Post-mining Soil Research Articles

STUDI KOMPARATIF PERTUMBUHAN RUMPUT MULATO PADA LAHAN PASCA TAMBANG YANG DIBERI PUPUK BERBEDA

To determine the effectiveness of the use of organic fertilizers on the growth rate of grass mulato (brachiaria hybrid cv mulato) which is planted on the soil after mining PT. Vale, bro. located in sorowako, East Luwu Regency, South Sulawesi Province. This Research was conducted using a completely randomized design (CRD) factorial (4 x 3) with 3 times replication for each treatment combination. Factor A as a type of fertilizer and Factor B as a cutting age. Experiments are 36 total units. The results showed that the plant height given liquid organic fertilizer was significantly higher (P <0.01) than the plant height rate in the post-mining soil which was given granular fertilizer. This difference occurs because liquid organic fertilizer is faster absorbed by plants than organic solid fertilizer (granules). Post-mining land which is used as a medium for mulato grass growth is actually not a barrier to use. The conclusion of this research is the use of organic fertilizers in the cultivation of grass mulato (Brachiaria hybrid cv. Mulato) on post-mining land gave a positive response. The use of organic liquid fertilizer provides the best response compared to the control and solid organic fertilizer (granule).

STUDI KOMPARATIF PERTUMBUHAN RUMPUT MULATO PADA LAHAN PASCA TAMBANG YANG DIBERI PUPUK BERBEDA

To determine the effectiveness of the use of organic fertilizers on the growth rate of grass mulato (brachiaria hybrid cv mulato) which is planted on the soil after mining PT. Vale, bro. located in sorowako, East Luwu Regency, South Sulawesi Province. This Research was conducted using a completely randomized design (CRD) factorial (4 x 3) with 3 times replication for each treatment combination. Factor A as a type of fertilizer and Factor B as a cutting age. Experiments are 36 total units. The results showed that the plant height given liquid organic fertilizer was significantly higher (P <0.01) than the plant height rate in the post-mining soil which was given granular fertilizer. This difference occurs because liquid organic fertilizer is faster absorbed by plants than organic solid fertilizer (granules). Post-mining land which is used as a medium for mulato grass growth is actually not a barrier to use. The conclusion of this research is the use of organic fertilizers in the cultivation of grass mulato (Brachiaria hybrid cv. Mulato) on post-mining land gave a positive response. The use of organic liquid fertilizer provides the best response compared to the control and solid organic fertilizer (granule).

Accumulation of As, Ag, Cd, Cu, Pb, and Zn by Native Plants Growing in Soils Contaminated by Mining Environmental Liabilities in the Peruvian Andes.

The capability of native plant species grown in polluted post-mining soils to accumulate metals was evaluated in view of their possible suitability for phytoremediation. The study areas included two environmental liabilities in the Cajamarca region in the Peruvian Andes. The content of As, Ag, Cd, Cu, Pb, and Zn was determined in individual plant organs and correlated with soil characteristics. The degree of the pollution depended on the metal with results ranging from uncontaminated (Cd) to moderately (Zn), strongly (As, Cu), and extremely contaminated (Pb, Ag) soils. The metals were mainly present in the fractions with limited metal mobility. The bioaccumulation of the metals in plants as well the translocation into overground organs was determined. Out of the 21 plants evaluated, Pernettya prostrata and Gaultheria glomerate were suitable for Zn, and Gaultheria glomerata and Festuca sp. for Cd, phytostabilization. The native species applicable for Cd phytoremediation were Ageratina glechonophylla, Bejaria sp., whereas Pernettya prostrata Achyrocline alata, Ageratina fastigiate, Baccharis alnifolia, Calceolaria tetragona, Arenaria digyna, Hypericum laricifolium, Brachyotum radula, and Nicotiana thyrsiflora were suitable for both Cd and Zn. None of the studied plants appeared to be suitable for phytoremediation of Pb, Cu, As and Ag.

Aplication of Soil Productivity Index after Eight Years of Soil Reclamation with Sewage Sludge Amendments

Remediation methods are gaining acceptance as effective and inexpensive techniques used in the reclamation of degraded areas. The reclamation of post-mining sites has become important for the conservation of soil and vegetation. An assessment of potential productivity of plants based on the depth of their root zone is crucial for the validation of properties of post-mining soils. Our aim was to present soil productivity parameters that would facilitate assessment of various post-mining objects. Soil productivity index (SPI) was calculated to assess soil quality, mainly in areas degraded by hard coal mining. It is based on an equation determining the relationship between the productivity index and the physical, chemical, and hydrological properties of soil. Our study demonstrated the positive effects of enriched sewage sludge with amendments on newly formed soil and plants. The soil productivity index was 0.81, demonstrating the suitable condition of the initial soil resulting from reclamation. This parameter might be important for post-industrial reclamation, such as wasteland intended to be transformed into woodland. Considering the composition of sewage sludge amendments, it can be successfully used as an effective method of restoring and improving both the physical and chemical properties of soils, thus effectively replacing mineral fertilisers. The use of sewage sludge in soil reclamation will be an important method of managing this waste material in post-mining areas.

Revegetation of Critical Land with Gaharu (Aquilaria malaccensis) under Various Ameliorants Application

Rehabilitation of post-mining limestone soils is often a challenge due to a lack of nutrients and poor soil humus. The research aims to study the effect of various ameliorants on soil chemical properties, growth, and P uptake of gaharu plant (Aquilaria malaccensis) in post-mining limestone soil for revegetation of critical land. The research was conducted in a Completely Randomized Design with three replications. The treatments were P0 (Control, without ameliorant); P1 (Humic Acid, HA, 4 kg ha-1 ); P2 (Phosphate Rocks, PR, 350 kg ha-1 ); P3 (Vesicular Arbuscular Mycorrhizal Fungi, AMF, 500 spores plant-1 ); P4 (HA+AMF); P5 (PR+AMF); and P6 (HA+PR+AMF). Data were analyzed using ANOVA at 95% confidence level and continued with the LSD test. The use of various types of ameliorants (HA, RP, and AMF) significantly increased root length, root volume, wet and dry weight of roots, shoot wet and dry weight, and P uptake of gaharu tree. The best ameliorant in increasing gaharu tree growth was AMF (P3) treatment, and AMF combined with HA (P4) treatment. Thus, for revegetation of critical land, especially post-mining limestone land, using gaharu tree requires HA and AMF inoculation.

Application of Arbuscular Mycorrhizal Fungi and Soil Ameliorant on the Growth of Leucaena leucocephala in Limestone Post-mining Soil Media

Limestone mining has the potential into environmental damage that involve modify an ecosystem. The attempt that contrived to reduce the disturbances are rehabilitation. This research was conducted to examine the growth response of Leucaena leucocephala inoculated with AMF and soil ameliorant in a limestone post-mining soil. The design used was a split-plot design in a completely randomized design with 3 factors. The first factor was AMF inoculum (Daemonorops draco AMF and MycoSilvi), the second factor was organic fertilizer of compost, and the third factor was inorganic fertilizer. The variables used in this study expressed by height, diameter, biomass, root colonization, and nutrient absorption of the plant. The analysis showed that the combination of MycoSilvi and compost 7.5% gave best result of height, diameter, and biomass, with significantly increased by 962.67%, 899.41% and 1440.67% to control plant. It also gave best result of nutrient uptake N, P, and K, with significantly increased up to 17.64 g plant-1, 2.42 g plant-1, and 18.05 g plant-1. In general, AMF showed a good percentage of root colonization with an average 36.67-86.67%. Further research is needed to determine the response to the growth of seedlings planted in the field.

The linkage of 13C and 15N soil depth gradients with C:N and O:C stoichiometry reveals tree species effects on organic matter turnover in soil

The knowledge of tree species dependent turnover of soil organic matter (SOM) is limited, yet required to understand the carbon sequestration function of forest soil. We combined investigations of 13C and 15N and its relationship to elemental stoichiometry along soil depth gradients in 35-year old monocultural stands of Douglas fir (Pseudotsuga menziesii), black pine (Pinus nigra), European beech (Fagus sylvatica) and red oak (Quercus rubra) growing on a uniform post-mining soil. We investigated the natural abundance of 13C and 15N and the carbon:nitrogen (C:N) and oxygen:carbon (O:C) stoichiometry of litterfall and fine roots as well as SOM in the forest floor and mineral soil. Tree species had a significant effect on SOM δ13C and δ15N reflecting significantly different signatures of litterfall and root inputs. Throughout the soil profile, δ13C and δ15N were significantly related to the C:N and O:C ratio which indicates that isotope enrichment with soil depth is linked to the turnover of organic matter (OM). Significantly higher turnover of OM in soils under deciduous tree species depended to 46% on the quality of litterfall and root inputs (N content, C:N, O:C ratio), and the initial isotopic signatures of litterfall. Hence, SOM composition and turnover also depends on additional—presumably microbial driven—factors. The enrichment of 15N with soil depth was generally linked to 13C. In soils under pine, however, with limited N and C availability, the enrichment of 15N was decoupled from 13C. This suggests that transformation pathways depend on litter quality of tree species.

The Impact of Nickel Mining on Soil Properties and Growth of Two Fast-Growing Tropical Trees Species

Opencast nickel mining is common in natural forests of Indonesia. However, rehabilitation of postmining degraded land is difficult. We investigated the effect of opencast nickel mining on soil chemical properties and the growth of two fast-growing tropical tree species, Falcataria moluccana and Albizia saman. Soil was collected from post-nickel mining land and a nearby natural forest. Soil pH, available phosphorus (P) concentration, total carbon (TC) and total nitrogen (TN) concentration, C/N ratio, cation exchange capacity (CEC), and exchangeable K, Na, Mg, Ca, Fe, and Ni concentrations were determined. Falcataria moluccana and A. saman were then grown in the collected soils for 15 weeks in a greenhouse. Shoot height and shoot and root dry weights of the seedlings were measured. The post--nickel mining soils TN, TC, available P, CEC, and exchangeable Ca and Na concentrations decreased by 98%, 93%, 11%, 62%, 85%, and 74%, respectively, in comparison with the natural forest soils. The pH of postmining soil was higher than natural forest soil. Shoot dry weight of F. moluccana seedlings grown in postmining soil was significantly (P<0.05) lower than that of seedlings grown in natural forest soil. However, there was no difference in shoot dry weight between A. saman seedlings grown in natural forest soil and postmining soil, as well as root dry weights of both species. The results indicate that opencast nickel mining decreased soil fertility, which subsequently inhibited the growth of F. moluccana and A. saman seedlings.

Remediation of Soil Polluted with Cd in a Postmining Area Using Thiourea-Modified Biochar.

Cadmium presence in soil is considered a significant threat to human health. Biochar is recognized as an effective method to immobilize Cd ions in different soils. However, obtaining effective and viable biochar to remove elevated Cd from postmining soil remains a challenge. More modifiers need to be explored to improve biochar remediation capacity. In this investigation, pot experiments were conducted to study the effects of poplar-bark biochar (PBC600) and thiourea-modified poplar-bark biochar (TPBC600) on Cd speciation and availability, as well as on soil properties. Our results showed that the addition of biochar had a significant influence on soil properties. In the presence of TPBC600, the acid-soluble and reducible Cd fractions were transformed into oxidizable and residual Cd fractions. This process effectively reduced Cd bioavailability in the soil system. Compared to PBC600, TPBC600 was more effective in improving soil pH, electrical conductivity (EC), organic matter (SOM), total nitrogen (TN), ammonium nitrogen (), nitrate nitrogen (), available potassium (AK), available phosphorus (AP), and available sulfur (AS). However, this improvement diminished as incubation time increased. Results of Pearson correlation analysis, multivariate linear regression analysis, and principal component analysis showed that soil pH and available phosphorus played key roles in reducing the available cadmium in soil. Therefore, TPBC600 was shown to be an effective modifier that could be used in the remediation of soil polluted with Cd.

APLIKASI Desmodium ovalifolium YANG DIINOKULASI FUNGI MIKORIZA ARBUSKULA PADA BIBIT Octomeles sumatrana Miq. DI TANAH PASCA TAMBANG

Mining activities resulted on environmental degradation and ecosystem damage. Legume cover crop forming symbiosis with beneficial soil microorganism is widely well known to be used for degraded land reclamation such as in post mining area. Desmodium spp. is one of legume cover crop forming symbiosis with arbuscular mycorrhizal fungi (AMF) and rhizobium. This study aimed: (1) to isolate and characterize AMF collected from rhizosfer of 4 species of Desmodium spp. grow in gold mining of PT. Cibaliung Sumberdaya, Banten; (2) to study the growth of Octomeles sumatrana planted together with D . ovalifolium inoculated with AMF. Soil collected from post mining was used as growth media. There were two factors in this study: AMF inoculation and compost treatment s . Based on morphological characteristics after culture breeding , there were 23 spesies of Glomus sp. and 3 spesies of Acaulospora sp. isolated from 4 spesies of Desmodium spp. collected in PT. Cibaliung Sumberdaya. Inoculation of AMF and compost application increased height of O . sumatrana in two week s after planting. Single inoculation of AMF into O. sumatrana improved height and increased number of spore as well. Combination of compost with post mining soil had the highest increased in height, diameter, total biomass, roots biomass, and sprout biomass of O . sumatrana .

INFLUENCE OF ARBUSCULAR MYCORRHIZAL FUNGI AND SOIL AMELIORANTS ON THE MYCORRHIZAL COLONIZATION, CHLOROPHYLL CONTENT, AND PERFORMANCE GROWTH OF TWO TROPICAL TREE SEEDLINGS GROWN IN SOIL MEDIA WITH HIGH ALUMINUM CONTENT

Aluminum is one of heavy metals and its availability is correlated with low soil pH, such as in acidic soil as well as post mining soil and become limiting factors for plant growth. MycoSilvi is a biofertilizer inoculant product containing arbuscular mycorrhizal fungi enriched with Mycorrhizal Helper Bacteria’s (MHBs) designed for improving plant growth on post-mining soil media with low pH and high aluminum content. This study was conducted to determine the potential use of three variants of MycoSilvi, both single or in combination with soil ameliorant to enhance Albizia chinensis (Osbeck) Merrill and Pongamia pinnata (L.) Pierre growth. This study was conducted by randomized complete design with factorial scheme in a greenhouse for 4 months. The first factor consisted of four different levels based on MycoSilvi (M) inoculation: control (M0); MycoSilvi variant 1 (M1), MycoSilvi variant 2 (M2) and MycoSilvi variant 3 (M3). The second factor consisted of four levels based on the addition of lime and compost to soil medium: control (L0C0), addition of lime (L1C0), addition of compost (L0C1) and addition of lime and compost (L1C1). Data was analyzed using analysis of variance (ANOVA). Total chlorophyll content as indicated by leaf greenness index, height, steam diameter, biomass, root colonization and P accumulation on both plant species were observed after 12 weeks of planting. The results showed that the MycoSilvi inoculation differently colonized the roots and increased P uptake, leaf greenness index and growth of both plants species. The addition of lime and compost increased the mycorrhizal roots colonization, P uptake, leaf greenness index and plant growth of both plants’ species. The best result was obtained from the combination treatment of MycoSilvi variant 3, lime and compost

The arbuscular mycorrhizal fungus Rhizophagus intraradices and other microbial groups affect plant species in a copper-contaminated post-mining soil

Background and aimArbuscular mycorrhizal fungi (AMF) have an important role in plant-microbe interactions. But, there are few studies in which the combined effect of AMF with a stress factor, such as the presence of a metal, on plant species were assessed. This study investigated the effect of arbuscular mycorrhizal (AM) fungus Rhizophagus intraradices and other soil microbial groups in the presence of copper on three plant species in a microcosm experiment. MethodsTwo grass species Poa compressa and Festuca rubra and one herb species Centaurea jacea were selected as model plants in a pot-design test in which soils were artificially contaminated with copper. Treatments were bacteria (control), saprophytic fungi, protists, and a combined treatment of saprophytic fungi and protists, all in the presence or absence of the AM fungal species. After sixty days, plants were harvested and the biomass of grass and herb species and microbial respiration were measured. ResultsThe results showed almost equal above- and belowground plant biomass and microbial respiration in the treatments in the presence or absence of R. intraradices. The herb species C. jecea responded significantly to the soil inoculation with AM fungus, while grass species showed inconsistent patterns. Significant effect of AMF and copper and their interactions was observed on plant biomass when comparing contaminated vs. non-contaminated soils. ConclusionStrong effect of AMF on the biomass of herb species and slight changes in plant growth with the presence of this fungal species in copper-spiked test soils indicates the importance of mycorrhizal fungi compared to other soil microorganisms in our experimental microcosms.

Potential use of Claroideoglomus etunicatum to enrich signal grass (Brachiaria decumbens Stapf.) for silvopasture preparation

Silvopasture system improvement in managing post-mining land resources has been done by searching for a quality grass. One of the selected grass species is signal grass (Brachiaria decumbens Stapf.). This research aimed to prepare signal grass through the inoculation of AMF Claroideoglomus etunicatum, as an effort to enrich its growth before being applied to post-mining soil. Research stages included the AMF inoculation on signal grass through spore culture and then transferred the colonized grass to the pot using sterile zeolite as a growth medium. The treatment on the first stage was without and with AMF inoculation (dose of 20 spores) on signal grass which was repeated for 12 times. Incubation in a spore culture was 4 weeks while incubation in a pot containing sterile zeolite medium was 8 weeks. Research data were analyzed using the Shapiro-Wilk’s normality test, Independent Sample T-test, and Pearson’s correlation test. Observation results showed that the inoculation of C. etunicatum on signal grass was significantly impact on the increase of plant height, stem diameter, number of leaves, number of tillers, shoot and root fresh weight, and shoot dry weight (p <0.05). Microscopic observation showed that there was AMF colonization on treated signal grass roots in the amount of 55 ± 0.06 % with number of spores was 252 ± 9.82 per 10 g zeolites, while AMF infection was not found in uninoculated signal grass. It is expected that by providing signal grass inoculated with AMF C. etunicatum would support its growth in post-mining land for Silvopasture system.

Pengaruh Media Tanam Tanah Pasca Tambang dan Panjang Buku Terhadap Pertumbuhan Stek Tanaman Lada (Piper nigrum L.) Varietas Malonan I

The Effect of Post-Mining Soil Planting Media and Book Lengths on the Growth of Pepper Cutters (Piper nigrum L.) Varieties of Malonan I, Under the guidance of Mahdalena and Iin Arsensi. The purpose of this study was to determine the response of the growth of pepper cuttings (Piper nigrum L.) Malonan I variety using post-mining soil planting media. This research was carried out in Sungai Mariam Village, Anggana Subdistrict for 6 weeks from September to November 2018. The research was arranged in a Randomized Block Design (RBD) with Factorial experiments consisting of 2 factors with 3 replications. The first factor is the length of the book consists of two levels, namely s1 (length 3 books) and s2 (length 5 books). The second factor of the growing media consists of 3 levels, namely t1 (mining land), t2 (mining land and manure), and t3 (mining land and compost). The results showed that the treatment of post-mining soil planting media and the length of cuttings did not have a significant effect on all parameters, when growing shoots, number of shoots, and shoot length were 2, 4, 6 weeks after planting.

Effect of rockwool and lignite dust on physical state of rehabilitated post-mining soil

Anthropogenic impact on the environment causes worldwide problems such as land degradation and increase in waste production. In particular opencast lignite mining results in various environmental disturbances and rehabilitation of this land is necessary. For this purpose some wastes: post-production rockwool and lignite dust can be used. Little is known about the influence of these amendments on physical state of reclaimed soil after opencast lignite mine. The aim of this study was therefore to assess the impact of post-production rockwool and lignite dust on physical properties of a post-mine Technosol considering at the same time the possibility of reuse of these waste materials. Soil samples came from 4 fields after a lignite mine: (1) control; (2) and (3) application of 200 or 400 m3 ha–1 post-production rockwool; (4) application of 1000 Mg ha–1 lignite dust. To achieve our objective we evaluated: gravitational water (GW), water available (AW) and unavailable (UW) for plants, air permeability (AP), saturated hydraulic conductivity (KS), soil water characteristic curves, unsaturated hydraulic conductivity function, pore-size distributions, texture, particle and bulk density, total porosity, TOC, pH, and soil structure. The application of post-production rockwool or lignite dust modified some physical parameters of the studied soil. The soil bulk density decreased to the largest extent resulting in the increase of the total porosity. The soil properties important for plant condition (AW, GW, KS and AP) were favourable. The study showed that the greenhouse post-production rockwool and the lignite dust can be utilized for the reclamation of post-mining soils, what will reduce at the same time their storage in landfills.

Nitrogen fertilization and its legacy have inconsistent and often negative effect on plant growth in undeveloped post mining soils

Nitrogen supplement by adding N-fertilizer and/or growing of N-fixing trees are considered as important stimulus for the development of early vegetation. We performed pot experiments to determine the responses of legumes (N-fixing) and grasses (non-N fixing) in respect to their biomass to N fertilization, legacy of N, and combination of these two in various ages of post mining soils. N legacy was achieved either by long-term mineral N fertilization (legacy of inorganic N) (experiment 1) or growing of N2 fixing plant (legacy of N-fixing) (experiment 2). The first pot experiment was conducted to test N fertilization and legacy of inorganic N and these two on growth of Festuca rubra and Lotus corniculatus when grown separately. Following this, plant-soil feedback was defined as positive or negative by comparing the second generation of plant biomass in soils with and without plants in the previous generation. In the second pot experiment, we compared the performance of P. compressa and L. corniculatus in the presence of legacy of N-fixing and N fertiliaztion when grown together, and at the same time, plant-soil feedback was determined.N fertilization increased the growth of grasses, but only increased biomass of legumes in young soils. N-legacy induced variable plant growth, in particular often decreased the biomass of legumes. Legacy of inorganic N was only beneficial for grasses rather than legumes in medium soils. When growing in the same pot, legacy of N-fixing showed positive effects on grasses, depending on soil age and N fertilization. Repeated growing of plants in the same soil mostly resulted in negative plant-soil feedback. Negative plant-soil feedback was not alleviated by N fertilization and legacy of inorganic N for both grasses and legumes when grown separately. However, growing grasses and legumes together can induce positive plant-soil feedback with no legacy of N-fixing.In conclusion, N addition often stimulates plant growth more than long-term N effect. Legacy of N tends to be only beneficial for non-N fixing plants in medium aged soils. While negative plant-soil feedback occurs for grasses and legumes both grown separately or together, legumes can induce positive plant-soil feedback when grown with grasses in no legacy of N-fixing soils.

Draft Genome Sequence of Enterobacter sp. Strain AD2-3, Isolated from a Postmining Site in Benguet, Philippines

The novel strain Enterobacter sp. strain AD2-3 was isolated from postmining soil samples collected from Antamok mine in Benguet, Philippines. Here, we report a draft of its whole-genome sequence, with predicted gene inventories supporting metal tolerance, nitrogen fixation, phosphate solubilization, and indole acetic acid production.

The effect of arbuscular mycorrhizal fungi Rhizophagus intraradices and soil microbial community on a model plant community in a post-mining soil

The aim of this study was to assess the effect of arbuscular mycorrhizal fungi Rhizophagus intraradices and soil microbial groups and their interactions on a simple plant community in a microcosm experiment. The experiment was performed with two grass species (Poa compressa, Festuca rubra) and two herb species (Centaurea jacea, Lotus corniculatus) which are characteristic of intermediate succession stages in post-mining sites. Three months before the start of the experiment, bacteria, saprophytic fungi, protists, and their combined treatments were inoculated into the soil. At the start of the experiment, half of the pots were inoculated with mycorrhiza. After 60 days, plants were harvested and shoot and root biomass and microbial respiration and biomass were assessed. Above- and belowground plant biomass was significantly lower in the treatments with mycorrhiza. The effect was significant for aboveground biomass of grasses, especially that of Poa compressa, and for grass/herb ratio but not for herbs. Microbial respiration was also lower with mycorrhiza. Among microbial community treatments, saprophytic fungi showed significant effects on plant growth. The results showed the importance of mycorrhizal fungi on plant biomass and its interaction with different plant species and microbial groups which would be useful when extrapolating these results to a natural environment.

Nickel (Ni) reduction in Sorowako post-mining soil through application of mycorrhiza Acaulospora sp. associated with Canavalia ensiformis L.

The nickel (Ni) content in a post-mining soil of Pomalaa mines reached 14,200 mg.kg-1 and became a limiting factor in the plant growth process. A Ni reduction in the soil by using phyto-accumulator such as Jack bean (Canavalia ensiformis L.) can be improved by combining it with arbuscular mycorrhizal (AM) fungi. The purpose of this study was to determine the effect of the mycorrhizal fungus Acaulospora sp. on the efficiency of Ni reduction by C. ensiformis. This experiment was carried out by using a randomized block design with three different treatments, include: 1) C. ensiformis without Acaulospora sp. inoculation (negative control), 2) C. ensiformis inoculated with indigenous Acaulospora sp. and 3) C. ensiformis inoculated with non-indigenous Acaulospora sp. The study was conducted in the nursery that belongs to PT. Vale Indonesia Tbk., Sorowako, South Sulawesi, Indonesia. The results showed that highest nickel accumulation was found in the root inoculated with indigenous Acaulospora sp. (9500 mg.kg-1), followed by stem (1400 mg.kg-1), leaf and pod (1300 mg.kg-1), seed (1200 mg.kg-1), and flower (1100 mg.kg-1). This study indicates that application of the indigenous Acaulospora sp. can improve C. ensiformis efficiency to reduce Ni content at Sorowako post-mining area.

Dung beetle activity improves herbaceous plant growth and soil properties on confinements simulating reclaimed mined land in South Africa

Mining activities contribute greatly to economic growth and development in South Africa. However, post-mining soils have limited land-use potential due to low fertility, deficiency in organic matter content and poor physical, chemical, and microbiological properties. Dung beetles could potentially improve several aspects of soil degradation, complementing current rehabilitation efforts. Studies in relatively undisturbed soils of agro-ecosystems have found that dung burial introduces essential nutrients in dung to the plant root zone, which would otherwise remain on the soil surface and mostly volatilize in the absence of dung beetles. Furthermore, dung beetles create tunnels under dung pats, improving water infiltration rates, bulk density, soil aeration and pasture yields. The aim of the study was to determine whether these effects could be maintained on soil simulating reclaimed mined land, where very high rates of compaction may prevent tunnelling altogether. Three experimental treatments of dung + beetles (D + B), dung only (D) and control/no dung, no dung beetles (X) were applied twice over 2 years on 1 m3 experimental confinements. Various soil and herbaceous plant properties were assessed one and six months after each application of dung and beetles. Results obtained showed that water infiltration rate and plant biomass was significantly higher for all confinements containing dung beetles. Penetration resistance (soil strength) was significantly reduced for confinements with dung beetles. Magnesium and potassium levels in the soil were significantly higher for D + B treatments when compared to D and X treatments. In conclusion, results showed that dung beetles were able to maintain their activities in soils typical of reclaimed mine land, significantly improving soil properties and herbaceous plant growth. Incorporating the application of dung beetles to the conventional approach to rehabilitation has the potential to improve the efficacy of coal mine reclamation. This biological approach may also prove to be cost-effective over time as it provides a seasonal source of bioturbation, which does not disturb plant growth and reduces the requirements for soil rejuvenating tillage practices.