The impact of cow dung augmentation on soil restoration and bio-accumulation of metals (Lead and Cadmium) in Pheretima posthuma (Annelida: Clitellata)

To investigate the role of cow dung in soil reclamation and bio assimilation along with bio accumulation of heavy metals in earthworm (P. posthuma) (N=900) earthworms were used and treatment groups of CD-soil mixture of different proportion of cow dung were designed. Nonlethal doses of lead acetate and cadmium chloride were added in treatment groups. Mature P. posthuma were released in each experimental pot maintaining the favorable conditions. The pH, carbon, nitrogen, phosphorus, exchangeable cations, and heavy metal level of each mixture was evaluated. The results indicated that bio-assimilation of Pb and Cd by P. posthuma were significantly (P ˂ 0.01) higher in different soil-CD treatments compared to control. Highest bio-assimilation of both metals was observed in T1 of both groups (Pb = 563.8 mg/kg and Cd = 42.95 mg/kg). The contents of both metals were significantly (P ˂ 0.05) lowered in casting. The nutrient concentration in the final castings of all soil-CD treatments were also equally transformed from less or insoluble to more soluble and available for plants, except for carbon level which increased with CD proportion. It is concluded that cow dung as organic matter has a positive effect on soil reclamation and bio-assimilation of metals by P. posthuma.

Effects of Inorganic, Organic and Bio-Organic Fertilizer on Growth, Rhizosphere Soil Microflora and Soil Function Sustainability in Chrysanthemum Monoculture

The production of chrysanthemums is severely hampered by Fusarium wilt, which is exacerbated by monoculture. In this study, the role of inorganic plant nutrition fertilizer (IPN), organic fertilizer (OF) and bio-organic fertilizer (BOF) in avoiding monoculture-related production constraints was evaluated. We conducted a series of greenhouse experiments and studied the growth of chrysanthemum and changes in rhizosphere soil microflora and function. BOF application reduced the incidence of Fusarium wilt by 82.8% and increased the chrysanthemum shoot height and flower ray floret number by 31.4% and 26.1%, respectively. High-throughput Illumina HiSeq2500 sequencing results indicated that BOF and OF treatments increased the values of α-diversity indices of bacteria and fungi. In addition, significant alterations in microbe community structures were found in response to IPN, OF or BOF application. Among the major genera detected after BOF treatments, the levels of Fusarium and Glycomyces decreased while Cladosporium, arbuscular mycorrhizal and endophyte groups increased. In particular, the abundance of Mariniflexile had a positive relationship (R = 0.693, p < 0.05) with the incidence of Fusarium wilt, while Cladosporium showed a significant negative relationship (R = −0.586, p < 0.05). Interestingly, an analysis of microbiomes based on 16S rRNA sequences revealed that the functions of signal transduction, bacterial secretion system, oxidative phosphorylation and the metabolism of carbohydrate, nitrogen and amino acids all increased in both BOF and OF treatments. The results suggested that BOF could be effective for chrysanthemum monoculture soil restoration, potentially by altering the microbial community structures and functions, which affect the physiological and morphological attributes of chrysanthemum in monoculture.

Restoring the Soils of Nauru: Plants as Tools for Ecological Recovery

<p>The restoration of Nauru’s mined areas is fundamental to the future wellbeing of the people and ecosystems of Nauru. Extensive open cast phosphate mining on Nauru over the last 100 years has led to soil losses and landscape degradation to the extent that over 70% of this South-Western Pacific island state is now uninhabitable and almost all productive land has been lost. Significant landscape degradation has occurred and as a consequence the soils that remain are insufficient in volume and quality to achieve the Government’s restoration goals which support the long-term development of Nauru and the well-being of its people. The aim of this research is to evaluate aspects of cover-crop use as a means for soil restoration in Nauru. This research evaluates biomass production, phytoremediation potential, and germination success for a range of species in Nauruan soils. Field trials exploring biomass production and cadmium phytoextraction were performed, as was an experiment assessing the effects of cadmium on germination success. It was found that, in the circumstances assessed, biomass productivity was significantly determined by species, mulch use, soil type, and to a small degree – cadmium. Phytoextraction was significantly determined by tissue type. Germination success was not determined by soil cadmium, but soil type was a significant factor.</p>

Restoring the Soils of Nauru: Plants as Tools for Ecological Recovery

<p>The restoration of Nauru’s mined areas is fundamental to the future wellbeing of the people and ecosystems of Nauru. Extensive open cast phosphate mining on Nauru over the last 100 years has led to soil losses and landscape degradation to the extent that over 70% of this South-Western Pacific island state is now uninhabitable and almost all productive land has been lost. Significant landscape degradation has occurred and as a consequence the soils that remain are insufficient in volume and quality to achieve the Government’s restoration goals which support the long-term development of Nauru and the well-being of its people. The aim of this research is to evaluate aspects of cover-crop use as a means for soil restoration in Nauru. This research evaluates biomass production, phytoremediation potential, and germination success for a range of species in Nauruan soils. Field trials exploring biomass production and cadmium phytoextraction were performed, as was an experiment assessing the effects of cadmium on germination success. It was found that, in the circumstances assessed, biomass productivity was significantly determined by species, mulch use, soil type, and to a small degree – cadmium. Phytoextraction was significantly determined by tissue type. Germination success was not determined by soil cadmium, but soil type was a significant factor.</p>

Soil Restoration Practices Effects on Priming Effect Intensity and Carbon Fluxes

BackgroundThe decomposition of soil organic matter (SOM) is one of the most important processes influencing the global carbon (C) cycle, the physico-chemical characteristics of soils, the mineralization of nutrients for plant growth and soil food webs. Yet, priming effects are considered to be large enough to influence ecosystem carbon fluxes. Here we have tested the effects of soil restoration practices on priming effect and carbon fluxes.ResultOur results suggest that indirect effects are such as altered stabilization of older C associated with the increased inputs of fresh plant inputs (‘priming’) add uncertainty to the prediction of future soil C responses. Far ahead restoration influence the amount and composition of the decomposer organisms, including soil fauna, as well as the soil microbial community, by inducing up to more CO2 emission with fresh millet straw addition in fresh state than pre-decomposed one. Restoration had a very strong impact (increase by 22.7%) on basal soil organic matter mineralization but not on priming effect. The PE of non-restored site was lower than that of restored site by 14.9–22.7%; the lowest mineralization per unit carbon was recorded in the non-restored. Through the “4 per 1000” initiative, it has been very recently demonstrated that priming effect could have a noticeable impact on soil carbon sequestration. ConclusionWe have shown in our study that the degraded soil played a dominant positive role in the soil organic carbon mineralization. Our results provide solid evidence that SOC content plays a critical role in regulating apparent priming effects, with important implications for the improvement of C cycling models under global change scenarios.

Pyrogenic impact on biology activity of chernozem in model experiments

The influence of the pyrogenic effect on the biological properties of Haplic chernozem was investigated. For this, a series of model experiments was set up to simulate fires of various duration and intensity. A significant change in the biological properties of soils was found, as well as differences in the reactions of biological indicators to the pyrogenic effect. In different experiments, a different nature of changes in the reaction of the soil environment and the content of organic carbon, an increase in the content of readily soluble salts, was established. In all experiments, inhibition of catalase activity was noted, changes in peroxidase activity were more contradictory. In one of the experiments, stimulation of peroxidase activity was found. In order to study the methods of restoring the biological activity of post-pyrogenic soils, a model experiment was carried out using potassium humate, complex mineral fertilizer and phytoremediation. At the same time, no unambiguous results were obtained that would make it possible to recommend methods for the accelerated recovery of post-pyrogenic soils. Keywords: BIODIAGNOSTICS, FIRES, POSTPYROGENIC SOILS, ENZYME ACTIVITY, SOIL RESTORATION

Insight into the Characteristics of Soil Microbial Diversity during the Ecological Restoration of Mines: A Case Study in Dabaoshan Mining Area, China

Soil microorganisms play an important role in regulating a variety of ecological functions. In recent years, the research on ecological restoration after mining has made people more aware of the importance of microbial diversity to ecosystem restoration. The present study investigated the effect of ecological restoration on microbial community structure and its relationship with soil physicochemical properties in the Dabaoshan mining area, China. High throughput sequencing technology was used to analyze and compare the microbial community composition of three types of soil (undamaged area, unrestoration area, and ecological restoration area). The contents of organic carbon, total nitrogen, and total phosphorus were 2.38–12.97 g/kg, 0.39–1.62 g/kg, and 0.99–1.51 g/kg, respectively. In different soil states, undamaged area and ecological restoration area were significantly higher than those in unrestoration area. The results showed that the structure of soil microbial community was significantly correlated with soil physicochemical properties, and formations in the repaired and unrepaired soils were different. Operational Taxonomic Unit (OTU) cluster analysis and diversity index analysis showed that soil microbial community changed at phylum and genus levels. The results showed that at the phylum level, all soil samples contained Firmicutes, Proteobacteria, and actinobacteria. Firmicutes and Proteobacteria of the ecological restoration area (ER1, ER2) were the highest in relative abundance compared with other samples, accounting for more than 45%. Proteobacteria and Acidobacteria were the dominant phylum in the undamaged area (UD), accounting for 32.7% and 22.3%, respectively. It can be seen that soil restoration produced a new dominant population, and Proteobacteria showed an absolute competitive advantage in the mining soil.

BIOTECHNOLOGICAL METHODS OF PROCESSING FOREST COMPLEX WASTE

The intensive development of agriculture in the Voronezh Region has led to serious negative changes in the soil condition. There was a decrease in the content of humus and mineral substances. More than 350 thousand hectares of the region’s soils have a low content of humus and, as a result, organic matter (s) available for decomposition. Among the methods of soil restoration, soil improvers are gaining popularity. These are, as a rule, compost, various organic fillers, bio-coal. The latter are considered promising meliorants of natural origin. The processing of waste from the timber industry and sewage sludge into bio-coal is proposed. Its influence on the water permeability of leached chernozem is studied. The positive effect of biochar on the filtration properties of the soil has been established. The filtration rate after applying the biochar increased by 2.5-4 times compared to the control. The maximum water permeability was observed at a biochar concentration of 20 -30% to the soil mass. It is established that the amount of moisture that has passed through the soil depends on the dose of the introduced biochar. The addition of biochar in the amount of 5, 10, 20 and 30% led to a significant increase in the filtration qualities of the soil, compared with the control. The tendency of the ability of biochar to improve the water-physical properties of the soil is revealed.

Soil Restoration through the Application of Organic Mulch Following Skidding Operations Causing Vehicle Induced Compaction in the Hyrcanian Forests, Northern Iran

In this study an attempt was made to assess how different mulches affect the soil environment. In particular, different organic mulches such as leaf litter, straw and sawdust were tested in order to assess their capacities to amend the soil conditions. These analyses were carried out in the Hyrcanian mixed broadleaved forest. Organic mulches can compensate the litter layer loss on compaction-induced soil and accelerate the restoration process of soil properties, which takes from a few years to several decades without mulching. However, comprehensive knowledge on the effects of organic mulch on soil quality in terms of compaction-induced soil in the scientific literature is still scarce and inadequate. The main aim of the study was to examine the effects of three organic mulches (leaf litter, straw and sawdust) on the restoration of forestry vehicle-induced soil properties in the skid trail over a 2-year period. The results showed as the values of soil physical and chemical properties in litter, straw and sawdust treatments were significantly restored as compared with the values in the untreated soil. In general, leaf litter supplies nutrients at higher rates than the straw and sawdust mulches. However, according to the current results, a 2-year period is not enough to return the soil physical and chemical properties to pre-traffic levels. Furthermore, the present study shows that organic mulch spread on the surface of mineral soil in the skid trails after machine traffic acts as a fertilizer to accelerate the decomposition of organic matter.