 and 1.06 mm for H. rhamnoides and C. korshinskii, respectively. The wetting front depths for the two shrubs in the area around the stems were deeper than away from the shrubs. The averaged percentages of interception loss in H. rhamnoides and C. korshinskii were 35.2% and 23.2%. Additionally, H. rhamnoides had greater water storage capacity per leaf area for each simulated rainfall intensity (mean, 0.59 mm; range, 0.28–0.88 mm) than C. korshinskii (mean, 0.44 mm; range, 0.26–0.52 mm). Canopy water storage varied temporally with the eight simulated rainfall intensities. For all the tested rainfall intensities, H. rhamnoides could store more water per dry biomass (mean, 0.72 g−1; range, 0.39–1.06 g−1) than C. korshinskii (mean, 0.49 g−1; range, 0.31–0.69 g−1). The present study can inform re-vegetation projects, water budget analyses, and modeling efforts aimed at understanding rainfall water movement within shrub communities in the semiarid Chinese Loess Plateau, China.