Restore Soil Quality Research Articles

Economic and legal mechanisms for effective use of land resources under the conditions of sustainable development in Ukraine

Sustainable society development distinctly entails the issues of sustainable use of land and especially soils, which are the place and condition of human activity, the means of production that provide absolute value, and a unique natural resource. Ukraine possesses nine percent of the world’s black soil (chernozem) resources, which necessitates the development of sufficient economic and legal mechanisms for their effective use in ensuring food security within the country and worldwide, increasing the export potential of Ukraine subject to the soil quality restoration, and determines the scope of this work. The land reform in Ukraine as a component of economic reform has led to a significant deterioration of agricultural land, loss of humus from soils, their degradation, and other negative consequences threatening the country’s economic security and generating socio-economic and demographic crisis phenomena, especially in rural areas. Therefore, the study has identified priorities and has proposed the use of contractual mechanisms in the field of sustainable socio-economic use of land resources. The authors applied an integrated approach to the analysis of sustainable land use issues to achieve the study objective. This led to the use of a wide range of methodological tools, in particular, the dialectical method, the formal logical method, the logical legal method and the methods of analysis, synthesis and comparison. Defined provisions that determine the economic and legal mechanism of land use and should be ensured in the process of sustainable development: meeting the needs of landowners and other persons, including the priority needs – environmental and food security; an increase in the area of land not involved in the economic turnover, the adoption of measures aimed at the preservation and restoration of agricultural land, in particular compliance with the requirements for crop rotation, and, in some cases, their conservation; introduction of contractual relations in the field of land use.

Salinity Management in Pima Cotton Fields Using Sulfur Burner

Core Ideas Salinity and sodicity in irrigated cotton fields are reducing soil productivity, lint yield, and fiber quality in arid and semiarid regions of the world. Sulfur burner treatment of irrigation water can be used to tap native CaCO3 to produce CaSO4 in a safe manner. Calcium sulfate increases Ca availability in the root zone to counter Na, improve soil permeability, and leach salts to deeper depths. Salinity and sodicity are the dual problems affecting soil productivity, lint yield, and fiber quality in the irrigated pima cotton (Gossypium hirsutum L.) fields in far west Texas. This field study evaluated the effects of S burner‐treated blended irrigation water on sodicity and salinity of the root zone, cotton lint yield, and fiber quality. Results indicated that pre‐study soil salinity and sodicity exceeded the threshold levels in many areas within the 9.2‐ha study site. One year of irrigation with S burner‐treated water resulted in 19% reduction in salinity of the upper 0‐ to 30‐cm depth and redistribution of salts at deeper depths. Average sodium adsorption ratio (SAR) of study site soils decreased by 3 to 5% at 0‐ to 15‐, 30‐ to 45‐, and 45‐ to 60‐cm depths and reduction in the SAR range for 15‐ to 30‐ and 60‐ to 75‐cm depths indicated redistribution of Na. Irrigation with S burner‐treated blended water increased annual cotton lint yield by 20% compared with long‐term average and improved fiber quality. However, 1 yr of irrigation with S burner‐treated water did not reduce the maximum soil ECe and SAR values below the threshold levels at different depths. Multi‐year studies are needed to confirm our results and quantify the duration required to restore soil quality, cotton yield, and fiber quality.

Bounded set of economic uncertainty and robust viability: An illustration from farming systems

AbstractUncertainty occupies a major place in the literature, both when it is being defined and when it is being measured. The mathematical viability theory framework provides useful concepts to go beyond the probabilistic views of uncertainty that are not able to capture all forms of uncertainty, particularly in the absence of statistical regularities. Bounded‐set uncertainty can help to analyze changes in the evolutionary conditions that affect ecological and social systems with probabilistic or nonprobabilistic distributions. This paper introduces uncertainty into a viability model by associating stochastic and bounded‐set uncertainty related to sales price as a driver of economic uncertainty. Based on an illustration of agroecosystems, the model identifies decision rules that guarantee viability. The larger the initial crop portfolio for sequential diversification is, the lower the costs to belong to the viability kernels will be, regardless of economic and environmental constraints. The diversification of farming systems transforms their complexity into an advantage against uncertainty, which opens up numerous viability trajectories.Recommedations for Resource Managers Considering the relevance of a bounded set of economic uncertainty, restoring soil quality and choosing diversification guarantee viability and allow a single generation of farmers to relax both their environmental and economic constraints. When the time available to conform to both their environmental and economic constraints decreases, sequential diversification can be used as a tool to relax the economic constraint of self‐financing soil restoration. Sequential diversification is an asset, especially for low‐quality soil. Even under uncertainty and very low soil quality, diversification drastically reduces the value‐at‐risk for viable farming investment. Eligibility for agricultural subsidies should be conditional on soil quality to motivate practices of soil restoration that provide a sort of insurance against economic uncertainty.

Different efficiencies of the same mechanisms result in distinct Cd tolerance within Rhizobium

Soil contamination with metals is a widespread problem posing risks to humans and ecosystems. Metal contaminated soils often hold poor microbial density and biodiversity. Among soil bacteria, rhizobia have a great agronomic and environmental significance and are major contributors to a sustainable maintenance of soil fertility. This group of microorganisms are severely affected by metals, such as cadmium (Cd), but information about metal resistance mechanisms in rhizobia is still limited. A concerted approach of the different mechanisms conferring Cd tolerance to rhizobia was conducted using two Rhizobium strains with contrasting tolerances to Cd. Results show that both strains resort to the same mechanisms (extracellular immobilization, periplasmic allocation, cytoplasmic sequestration and biotransformation of toxic products) to overcome stress, but differences in the efficiencies of some mechanisms were noticed. The ability of Rhizobium to increase glutathione in the presence of Cd emerges as a central factor in the tolerance to Cd and is as a feature to be looked for when screening or transforming microorganisms to integrate plant-microbe consortia. These could promote plant growth at contaminated sites, being more efficient for the cleanup of metals from contaminated sites and the restoration of soil quality.

Phosphorus dynamics and solubilizing microorganisms in acid soils under different land uses of Lesser Himalayas of India

Although chemical and some soil physical properties have been studied under different land uses of the Lesser Himalayas of India, very limited information is available on soil biochemical properties. Hence we investigated phosphorus (P) fractions [total P (TP), inorganic P (Pi), organic P (Po), available P, microbial biomass P (MBP)], enzyme activities [dehydrogenase, phosphatases, phytase], phosphate solubilizing bacteria (PSB) and fungi (PSF), and their correlations of acid soils (0–15 and 15–30 cm depths) under different land uses (viz, organic farming, maize–wheat, apple orchard, undisturbed oak forest and uncultivated land of the Indian Himalayas). All land use systems differed significantly for the P fractions, except TP. The highest values for TP, Pi, available P and MBP were found in soils under oak forest and lowest in uncultivated land. However, Po content was highest in apple orchard. The organic farming (organic manures field under garden pea-french bean cropping system for > 10 years) maintained highest activities of dehydrogenase, acid phosphatase and alkaline phosphatase. The highest phytase activity and highest numbers of PSB (99 × 103 g−1 soil) and PSF (30 × 103 g−1 soil) were observed in the rhizosphere soils of oak forest. Significant relationships between soil P fractions and enzyme activities, except alkaline phosphatase, were recorded in surface soil layer. PSB and PSF population were also correlated significantly with P fractions and enzyme activities. This would lead us to understand the level of degradation of P pools due to cultivation over forest system and the suitable management practices needed for soil quality restoration.

Assessment of hydrocarbon degradation potentials in a plant–microbe interaction system with oil sludge contamination: A sustainable solution

ABSTRACTA pot culture experiment was conducted for 90 days for the evaluation of oil and total petroleum hydrocarbon (TPH) degradation in vegetated and non-vegetated treatments of real-field oil-sludge-contaminated soil. Five different treatments include (T1) control, 2% oil-sludge-contaminated soil; (T2), augmentation of microbial consortium; (T3), Vertiveria zizanioides; (T4), bio-augmentation along with V. zizanioides; and (T5), bio-augmentation with V. zizanioides and bulking agent. During the study, oil reduction, TPH, and degradation of its fractions were determined. Physico-chemical and microbiological parameters of soil were also monitored simultaneously. At the end of the experimental period, oil content (85%) was reduced maximally in bio-augmented rhizospheric treatments (T4 and T5) as compared to control (27%). TPH reduction was observed to be 88 and 89% in bio-augmented rhizospheric soil (T4 and T5 treatments), whereas in non-rhizospheric and control (T2 and T1), TPH reduction was 78 and 37%, respectively. Degradation of aromatic fraction after 90 days in bio-augmented rhizosphere of treatments T4 and T5 was found to 91 and 92%, respectively. In microbial (T2) and Vertiveria treatments (T3), degradation of aromatic fraction was 83 and 68%, respectively. A threefold increase in soil dehydrogenase activity and noticeable changes in organic carbon content and water-holding capacity were also observed which indicated maximum degradation of oil and its fractions in combined treatment of plants and microbes. It is concluded that the plant–microbe soil system helps to restore soil quality and can be used as an effective tool for the remediation of oil-sludge-contaminated sites.

Impact of brackishwater shrimp farming at the interface of rice growing areas and the prospects for improvement in coastal India

The coastal plain of Odisha in the northeastern region of India is designated the “rice bowl” of the state and is vulnerable to the impact of brackishwater shrimp farming, a prominent livelihood in southeastern Asia. Shrimp farming is highly profitable. However, owing to plentiful resources, shrimp farming has encroached on several rice-growing areas and a decline in the quality of natural resources in the coastal neighborhood has since been reported. This paper aims to study the effects of the unplanned expansion of brackishwater shrimp farming on natural resources and to provide a pathway to suitable utilization in order to improve the livelihood security of marginal shrimp farming communities in coastal Odisha, India. The practice of brackishwater shrimp farming has been determined to induce salt stress at 341–9387 ppt ha−1 crop−1 with a soil EC ranging from 0.3 to 3.4 and 0.5 to 9.5 dSm−1 under the Scientific Extensive Traditional (SET) method and 0.1 to 1.4 and 0.2 to 3.6 dSm−1 under the Traditional/Improved Traditional (IT) practice during post– and pre–farming periods, respectively. Soil with ≥35% clay content underwent a severe loss of saturated hydraulic conductivity (Ks), and soil with a low exchangeable sodium percentage (6.09–8.03%) showed more susceptibility towards Na saturation than did soil with a high exchangeable sodium percentage (>10%) after brackishwater shrimp farming. Growing salt-tolerant rice in shrimp ponds during non–farming periods was observed to reduce soil Ks by only 1.2–1.3-fold compared to a reduction of 22–40-fold under shrimp farming. The paper concludes that by promoting salt washing and alleviating salinity hazards, the shrimp–rice sequence has shown promise to restore soil quality, reduce vulnerability, enhance resilience in brackishwater shrimp farming where the farms interface with rice-growing coastal areas, and provide support to conserve the coastal environment.

Impact of an integrated no-till soybean–beef cattle production system on Oxisol mineralogy in southern Brazil

Agricultural activities in the state of Rio Grande do Sul (RS), southern Brazil, have traditionally been quite intensive and led to decreased overall soil quality, and to depletion of soil organic matter and nutrients. There have been attempts at restoring soil quality by using integrated crop–livestock systems (ICLS). ICLS in association with no-tillage (NT) potentially increase soil organic matter content and nutrient supplies. The aim of this work was to assess the influence of grazing intensity in three different treatments [viz., intensive grazing (IG), moderate grazing (MG) and no grazing (NG)] on the mineralogy of an Oxisol in an integrated soybean–cattle beef production system in southern Brazil by using various types of methods and tests. Mineralogical XRD analyses of the clay fraction (<2μm) showed it to consist mainly of kaolinite and 2:1 clay minerals of the hydroxy-interlayered mineral (HIM) type. The reflections for 2:1 clay minerals under the IG treatment were better defined than those for the minerals under NG, which suggests the prevalence of HIMs. The 2:1 clay minerals in the IG group exhibited expandable layers. Splitting the clay fraction into three subfractions according to size (<0.05μm, 0.05–0.1μm and 0.1–2μm) exposed considerable alterations. Thus, hydroxy-aluminum interlayered vermiculite (HIV-Al) was present irrespective of treatment. Also, the HIV-Al reflection was better defined under IG and MG than under NG, which suggests strong aluminization of 2:1 clay minerals. Chemical analyses revealed a decrease in total organic carbon (TOC) with increasing depth in all treatments. The decrease was especially marked under NG by effect of the absence of animals favoring accumulation of plant shoots. pHwater was higher under IG as a result of the removal of aluminum from the soil solution increased aluminization of 2:1 clay minerals. K concentrations in solution were low under IG as a result of the formation of HIMs and/or swelling layers with exchangeable K; by contrast, solution K levels under NG where high owing to the absence of HIMs. The presence of animals, which increases K availability through animal wastes, may have resulted in competition between exchangeable K+ and Al3+ to form HIMs. Without splitting the clay fraction it would have been impossible to confirm the mineralogical alteration in 2:1 phyllosilicates due to the impact of ICLS systems.

Evaluation of Soil Erosion and Sustainable Land Use Management in the Sarısu Basin

Land use management requires controlling natural resources for sustainability. Soil erosion related to improper land use is a major issue around the world. Land degradation may harm the health of ecosystems. Defining the soil loss in a basin is the starting point in the restoration of soil quality for crop production. Reducing soil losses to a tolerable rate is one of the primary objectives for sustainability and soil conservation. Central Anatolia is under considerable risk due to an increase in the cultivation of marginal lands for food production. Cultivated lands have already been reached the final limits throughout the last 50 years. Moreover, forests and considerable areas of pasture have recently been converted to ploughed fields due to agricultural expansion. This study was conducted in the Sarısu basin to evaluate soil losses and land use management for sustainability. The Universal Soil Loss Equation model and Geographic Information System techniques were used to estimate the soil losses. The mean potential soil loss of the basin was calculated to be 1.88 t ha-1 per year with the Universal Soil Loss Equation model. These results are comparatively small when compared to the average value for Turkey of 13 t ha-1 yearly. Our calculated results are closer to the value for the Sakarya river basin, which is approximately 2.77 t ha-1 y-1. In this study, land usages in the Sarısu basin were evaluated in terms of soil losses, tolerable soil loss rates and soil conservation precautions.

Agroecological transition: A viability model to assess soil restoration

AbstractSince the 1950s, intensive and specialized agricultural systems using a few select species and relying heavily on agrochemical inputs have enabled a huge increase in food production. However, in parallel, drawbacks appeared including biodiversity loss, greenhouse gas emission, erosion, and water pollution. Today shifting farming systems to mitigate soil degradation trends is indispensable. Using viability theory, we propose a dynamic model of the sequence of agricultural productions and practices that can be implemented in the long term to restore soil quality while respecting a set of agronomic and economic constraints. The paths to soil restoration vary depending on agronomic and economic constraints, the time available for restoration, the initial soil conditions, and investment capacities. Economic valuation of the minimum cost of restoration shows that the agroecological transition may be costly and that farmers can have difficulty meeting the costs, thus raising the question of how the cost of agroecological transition is to be shared.

Various effects of land tenure on soil biochemical parameters under organic and conventional farming − Implications for soil quality restoration

Land tenure insecurity is one of the worldwide problems that often leads to soil degradation. We tested whether owner-operators maintain a higher level of soil quality and biochemical activity than tenant-operators and how this effect is modified by the agricultural system (organic vs. conventional) in arable fields. We selected 45 plots with cambisol soil based on a factorial design of owner-operator vs. tenant-operator and organic vs. conventional management. On all tested plots, the crop was wheat in shortly after harvest. We measured total carbon in soil and a set of 8 soil enzymes: acid phosphatase, β-glucosidase, α-glucosidase, cellobiohydrolase, β-xylosidase, chitinase, glucuronidase and arylsulfatase. These enzymes participate in the main geochemical nutrient cycles in soils.Differences in the activity of 4 out of these 8 enzymes and differences in the weighted means of the total enzyme activity show a joint effect and indicated higher biochemical activity of the soil under conventional farming in plots farmed by owners. However, when organic farming was practiced, no obvious differences in enzymatic activity were found between soils farmed by owners or by tenants. The total carbon showed a similar pattern, although not significant. Generally, we conclude that farmer’s motivation for making investments in soil health is driven by tenure security, especially in cases where the farm economy depends on profit from crop yields. However, the positive features of tenure security can also be ensured by effective agroecological standards, strict rules, higher levels of subsidies and other incentives that are typically provided for organic farming. We propose that changes in agricultural policies may not only stop land degradation in various parts of the world but also support ecosystem restoration process.

Application of drum compost and vermicompost to improve soil health, growth, and yield parameters for tomato and cabbage plants

Utilization of different types of solid wastes through composting is important for environmental sustainability and restoring soil quality. Although drum composting is an efficient technology, the possibility of heavy metal contamination restricts its large-scale use. In this research, a field experiment was conducted to evaluate the impact of water hyacinth drum compost (DC) and traditional vermicompost (VC) on soil quality and crop growth in an agro-ecosystem cultivated intensively with tomato and cabbage as test crops. A substantial improvement in soil health was observed with respect to nutrient availability, physical stability, and microbial diversity due to the application of drum compost and traditional vermicompost. Moreover, soil organic carbon was enriched through increased humic and fulvic acid carbon. Interestingly, heavy metal contamination was less significant in vermicompost-treated soils than in those receiving the other treatments. The use of VC and DC in combination with recommended chemical fertilization effectively stimulated crop growth, yield, product quality, and storage longevity for both tomato and cabbage.

Conversion of cropland to forage land and grassland increases soil labile carbon and enzyme activities in northeastern China

Abstract Soil labile carbon (C) and enzyme activities are valuable indicators of changes in soil quality and health. Understanding the changes in soil labile C and enzyme activities under different land uses is important to maintain soil quality and health and for sustainable land use. The primary objective of this study was to investigate the short-term influences of different land uses on SOC, soil labile C and enzyme activities in semiarid alkaline grassland of northeastern China. The experiment was organized as a block design with four replications of each land use treatment. Land use treatments were corn cropland (Corn), alfalfa forage land (Alfalfa), Lyemus chinensis grassland (AG), Lyemus chinensis grassland for mowing (AG + Mow) and restored grassland (RG), which were applied for five years. Total soil organic carbon (SOC), three labile C pools (oxidizable labile C; water-extractable organic C; microbial biomass C) and the activities of four soil enzymes (catalase; urease; alkaline phosphatase; invertase) were determined at the 0–20 cm depth in the five land use treatments. Results showed that soil labile C and enzyme activities were sensitive indicators of land use change. Conversion of cropland to forage land and grassland increased SOC (40.42%), soil labile C measures (25.50%) and enzyme activities (55.60%). However, the responses of different forms of soil labile C and enzyme activities to different land uses were not similar. Under Corn, AG + Mow, AG and RG land uses, the geometric means of labile C (27.01%, 10.95%, 17.52% and 5.11%, respectively) and enzyme activities (40.92%, 13.54%, 11.38% and 7.38%, respectively) were lower than those under Alfalfa, demonstrating that soil labile C and enzyme activities improved more under Alfalfa than under other land uses in northeastern China. Significant correlations were also obtained between SOC, soil labile C measures and enzyme activities. To conclude, soil labile C and enzyme activities can be expected to gradually increase with the conversion of cropland to grasslands and forage land, and planting to alfalfa offers a profitable and sustainable solution to our requirement for pairing forage production with rapid restoration of soil quality in the areas in which soils are not suitable for growing crops in the Songnen Grassland.

Improved or Unimproved Urban Areas Effect on Soil and Water Quality

Construction in urban areas usually results in compacted soil, which restricts plant growth and infiltration. Nutrients may be lost in storm runoff water and sediment. The purpose of this study was to determine if existing lawns benefit from aeration and surface compost additions without the negative impact of nutrient loss in runoff. Four sets of lawns were compared, with or without compost plus aeration, as a paired comparison. Surface bulk density was significantly reduced in the treated lawns (1.32 versus 1.42 Mg·m−3). Visual evaluation of soil structure showed improvement in the treated lawns. Of fifteen measurement dates over four years, four dates showed significantly higher surface soil water contents in the treated lawns compared with the untreated lawns. When compared over time, three of the four treated lawns had significantly higher soil water content than the untreated lawns. Nutrient concentrations in rainfall simulator runoff were not significantly different between treated and control lawns, which showed that compost did not negatively impact water quality. Compost and aeration helped restore soil quality for urban soils of recent construction.

The productive potential of the land and its assessment principles in Ukraine

Getting the maximum economic effect on agricultural lands without environmental performance needs to restore these areas. The main objective of optimum utilization of land resources is a process of territorial organization, in which the need to apply the most effective option to use the whole complex of land resources for the greatest productive potential of agricultural land. The concept of "productive potential" is considered as the combination of characteristics of land and natural conditions, shaped by human society, and determine the nature of the rational use of land in the area of expanded reproduction. In general terms the maximum opportunity in the economy. The productive potential of land is not a sustainable figure. During the agricultural use of the land productive potential is constantly changing due to the gradual improvement or reduction of logistics, soil fertility and obtaining agricultural products. The productive capacity of agricultural land is proposed to assess the following indicators: a qualitative characterization of soils and agricultural technologies. These indicators are as diverse comparative calculation to be posted in stages. First of all, draws attention to the qualitative characteristics of the soil, which is the basis for growing crops. Data on basic indicators of soil to be correct and complex to define parameters of soil and expressed through generalized estimation of fertility. These figures are in agrochemical passport fields. The final calculation serves agrochemical and environmental agrochemical evaluation, filed in points. Modern agricultural technologies is a complex process operations management processes productive crops in artificial ecosystems to achieve the forecasted yields and product quality while ensuring environmental safety and some economic efficiency. Number of applied agricultural technologies depends on the complexity of environmental conditions and the level of planned productivity. The more intense agricultural technologies, especially natural factors must be considered. To improve performance and improvement of production in agriculture advanced countries in the world use precision agriculture. When used precision agriculture systems plant receives the amount of substances which it needs. By fertilizing spot, where they are needed, minimized costs of acquisition Equally important set of measures aimed at improving the natural environment is reclamation. Thanks to the introduction of more productive land reclamation, increasing their resistance to adverse climatic conditions and creates an environment that best meets the requirements that are in agriculture. Bet the use of productive potential site is reduced to an objective assessment of the environmental and economic interests and study the most effective ways to implement them. Prevention of the costs of restoring soil quality and further increase the full net production effects that positively influence the formation of the productive potential of agricultural land. Key words: productive capacity, soil fertility, agricultural technologies, forecasting

In situ remediation and phytotoxicity assessment of lead-contaminated soil by biochar-supported nHAP

In this study, a kind of biochar-supported nano-hydroxyapatite (nHAP@BC) material was used in in-situ remediation of lead-contaminated soil. Column experiments were performed to compare the mobility of nHAP@BC and Bare-nHAP. The immobilization, accumulation and toxic effects of Pb in the after-amended soil were assessed by the in vitro toxicity tests and pot experiments. The column experiments showed a significant improvement in the mobility of nHAP@BC. The immobilization rate of Pb in the soil was 74.8% after nHAP@BC remediation. Sequential extraction procedures revealed that the residual fraction of Pb increased by 66.6% after nHAP@BC remediation, which greatly reduced the bioavailability of Pb in the soil. In addition, pot experiments indicated that nHAP@BC could effectively reduce the upward translocation capacity of Pb in a soil-plant system. The concentration of Pb in the aerial part of the cabbage mustard was 0.1 mg/kg, which is lower than the tolerance limit (0.3 mg/kg). nHAP@BC can remediate Pb-contaminated soil effectively, which can restore soil quality for planting.

Transformation of ex-arable land to permanent grassland promotes pore rigidity and mechanical soil resilience

The conversion of degraded arable land to permanent grassland is widely presumed to be amendatory and is therefore proposed as a climate-smart agriculture strategy, which may rapidly restore soil quality. However, the rate and extent of soil repair will largely depend, on the management practices, deployed in the permanent grassland. In this study, our objective was to assess the effects of no-till and no-renovation management, on aggregation, internal soil strength parameters and pore system dynamics of permanent grassland, established from degraded arable land. Also, we analysed the time dependence of these changes on the some functions of the soil. Undisturbed samples were collected at 3 depths: 0–10cm, 10–25cm and 25–40cm, from permanent grassland, aged 1, 8 and 19-years, and were used to determine water retention and saturated hydraulic conductivity for each sward age. Moreover, compression properties and shear stress parameters at these depths and sward-ages were determined. The results indicated remarkable improvement in pore structure in relation to the age of each sward, which resulted in improved water retention, air and water fluxes with the age of the grassland. The shear parameters and precompression stress data showed differences in the structural recovery timeline at the various depths, highlighting the difference in ecological engineering processes as a function of the time since the grassland was established and the depth considered. Our results indicate that permanent grassland management will contribute to a substantial recovery of pore functions, coinciding with enhanced pore rigidity and increased soil strength which may also influence sequestration potential in the grassland.

The effects of forest type on soil microbial activity in Changbai Mountain, Northeast China

Forty years after clear-cutting mixed old-growth forest (broadleaf/Korean pine) in the Changbai Mountain area (Northeast China), a mixed forest with natural broadleaf regeneration and larch plantation displayed larger microbial biomass and activity in the soil than either a naturally regenerated birch forest or a monospecific spruce plantation. Clear-cutting with limited restoration effort was until the end of the twentieth century the norm for managing primary forests in Northeast China. Forest restoration plays an important role in the recovery of soil quality after clear-cutting, but the effects of different regeneration procedures on forest soil quality remain poorly known in Northeast China. We assessed the effects of three regeneration procedures, i.e., (i) naturally regenerated birch forest, (ii) spruce plantation, and (iii) naturally regenerated broadleaf species interspersed with planted larch on soil quality and microbial activity in the Changbai Mountain area. An old-growth mixed broadleaf/Korean pine forest was used as a reference. Physical and chemical properties and microbial biomass were recorded in the soil. Basal respiration and carbon mineralization were measured with a closed-jar alkali-absorption method. Microbial biomass was smaller in the birch forest and spruce plantation than in the old-growth and the mixed broadleaf/larch forests. Moreover, microbial biomass, microbial quotient, and potentially mineralizable carbon were larger in the mixed broadleaf/larch than in the birch forest, while no difference was found between spruce plantation and birch forest for microbial biomass and microbial quotient. Basal respiration and metabolic quotient were larger in the birch forest as compared to the three other forest types, indicating a larger energy need for maintenance of the microbial community and lower microbial activity in the naturally regenerated birch forest. Mixed broadleaf/larch forest displayed a larger microbial biomass and higher substrate use efficiency of the soil microbial community than either naturally regenerated birch forest or spruce plantation. The combined natural and artificial regeneration procedure (mixed broadleaf-larch forest) seems better suited to restore soil quality after clear-cutting in the Changbai Mountain.

Bioremediation of oil sludge contaminated soil by landfarming with added cotton stalks

A field bioremediation of oil sludge contaminated soil was conducted by landfarming treatment with added cotton stalks in the Shengli oil field. The ability of landfarming treatment was evaluated to reduce petroleum hydrocarbons and restore soil quality. For 39-month landfarming, the initial concentration of total petroleum hydrocarbons (TPH) was 12.57 mg g−1 for oil sludge contaminated soil. The removal efficiency of TPH, saturated fraction and aromatic fraction was 68.48%, 90.04% and 85.55%, respectively. Degradation of TPH followed first order exponential decay kinetics. Soil physic-chemical properties of soil pH, saline alkali degree, nutrients, organic matters and hydrocarbon degraders were greatly improved. The results of Biolog and PCR-DGGE analysis revealed the improvement of soil microbial quantity and diversity, and the isolated predominant 23 strains showed a shift in soil community structure toward the hydrocarbon degrading species including Streptococcus sp., Shewanella sp., Bacillus sp., Pseudomonas sp., Marinobactera sp., Thermoanaerobacter sp., etc.

Soil biochemical properties in brown and gray mine soils with and without hydroseeding

Abstract. Surface coal mining in the eastern USA disturbs hundreds of hectares of land every year and removes valuable and ecologically diverse eastern deciduous forests. Reclamation involves restoring the landscape to approximate original contour, replacing the topsoil, and revegetating the site with trees and herbaceous species to a designated post-mining land use. Re-establishing an ecosystem of ecological and economic value as well as restoring soil quality on disturbed sites are the goals of land reclamation, and microbial properties of mine soils can be indicators of restoration success. Reforestation plots were constructed in 2007 using weathered brown sandstone or unweathered gray sandstone as topsoil substitutes to evaluate tree growth and soil properties at Arch Coal's Birch River mine in West Virginia, USA. All plots were planted with 12 hardwood tree species and subplots were hydroseeded with a herbaceous seed mix and fertilizer. After 6 years, the average tree volume index was nearly 10 times greater for trees grown in brown (3853 cm3) compared to gray mine soils (407 cm3). Average pH of brown mine soils increased from 4.7 to 5.0, while gray mine soils declined from 7.9 to 7.0. Hydroseeding doubled tree volume index and ground cover on both mine soils. Hydroseeding doubled microbial biomass carbon (MBC) on brown mine soils (8.7 vs. 17.5 mg kg−1), but showed no effect on gray mine soils (13.3 vs. 12.8 mg kg−1). Hydroseeding also increased the ratio of MBC to soil organic C in both soils and more than tripled the ratio for potentially mineralizable nitrogen (PMN) to total N. Brown mine soils were a better growth medium than gray mine soils and hydroseeding was an important component of reclamation due to improved biochemical properties and microbial activity in mine soils.