Revegetation Of Areas Research Articles

Soil moisture content and its temporal stability in an arid aerial seeding afforestation area after 30 years vegetation restoration in China

Soil moisture is a critical factor for vegetation restoration in arid regions. Poorly planned artificial sand-fixing vegetation systems often exacerbate soil moisture depletion, leading to further degradation. In this study, soil moisture content at various depths was continuously monitored from June to October 2023 in four key community plots—Corethrodendron scoparium, Calligonum mongolicum, and Artemisia ordosica, and bare sand—in a 31-year-old revegetated area located on the northeastern edge of the Tengger Desert. We analyzed the distribution and dynamic changes of soil moisture across the different and evaluated its temporal stability. The representative soil moisture depth was determined by using the coefficient of determination (R2) and the Nash-Sutcliffe efficiency (NSE). The results showed significant differences in soil moisture among the four plots. The bare sand plot had the highest soil water storage in the 0-200 cm layer, at 46.37 mm. In contrast, the Corethrodendron scoparium, Calligonum mongolicum, and Artemisia ordosicaa plots had similar soil water storage values ranging from 33.50 to 33.67 mm, indicating that vegetation restoration has increased soil moisture absorption by an average of 27.4%. Analysis using relative difference and Spearman rank correlation methods revealed varying levels of temporal stability in soil moisture across different soil depths and plots. The Corethrodendron scoparium and bare sand plots showed higher temporal stability compared to the Calligonum mongolicum and Artemisia ordosica plots. The representative depths of temporal stability for the four plots were determined to be 100 cm, 150 cm, 20 cm, and 100 cm, respectively.

Can green firebreaks help balance biodiversity, carbon storage and wildfire risk?

Green firebreaks (strategically placed plantings of low-flammability vegetation) are designed to reduce the rate of fire spread and thereby increase the suppressibility of fires. Successful examples have led to some fire-prone regions investing heavily in the establishment of green firebreaks as a method of reducing fire risk while improving biodiversity and carbon storage. However, beyond small-scale case studies there has been little research quantitatively exploring the interactions among biodiversity, carbon, and wildfire risk in relation to green firebreaks. Here, we combine a Bayesian Network (BN) analysis, and fire simulations in PHOENIX RapidFire (hereafter Phoenix), to identify planting designs that reduce wildfire risks while also providing positive biodiversity and carbon outcomes. Using a BN analysis, we prioritised optimal planting designs as the combination of elements (e.g., stem density, distance from houses, shrub design, age etc.) that delivered the greatest increase in biodiversity and carbon while reducing fire risk to people and property for eight sites across south-eastern Australia. We ranked combinations of planting designs, prioritising house, and life loss first, to identify optimal designs. Optimal planting designs varied among sites, although the design elements that best reduced risk to houses and lives were consistent. These elements included ‘scattered’ shrubs and planting densities of trees consistent with an open forest structure. Estimated fuel loads for the optimal planting design at each site were used to create a simulated revegetation area in Phoenix. We simulated fire behaviour in Phoenix across a grid of ∼1000 ignitions for each site, and for up to 54 historic weather conditions for a 'current fuel’ scenario (no green firebreaks present) compared with a ‘green firebreak fuel’ scenario. We found that the establishment of a green firebreak did not result in significant changes to fire behaviour at most sites. In some cases, it reduced risk to people and property, and where fire behaviour did change in terms of intensity, frequency, ember attack and overall risk, the differences relative to the current fuel scenario were less than two percent. Overall, simulated green firebreaks in most cases were found to provide biodiversity and carbon benefits without increasing fire risk. These findings illustrate their potential as an effective nature-based solution for managing multiple priorities; however, further testing of real plantings is required to evaluate this potential as an at-scale solution.

PENGARUH REVEGETASI TERHADAP SIFAT-SIFAT TANAH PADA LAHAN BEKAS TAMBANG TEMBAGA DI NUSA TENGGARA BARAT

Copper mining activities mainly using open-pit techniques, lead to environmental issues such as overburden waste in waste dump areas that have potential to generate acid mine drainage (AMD), which can decrease soil pH and increase heavy metal toxicity. Reclamation efforts, including revegetation using pioneer plants and cover crops are necessary to restore degraded land in waste dump areas. The aim of this research is to analyze soil physical and chemical properties improvement after revegetation on copper post-mining land as an evaluation and to provide recommendations for future reclamation. The research was carried out by analyzing and interpreting laboratory data from soil observations in revegetation areas for the 2016, 2018, 2019 and 2020 planting years, as well as natural forests belonging to PT. Amman Mineral Nusa Tenggara. Revegetation of copper post-mining land does not show a significant improvement in soil physical properties because improving physical properties takes quite a long time, especially in post-mining areas with heavy structural damage. Soil chemical properties analysis shows that revegetation can increase base saturation (BS), cation exchange capacity (CEC), exch-Ca, exch-Mg, and reduce soil Al saturation. In contrast, soil pH, organic-C, total-N, and soil available-P in the revegetation area did not increase as the revegetation age increased. The effect of revegetation appears to be more significant at the age of 2 to 3 years. However, based on the Tukey test, the age of revegetation mostly does not have a significant effect on enhancing soil chemical properties.

Estimation of Biomass and Carbon Stock Using NDVI from Multispectral Camera in the Revegetation Area of PT Berau Coal

Estimation of Biomass and Carbon Stock Using NDVI from Multispectral Camera in the Revegetation Area of PT Berau Coal

Capung (Ordo: Odonata) di Kawasan Reklamasi Bekas Tambang Timah, Belinyu, Bangka

Dragonflies are bioindicator insects that are known to be sensitive to the environment and their existence is influenced by habitat conditions. The potential of dragonflies as a bioindicator for the success of reclamation efforts for former tin mining on Bangka Island needs to be studied. This research aims to record the diversity of dragonflies and damselflies in reclaimed land covering an area of ±15.25 ha and aged ±16 years as one component to enrich the criteria for assessing the success of revegetation of ex-tin mining land. This research was conducted in the rainy season, January-March 2023. For three weeks, Schnabel's visual encounter survey (VES) and capture-mark-release-recapture (CMRR) methods were chosen to observe five transect lines, respectively non-revegetation areas, horticultural and fruit revegetation areas, oil palm revegetation areas, kolong with tilapia fish, and kolong with human activities. This research recorded 19 species of dragonflies and 6 species of damselflies, or around 6.5% of the dragonflies and 2.0% of the damselfly species on the island of Sumatra. The most dominant species are Neurothemis fluctuans and Ceriagrion cerinorubellum. The number of species and number of individual dragonflies is thought to be related to the age of reclamation, and has the potential to be an indicator of the success of ex-tin mining reclamation land. Keywords:“Area Type”; “Bangka”; “Bioindicator”; “Dragonfly”; “Ex-Mined Land Reclamation”

EVALUASI PELAKSANAAN REVEGETASI PADA LAHAN PASCATAMBANG BATUBARA (STUDI KASUS DI PT. X DI KABUPATEN TANAH BUMBU PROVINSI KALIMANTAN SELATAN)

Coal mining company in PT. X, in Tanah Bumbu District, South Kalimantan Province, uses the open-pit mining method, causing the initial vegetation loss of an area. PT. X has rehabilitated areas affected by mining by reclamation and revegetation to comply with government regulations. The types of vegetation that grew in the post-mining land revegetation area in the planting years 2012, 2014 and 2016 were acacia (Acacia mangium WILLD), trambesi (Samanea saman), sea sengon (Paraserianthes falcataria), and woody and fruit plants such as mahogany (Swietenia macrophylla), agarwood (Aquilaria moluccensis), meranti (Shorea Spp.), sungkai (Peronema canescens), rubber (Hevea brasiliensis), durian (Durio zibethinus), jackfruit (Artocarpus heterophylla), cashew (Anacardium occidentale), mango (Mengifera indica) and galam (Melaleuca cajuputi). Land characteristics have a steep slope of 35° in 2012 and range from 5°-20° in 2014 and 2016 The drainage system for planting years 2012, 2014 and 2016 looks good no erosion strains, planting years 2014 sites are flooded. The results of soil analysis are pH 4.48 - 4.97; the value of C-organic compounds 0.20% (very low) - 1.33% (medium); P2O5 1.89 mg/100g-1 (very low) - 40.10 mg/100g-1 (high); K2O with values of 8.57 mg/100g-1 (low) - 15.50 mg/100g-1 (medium), 0.20 me/100g-1 (very low) – 19.59 me/100g-1 (low); Mg-exchange at a value of 0.10 me/100g-1 (very low) - 0.20 me/100g-1 (low); Na-exchange of 0.05 me/100g-1 - 0.10 me/100g-1 is low; K-exchange with a value of 0.03 me/100g-1 - 0.05 me/100g-1 is very low, CEC 27.85 me/100g-1 - 52.48 me/100g-1 is low, saturation 0.95% (very low) - 41.56 (high). Based on the success rate of reclamation with revegetation parameters according to the Regulation of the Minister of Forestry No.P.60/Menhut-II/2009, it can be concluded that the success of revegetation obtained for the overall value with an overall value of 24 out of the target value of 50 with a percentage of plant growth of 27%, then the success value of revegetation is categorized as low.

Spatiotemporal characteristics of evaporation in China and its response to revegetation in a typical region by a generalized complementary approach

The generalized nonlinear advection aridity (GNAA) model has been widely applied for evaporation estimations and drought assessments at regional and global scales. Here, the GNAA model was combined with a semi-empirical function for the parameter αe-B to estimate actual evaporation (E) in nine Level-I water resources regions and one typical revegetation area (i.e., the Loess Plateau) in China. The results showed that the semi-empirical function for αe-B with aridity index rescaled the original independent variable (xB) in GNAA; thus, the model satisfied the boundary condition of “y = 0, at xB-αf =0”. Moreover, the data points of E/Epa (Epa: apparent potential evaporation) and Epo/Epa (Epo: potential evaporation) were captured well by the GNAA curve with the semi-empirical function of αe-B. Further, the GNAA model showed high accuracy in simulating evaporation (ECR-B) when compared with the water balance equation, with the mean absolute error, root mean square error, and Nash-Sutcliffe efficiency values being 52 mm, 66 mm, and 0.84 respectively, over 49 basins. The multi-year mean ECR-B was 443.1 ± 14.7 mm/yr and 431.6 ± 21.2 mm/yr across China and Loess Plateau, respectively. Moreover, the annual ECR-B showed a significant upward trend during 1982–2017, and ECR-B increased rapidly before 1998, but decreased slightly after 1998 when considering 1998 as the turning point across China. Since the implementation of the large scale “Grain for Green” project on the Loess Plateau, nomalized difference vegetation index (NDVI) and precipitation increased significantly, while ECR-B showed no significant increases in both China and Loess Plateau. For the Loess Plateau, annual precipitation increased faster than annual evaporation, implying that water yield may increase. Overall, the findings would assist in clarifying the characteristics of evaporation across China and contribute to better management and sustainable utilization of regional water resources.

Vegetation restoration in dryland with shrub serves as a carbon sink: Evidence from a 13‐year observation at the Tengger Desert of Northern China

AbstractDryland area accounts for approximately 40% of worldwide land area, which plays a significant role in regulating the carbon sequestration capacity of land. Vegetation restoration in drylands adopted to prevent land degradation, and may also serve as a carbon sink in the earlier stage. However, the persistence of the carbon sink for the revegetated ecosystem in drylands is still unknown. Can the well‐established restoration vegetation in dryland areas serve as a carbon sink in long‐run? To address this question, we investigated the carbon sequestration capacity of planted vegetation in dryland areas with 13 years of observation (2009–2021) for established vegetation restoration, which began in 1989. We found that the revegetation area serves as a carbon sink in all years. The mean annual net ecosystem productivity (NEP) is 91.61 ± 36.17 gC m−2 yr−1 (mean ± standard deviation). Annual NEP showed a significant increasing trend over the study period with a rate of 5.65 gC m−2 yr−1 yr−1 (p < 0.05). The increase in spring temperature, the earlier start of net carbon uptake and the longer duration of net carbon uptake contribute to the gradual trend of NEP. The amount of annual NEP is predominantly determined by summer precipitation. Meanwhile, our results revealed that the increase in net carbon uptake by revegetation did not lead to excessive consumption of water resources. Our results have suggested that appropriate vegetation restoration in arid areas can increase ecosystem carbon sequestration over longer timescales and mitigate climate change, with relatively low environmental consequences and risks. Considering the vast area of degraded land in the global drylands, the carbon sequestration effect of this model should be given more attention.

Natural revegetation has dominated annual runoff reduction since the Grain for Green Program began in the Jing River Basin, Northwest China

The Grain for Green Program (GFGP) has successfully increased the vegetation cover in northern China over the last two decades through large-scale natural and artificial revegetation approaches. Unfortunately, an obvious runoff reduction has been observed in many basins, especially on the semiarid Loess Plateau. Past studies generally attributed this runoff reduction to the artificial revegetation of the GFGP, i.e., the land cover type change from cropland to forest, since there was no significant annual precipitation decrease. Such cognition has led to widespread concern about the hydrological effects of the GFGP. In fact, in addition to artificial revegetation, natural revegetation relies on natural processes of vegetation succession without land cover type changes directed by humans. Therefore, it is necessary to separate and quantify the contributions of natural and artificial revegetation to runoff reduction to assess the GFGP and optimize revegetation in the future. In this study, the contributions of natural and artificial revegetation to annual runoff change after the implementation of the GFGP were quantified in fifteen subbasins of the Jing River Basin in the central Loess Plateau. The mean annual runoff of the Jing River Basin decreased by 11.8 mm after the GFGP, although the climate (precipitation and potential evapotranspiration) inversely increased the mean annual runoff by 6.6 mm. This is due to that the direct effect of climate change was much less than the ecohydrological effect of revegetation on runoff reduction, i.e., the revegetation caused the mean annual runoff reduction of 18.4 mm. Natural revegetation (50.5% of basin area) was the dominant reason for runoff reduction rather than artificial revegetation (9% of basin area). The natural revegetated area with vegetation quality improvement, i.e., an NDVI increase without land cover type change, contributed to a runoff reduction of 15.5 mm, accounting for 131.1% of the total runoff reduction after the GFGP, and the grassland of natural revegetation was the main vegetation type, with runoff reductions of 9.8 mm. However, artificial revegetation by area increase and quality improvement, i.e., NDVI increase, contributed to a runoff reduction of 8.4 mm, accounting for 49.6% of the total runoff reduction. These results demonstrated that the GFGP needs to be properly adjusted, i.e., natural revegetated areas should be opened in a timely manner and properly utilized, and improving vegetation quality improvement rather than increasing vegetation area would be a priority management measure in artificial revegetated areas.

Assessing the potential of red mud and dehydrated mineral mud mixtures as soil matrix for revegetation

The disposal of red mud (RM) and dehydrated mineral mud (DM) presents a significant challenge for the global alumina industry. This study proposes a novel disposal method for RM and DM, which uses mixtures of RM and DM as a soil matrix for revegetation in the mining area. RM mixed with DM effectively alleviated its salinity and alkalinity. X-ray diffraction analysis indicated that reduction of salinity and alkalinity may be due to the release of chemical alkali from sodalite and cancrinite. Applications of ferric chloride (FeCl3), gypsum, and organic fertilizer (OF) improved the physicochemical properties of the RM–DM mixtures. FeCl3 significantly reduced available Cd, As, Cr, and Pb content in the RM–DM, while OF significantly increased the cation exchange capacity, microbial carbon and nitrogen, and aggregate stability (p < 0.05). Micro-computed tomography and nuclear magnetic resonance analysis showed that amendment with OF and FeCl3 increased the porosity, pore diameter, and hydraulic conductivity in the RM–DM mixture. The RM-DM mixtures had low leaching of toxic elements, indicating low environmental risk. Ryegrass grew well in the RM–DM mixture at a ratio of 1:3. OF and FeCl3 significantly increased the ryegrass biomass (p < 0.05). These results suggested that RM–DM amended with OF and FeCl3 has a potential application in the revegetation of areas after bauxite mining.

Rehabilitation plan for coal pit revegetation area East Kalimantan

The degraded mining area, especially the disposal area, must be reclaimed to preserve the possibility of its subsequent use in the future. The open pit rehabilition must ensure post-mining contributes powerfully to the ecosystem by restoring the production capacity and stability of the area. The exercise was applied to a nearly 0.5 Ha of open-pit coal mine conducted in cooperation between Korea and Indonesia to create a production forest that can ultimately support the environment. The objective of this work was to design mine pit reclamation plan through characterization physically and chemically the location by regenerating, checking the drainage system, analyzing soil fertility and the possibility of soil contamination and discovering fast growing local crop and forest plant species. The main focus is more on analyzing the soil condition affected by the acid mine drainage problem. The results showed that the northern restoration target site had the steep slope, characterized as acidic soil (pH was 4.2 – 4.6) with low exchangeable cation and low phosphate availability. The heavy metals did not exceed the contamination limit, so separate processing to prevent leaching of heavy metals is not required. Routine monitoring of the drainage system is important because it will affect the watering frequency and leaching control. Understanding the step by step mine rehabilitation can assist in designing reclamation efforts especially for revegetation purpose.

KESESUAIAN LAHAN REKLAMASI UNTUK REVEGETASI TANAMAN MAHONI (SWIETANIA MACROPHYLLA) DAN TANAMAN SUNGKAI (PARONEMA CANESCENS) PADA PT. BHUMI RANTAU ENERGI DI KABUPATEN TAPIN PROVINSI KALIMANTAN SELATAN

The mining sector is one of the main economic sectors in Indonesia, including coal. Given the importance of ecosystem sustainability, reclamation and revegetation activities are very important. The aims of this study were (1) to analyze the characteristics of soil fertility at the reclamation and revegetation sites of PT. Bhumi Rantau Energi and (2) analyze land suitability of PT. Bhumi Rantau Energi which has been planted with mahogany (Swietenia macrophylla) and sungkai (Peronema canescens) plants.. The approach used in this study is a quantitative method and descriptive analysis, with a research implementation time of 3 (three) months. The research was conducted at Rinjani and Merapi which is a reclamation and revegetation area of PT. Bhumi Overseas Energy. The objects in this study were soil samples in Rinjani D3 planting year 2017 with an area of 2.39 ha and measurements of Mahogany, Sungkai and Sengon vegetation on Rinjani D3 planting year 2017 with an area of 2.39 ha, Rinjani E2 planting year 2018 with an area of 6, 40 ha and Merapi F9 planting year 2019 with an area of 18.62 ha. The results showed that the fertility of the soil was in the low fertility class. However, the success of growing the main types of sengon and inlay types of mahogany and sungkai in post-coal mining revegetation land was in the high category. Sungkai inserts have better diameter and plant height than mahogany inserts. For land suitability results, the mahogany insert is thought to be relatively slightly better than the sungkai plant. Parameter differences that occur in the annual average rainfall. The results of the land suitability analysis obtained direct engineering improvements to be carried out by improving the parameters of soil pH, soil fertility and soil depth.

Characteristics of Soil Microbial Community in Different Habitats in the Process of Ecological Restoration of Haifeng Wetland in Guangdong

Soil microorganisms can respond to changes in wetland ecosystem quality and functional evolution sensitively. To explore the changes and response mechanisms of soil microorganisms under ecological restoration measures, the characteristics of the soil microbial community and their influencing factors were analyzed using high-throughput sequencing technology in four different habitats (revegetation area, native vegetation area, tidal creek, and tidal flat) during the ecological restoration process in Haifeng wetland in Guangdong. The results showed that:soil physicochemical properties of the four different habitats were significantly different; the contents of TC, TN, TOC, and TK in the tidal creek were significantly higher than those in the other habitats; and the contents of TC, TN, and TP in the revegetation restoration area were significantly higher than those in the tidal flat. The EC values in the tidal creeks and tidal flat were significantly higher than those in the revegetation area and the native vegetation area. The diversity index and abundance of soil bacteria in the tidal creek were the highest, and those in the vegetation restoration area were significantly higher than those in the bare flat. The archaea in the tidal creek were significantly more complex than those in the other three habitats, and the fungal community diversity index and abundance in the native vegetation area were significantly higher than those in the other areas, which had the most complex community structure. TN and TC were the main factors affecting the bacterial community, whereas TN and EC were the main factors affecting the archaea community, and pH, TN, and TP were the key factors affecting the fungal community. In conclusion, the planting of vegetation on the tidal flat increased the diversity and richness of the soil microbial community during the process of ecological restoration, indicating that it has resulted in positive feedback on ecological restoration so far. The results of this study can provide a theoretical basis for the selection of ecological restoration strategies for the tidal flat.

PERKEMBANGAN SUKSESI VEGETASI DI AREA REVEGETASI LAHAN PASCATAMBANG BATUBARA (STUDI KASUS DI PT AMANAH ANUGERAH ADI MULIA KABUPATEN TANAH LAUT)

The purpose of the study was to analyze the development of vegetation succession in the post-coal mining revegetation area of PT Amanah Anugerah Adi Mulia. The method used to collect data in the revegetation area is the Nested Sampling. The data collected in the form of individuals number, types of vegetation, and diameters of poles and trees. Data were analyzed by tabulating matrix and Indeks Nilai Penting (INP). There are 8 main types of revegetation plants, 16 types of natural growth and 40 types of undergrowth plants. There is a trend of increasing the number of plants that grow naturally at the level of seedlings, saplings, poles and trees in the revegetation area. Revegetation plants aged 7 years had the highest number of species. The dominant species at 1 year revegetation age for seedlings was sengon buto (Enterolobium cyclocarpum) with INP= 86,01%, sapling was E. cyclocarpum with INP= 106,15%. The dominant species at 3 years of revegetation age for seedlings was calliandra (Calliandra calothyrsus) with INP value = 75,57 %, sapling was sengon laut (Paraserianthes falcataria) with INP = 56,73%, pole level was P. falcataria species with INP = 162,85%. The dominant species at 5 years of revegetation age for seedlings was sisir liar (Cudrania cochinchinensis) with INP value = 108,38 %, sapling was C. cochinchinensis with INP = 103,59 %, pole level was mangium (Acacia mangium) with INP = 229,58 %, the tree level is mangium with INP = 211,74%. The dominant species at 7 years of revegetation age for seedlings was mahang (Macaranga gigantea) with INP value = 53,32%, sapling was M. gigantea with INP = 44,31 %, pole level was A. mangium with INP = 98,29 % , the tree level is P. falcataria with INP = 163,15%. Revegetation can facilitate the succession process in post-mining land.

Litter decomposition and its effects on soil microbial community in Shapotou area, China

We investigated the decomposition characteristics of Eragrostis minor, mosses, and leaves of Artemisia ordosica with litterbag method in the sand-binding revegetation area, southeastern edge of the Tengger Desert, and further examined their effects on soil microbial communities using the Illumina MiSeq sequencing method. The results showed that the decomposition duration and litter types significantly affected litter decomposition rate. Mosses had the lowest decomposition rate, with a mass loss ratio of only 15.4% after decomposition for 13 months. The average decomposition rates of E. minor and leaves of A. ordosica were 4.9 and 3.4-fold of that of mosses, respectively. During decomposition for 11 months, the dominant bacterial phyla were Actinomycota and Proteobacteria, while that of the fungal community was Ascomycota. Moss decomposition significantly increased the relative abundance of Bacteroidetes and Chloroflexi, but remarkedly decreased the abundance of Basidiomycetes. The diversity and richness of bacterial and fungal communities significantly increased after litter decomposition. The compositional changes of fungal community were significant among litters, but that of bacterial community was not. There was a negative correlation between decomposition rate and the diversity and richness of bacterial and fungal communities. Plant polysaccharides, total phosphorus, soil pH, microbial biomass nitrogen, and soil ammonium content were the main factors affecting microbial community structure. Litter decomposition changed the composition and interspecific similarity within microbial communities, as well as increased the diversity and richness of soil microbial communities, and thus would promote the restoration of soil habitat.

Soil denitrification rates are more sensitive to hydrological changes than restoration approaches in a unique riparian zone

Abstract Riparian zones, an aquatic‐terrestrial interface, can intercept more than half of nitrogen (N) exported from terrestrial ecosystems to adjacent rivers, primarily by denitrification processes. However, damming has disrupted natural patterns and processes of flooding and vegetation community assemblages, and yet little is known about how hydrological changes and ecosystem restoration affect the biogeochemical functioning in the riparian ecosystems. We conducted an in situ experiment to evaluate the effects of hydrological change (e.g. altering flooding intensity and frequency) and restoration approaches (e.g. natural regeneration and active revegetation) on denitrification rates and the abundance of denitrifier genes in the riparian zone of the Three Gorges Reservoir, China. Our results showed that active revegetation did not significantly increase denitrification rates compared to the natural regeneration, but their underlying mechanism was different. At the natural regeneration area, the denitrification rate was primarily regulated by soil properties and abundance of nosZ gene, while at the active revegetation area, it was controlled merely by the abundance of nosZ gene. In addition, vegetation types showed little effect on the soil denitrification process, and the denitrification rate decreased with flooding intensity by reducing denitrifier gene abundance. The periodic flooding treatment doubled the denitrification rate compared with the no flooding treatment, which might be attributed to the enhancement of soil carbon availability. Our results suggest that in terms of N removal via denitrification processes, natural regeneration is a priority approach to restoring degraded riparian ecosystems. Read the free Plain Language Summary for this article on the Journal blog.

Managing Bank Soil on Surface Mining Operation with USLE Method

The most valuable layer in mining activities is topsoil, so adequate management is needed, especially in maintaining its quality, quantity, and mechanical properties. The land is used for revegetation, which supports post-mining success and can return the land to its original condition. This process starts by placing the soil in one area, and when the revegetation area is ready, it is removed. Soil is loose and has low mechanical properties, so it is susceptible to erosion when it rains. The research objective is to manage topsoil to maintain quantity and quality, and erosion and sediment load can be reduced. The analysis was carried out using the Universal Soil Loss Equation (USLE) method by changing the variable C (cover factor) through the option of planting Cymbopogon nardus. This plant has long roots that can increase soil cohesion, grows fast, and has economic value. Planting Cymbopogon nardus with a spacing of 0.8 m can reduce erosion by 175.67%, less than the bare soil condition. The value of the C factor decreased from 1 to 0.759 after planting Cymbopogon nardus with that spacing. The decrease in monthly erosion is 14.72-49.78 tons/ha/month, with an average decrease of 30.14 tons/ha/month or 361.69 tons/ha/year. Planting Cymbopogon nardus effectively reduces erosion at a lower cost and effort. This plant provides many benefits after leaves and stems can be distilled to produce essential oils.

Vegetation development in post-gold mining revegetation area in Minahasa, North Sulawesi, Indonesia

Abstract. Lestari KG, Budi SW, Suryaningtyas DT, Yudhiman E. 2022. Vegetation development in post-gold mining revegetation area in Minahasa, North Sulawesi, Indonesia. Biodiversitas 23: 3224-3233. Gold mining activities in Indonesia, in many areas, have a negative impact on the environment. Activities that can improve the quality of post-mining land include revegetation activities, which are included in post-mining land reclamation activities. The purpose of this study was to analyze the development of vegetation in post-gold mining revegetation areas. Vegetation data were collected using the plotted line method (natural forest) and the Systematic Sampling method with Random Start (revegetation area). The analysis found that the vegetation structure in the post-gold mining revegetation area aged 3 to 10 years has complete vegetation levels (saplings, saplings, poles, and trees). Compared to natural forest, which only includes 30 tree species and 7 herbaceous, this revegetation region has a greater diversity of species, with 66 tree species and 16 herbaceous. The longer the age of revegetation is not followed by an increase in species and an increase in the value of the species diversity index. However, it is still better than the revegetation at a young age and is closer to the condition of a natural forest. The revegetation area aged 8 and 7 years has a higher number of species than natural forests and other revegetation areas.

Photosynthesis and Leaf Traits of Tree Species Influenced by Green Manure Associated with Soil Treatments

ABSTRACT The use of green manure (GM) associated with soil decompaction treatments has shown to be an alternative to improve soil attributes. This study associated the use of GM with tree species nitrogen-fixing and non-nitrogen-fixing (N-fixing and non-N-fixing, respectively), hypothesizing that non-N-fixing species are more beneficial by GM. The experiment was carried out in a disabled clay extraction deposit. Previously, chemical analysis and mechanical resistance to soil penetration was registered in order to characterize the initial soil properties of the experimental site. The soil treatments were scarification (SCA), scarification + harrowing (SCAH), and subsoiling + harrowing (SUBH) with presence/absence of GM (+GM and -GM, respectively) and four native tree species, N-fixing (Dalbergia ecastophyllum (L.) Taub., Inga laurina (Sw.) Willd., and non-N-fixing (Psidium cattleianum Sabine and Schinus terebinthifolius Raddi), were planted. Growth and leaf traits were measured after 6 and 12 months. The response patterns of leaf attributes were well defined in the non-N-fixing species. Over time, GM increases the level of chlorophyll (Chl) in N-fixing species and, consequently, improves the maximum quantum yield for photosystem II (PSII) primary photochemistry (φPo), quantum yield for PSII electron transport (φEo), the number of active reaction centers (RC/CSo), and the performance index (PI/abs). GM increased these same photochemical parameters in non-N-fixing species after 12 months. The samples cultivated in the SCA and SUBH treatments showed a better performance. The species responded in different ways to GM, which improved the leaf traits in non-N-fixing species. GM improved the leaf traits of N-fixing species. The positive effect of GM over time give us a good alternative for fertilization in revegetation areas. Furthermore, our findings shown that the subsoiling promotes the highest soil decompaction, which associated with GM, can be efficiently used in projects of revegetation of degraded areas.

Structure and putative function of a soil microbial community impacted by the deposition of tailings and subsequent revegetation after the rupture of the Fundao Dam

AbstractThe rupture of the Fundão Dam containing iron‐rich mining tailings, in 2015, was one of the worst environmental disasters in Brazil. The deposition of tailings has generated serious impacts on the soil and, as microorganisms play an important role in these environments, the recovery of the microbial community is a critical step in restoring the soil for sustainable use. Soil microorganisms and their activities are recognized as sensitive bioindicators for environmental changes; however, few experiments have been conducted to investigate the response of the microbial community to the magnitude of the impact caused by the Fundão Dam rupture and the effect of the use of revegetation natural or induced for ecosystem recovery, especially in Brazil. This study aimed to evaluate the dynamics of community structure and putative functions, over time, in response to the deposition of the tailings on the soil by bacterial 16S rRNA sequencing. We evaluated an area affected by tailings, covered with natural and induced revegetation. The results revealed a temporal dynamic of the soil microbiota, which demonstrates that the microbial community structure of these areas differed, mainly in less abundant taxa, and the induced revegetation area was closer to the forest than natural revegetation. These results reveal the importance of implementing revegetation programs to accelerate the initial recovery. Functions related to the use of alternative electron acceptors differed, possibly due to the greater compaction of the affected soil. Despite the improvement of the impacted areas over time, the strong effect of tailings deposition on the bacterial community structure can still be noticed.