GIS-Based Assessment of Soil Chemical and Physical Properties as a Basis for Land Reclamation in Toshka Area, Aswan, EGYPT

The accurate assessment of soil properties is a crucial factor for composing and implementing reclamation plans. The main objective of this study was to evaluate soil chemical and physical properties and calculate the chemical and fertility index for assisting land reclamation in Toshka area. The Toshka area is located between latitudes 31°32'N and 31°36'N and longitudes 32°40'E and 32°60'E. GIS was used to select 16 sites. The results revealed the soil has undesirable characteristics. The soil pH ranged from slightly alkaline to moderately alkaline. Furthermore, it was characterized as saline (with a ECe of 4.65 - 11.45 dS⋅m−1) and moderately calcareous soil (with CaCO3 at 11.85% - 17.20%). The soil had a low soil organic matter content which did not exceed 0.18%. The soil was dominated by a sandy loam texture (62.50%) followed by a sandy clay loam texture (18.75%). The bulk density, total soil porosity and saturated hydraulic conductivity values varied with 1.38 - 1.55 Mg⋅cm−3, 41.85% - 48.45% and 1.20 - 3.34 cm⋅h−1, respectively. The chemical index ranged from low to moderate quality. The correlations between the parameters osculated between negative and positive. Therefore, the soil may be reclaimed if the soil properties are improved and crop selection is optimized for this soil.

Zoning of land reclamation in coal mining area and new progresses for the past 10 years

Coal mining disturbed land is the main sources of land reclamation in China.With the rapid increase of economy and coal production,more and more land has been disturbed by construction and coal mining;thus,land reclamation has become highlights in the past 10 years,and China is boosting land reclamation in mining areas.Disturbance characteristics vary from region to region,according to natural and geological conditions,coal mining area land reclamation was divided into 3 zones,which are eastern,western and southern.Reclamation strategies are focused on prime farmland protection in eastern and ecological restoration in western and southern zones,respectively.Several innovative reclamation technologies and theories for the past 10 years were introduced in this paper,including concurrent mining and reclamation,Yellow river sediments backfilling,self-reclamation,and topsoil alternatives in opencast mines.Besides,in the government regulation and legal system building respect,several important laws and regulations were issued and implemented in the past 5 years,promoting land reclamation management and supervision greatly.Land reclamation is and will still be one of the most important parts of coal industry in the future,and more efforts and funds are expected to get involved.

Ecological rebuilding and land reclamation in surface mines in Shanxi Province, China

It is well known that the mining industry produces a large amount of derelict land, and causes pollution of water loss and soil erosion as well as other environmental damage in China. As land is under pressure in China, it is now policy to restore or reclaim land despoiled by mining, the aim being to develop sustainable and healthy arable land ecosystems. This paper outlines the principles and approaches of ecological restoration, which have been adopted in Shanxi Province with reference to three typical surface mines. In the research, the principles of ecological engineering and ecological succession are considered as the critical theories of ecological restoration in mine degraded land. Meanwhile, the paper made a comparative research on main links of ecological rebuilding in three surface mines in Shanxi Province, which include new land construction, treatment of toxic substances, control of soil erosion, fertility management, irrigation, ecological planning and the establishment of legislation systems. As the research demonstrated, for successful restoration, new land construction is the fundamental framework, but it must be integrated with ecological engineering including ecological planning, the control of soil erosion and vegetation establishment and ecosystem creation in order to optimise land productivity and soil fertility. In addition, the establishment of the legislation systems and organization of administration are also indispensable aspects of ecological rebuilding in mined land.

Effects of cluster land reclamation projects on storm surge inJiaojiang Estuary,China

Variations in coastline geometry caused by coastal engineering affect tides, storm surges, and storm tides. Three cluster land reclamation projects have been planned for construction in the Jiaojiang Estuary during the period from 2011 to 2023. They will cause significant changes in coastline geometry. In this study, a surge-tide coupled model was established based on a three-dimensional finite-volume coastal ocean model （FVCOM）. A series of numerical experiments were carried out to investigate the effects of variations in coastline geometry on tides, storm surges, and storm tides. This model was calibrated using data observed at the Haimen and Ruian gauge stations and then used to reproduce the tides, storm surges, and storm tides in the Jiaojiang Estuary caused by Typhoon Winnie in 1997. Results show that the high tide level, peak storm surge, and high storm tide level at the Haimen Gauge Station increased along with the completion of reclamation projects, and the maximum increments caused by the third project were 0.13 m, 0.50 m, and 0.43 m, respectively. The envelopes with maximum storm tide levels of 7.0 m and 8.0 m inside the river mouth appeared to move seaward, with the latter shifting 1.8 km, 3.3 km, and 4.4 km due to the first project, second project, and third project, respectively. The results achieved in this study contribute to reducing the effects of, and preventing storm disasters after the land reclamation in the Jiaojiang Estuary.

The ecological cost of land reclamation and its enlightenment to coast sustainable development in the northwestern Bohai Bay,China

Land has been widely reclaimed in large area in coastal zones all over the world to relieve the pressure of land shortage,promoting social development and economic growth.Asia has become a focus of land reclamation with the rapid industrialization and urbanization.From the Binhai New Area of Tianjin to the Caofeidian New Area of Tangshan,the undergoing project of land reclamation on the northwest coast of Bohai Bay,China,is the largest in the world.To clarify the environmental issues and benefit sustainable development of the coastal zone,we conducted both retrospective and predictive assessments of the ecological cost caused by land reclamation on the northwest coast of Bohai Bay,China.We calculated the ecological costs of ten aspects of the four ecosystem services,i.e.,supply,regulation,support and culture,with the monetary estimate approach.The results indicate that the ecological cost of the new land reclamation is US$971.9 million from 2000 to 2010 and that the cost will be US$702.1 million from 2010 to 2020.The costs of gas regulation and marine food supply account for the greatest parts of the total value.Suggestions for land reclamation oriented to sustainable development in the study area are put forward,including a rational planning based on the comprehensive evaluation,reducing the amount of land reclamation area,optimizing the structure of the reclaimed land,reclaiming land with the concept of ＂low impact development＂ and implementing ecological compensation mechanisms,etc.

Effect of Gully Land Reclamation on Soil Organic Matter and Carbon Contents

[Objectives]This study was conducted to investigate the effects of Yan an gully land reclamation project on farmland soil organic matter and carbon contents.[Methods]Through indirect sampling and random sampling methods,soil samples were collected from six areas of Baota District,Ansai District,and Zichang County in Yan an City,before and after gully land reclamation,and the organic matter and soil organic carbon contained in them were determined.[Results]Through sampling experiments,we initially analyzed the changes of the above components in the land consolidation areas after different years and the reasons for the changes:①after the Yan an gully land reclamation project was implemented,the soil organic matter and carbon contents increased;②directing at the improvement of soil organic matter and carbon content different years after the consolidation,the improvement ranked as 5 a>2 a>1 a;and③correlation analysis showed that there was a significant positive correlation between soil organic matter and carbon contents.[Conclusions]This study provides scientific decision-making and theoretical basis for the construction of high-standard farmland in gully areas and the implementation and promotion of gully land reclamation projects.

Impact of Land Reclamation on the Vegetal Cover of Bayelsa State, Nigeria

The study examined the impact of land reclamation on vegetal cover in Bayelsa State.For the purpose of this study,both quantitative and quali­tative research methods were adopted.Field observations,questionnaire survey and landsat imagery of land cover changes in the year 1986 and 2018 were generated from the global ground cover facility stream.The time series study design and supervised classification of the image processing were adopted to determine the impact of land reclamation on vegetal cover of the study area.It was therefore recommended that recovery of land will make strategic urban planning initiatives sustainable in overcrowded areas and institutions should also put in place laws and strategies to regulate rec­lamation activities across the region and also geo-spatial skills should be put in place to help quantify the dynamics,trends and rate of reclamation induced land cover change in the environment.

Perception of Disasters and Land Reclamation in an Informal Settlement on Reclaimed Land:Case of the BASECO Compound,Manila,the Philippines

Southeast Asia's coastal urban areas continue to grow,with land reclamation fast becoming an important option for megacities to address issues of economic growth and increasing population density.Experts are divided over the advantages and disadvantages of land reclamation,though this process continues unabated,exposing settlements to coastal hazards.The Bataan Shipping and Engineering Company(BASECO)compound is an informal settlement on reclaimed land in Manila,the Philippines.How informal coastal settlements view disaster risk and their more pressing socioeconomic needs is crucial to understanding the potentials and repercussions of land reclamation.Using a topographic survey,a questionnaire survey,and the protective action decision model,this study explored the perception of disasters and land reclamation of informal settlers who are living on reclaimed land.The study found that people are aware of disaster risks,but are more concerned with everyday needs.They are divided on the issue of further land reclamation.Residents on the original non-reclaimed land view it as a coastal defense,while those on reclaimed land fear potential eviction.Despite this,all locations in the community are concerned with the loss of jobs,economic opportunities,and eviction,rather than potential disasters.

Reclamation-oriented spatiotemporal evolution of coastal wetland along Bohai Rim,China

Coastal wetlands are located in the ecotone of interaction between the land surface and sea,and anthropogenic activities extensively interfere with these wetlands through the reclamation of large tidal wetlands and destruction of the function of the ecosystems.In this study,we investigated the dynamic evolutionary characteristics of the Bohai Rim coastal area over the past 40 years using the Modified Normalized Difference Water Index,the fractal dimension,object-oriented classification,the land-use transfer trajectory,and regression analysis.Additionally,we quantified and monitored the evolution of reclamation and analyzed the correlation between reclamation and coastal wetlands based on 99 Landsat-2,-5,and-8 images(at 60 m and 30 m spatial resolution) over the period 1980–2019.The results are as follows.(1) The coastline of the Bohai Rim increased by 1 631.2 km from 1980 to2019 with a zigzag variation.The artificial coastline increased by 2 946.1 km,whereas the natural coastline decreased by 90%.(2) The area of man-made wetlands increased by 3 736.9 km~2,the area of construction land increased by 1 008.4 km~2,and the natural wetland area decreased by 66%.The decrease of tidal flats is the main contributor to the decrease of natural wetland area(takes account for 91.1%).Coastal areas are affected by intense human disturbance,which was taken place across a large area of tidal flats and caused the landscape to fragment and be more heterogeneous.The coastal zone development activities were primarily concentrated in the southern Laizhou Bay,the Yellow River Delta,the Bohai Bay,the northern Liaodong Bay,and the Pulandian Bay.The solidified shorelines and increase in sea level have resulted in intertidal wetlands decreasing and impaired wetland ecology.(3) There is a good agreement between reclamation and the size of the coastal wetlands.Both land reclamation and the reduction in coastal wetland areas are significantly related to the population size,fishery output value,and urbanization rate.In summary,human activities,such as the construction of aquaculture ponds and salt pans,industrialization,and urbanization,are the primary forces that influence the environmental changes in the coastal region.This study is beneficial for establishing and improving the systems for the rational development and utilization of natural resources,and provides theoretical references for restoring wetland ecology and managing future reclamation activities in other coastal zone-related areas.

Carbon footprint of crop production in Heilongjiang land reclamation area,China

In the context of global warming,agriculture,as the second-largest source of greenhouse gas emissions after industry,had attracted widespread attention from all walks of life to reduce agricultural emissions.The carbon footprint of the planting production system of the Heilongjiang Land Reclamation Area(HLRA),an important commodity grain base in China,was evaluated and analyzed in this paper.On this basis,this paper sought feasible strategies to reduce carbon emissions from two aspects:agronomic practices and cropping structure adjustment,which were particularly crucial to promote the low-carbon and sustainable development of agriculture in HLRA.Therefore,using the accounting methods in IPCC and Low Carbon Development and Guidelines for the Preparation of Provincial Greenhouse Gas Inventories compiled by the Chinese government,relevant data were collected from 2000 to 2017 in HLRA and accounted for the carbon emissions of the planting production system in four aspects:carbon emissions from agricultural inputs,N_(2)O emissions from managed soils,CH_(4) emissions from rice cultivation and straw burning emissions.Then carbon uptake consisted of seeds and straws.Finally,with farmers'incomes were set as the objective function and carbon emissions per unit of gross production value was set as the constraint,this paper simulated and optimized the cropping structure in HLRA.The results showed that there was a“stable-growing-declining”trend in the total carbon emissions and carbon uptake of the planting production system in HLRA,with total carbon emissions of 2.84×10^(10) kg and total carbon uptake of 7.49×10^(10) kg in 2017.In the past 18 years,carbon emissions per unit area and carbon emissions per unit of gross production had both shown a decreasing trend.To achieve further efficiency gains and emission reductions in the planting production system,it was recommended that the local governments strengthen the comprehensive use of straw resources,optimize irrigation and fertilization techniques,and adjust the cropping structure,i.e.,increase the planting area of maize and soybeans and reduce the planting area of rice,and increase subsidies to protect the economic returns of planters.

Optimization and Control in the Low-carbon Reclamation of Damaged Land in Mine Areas

The process of exploiting mining land is the process of carbon increasing. The goal of top-level design of the mine land reclamation is not clear, which causes the reducing of carbon sink capacity. The mine land reclamation program targeted poorly, which is bad for the control of overall carbon resource and emission. According to the requirements in regional division of encouraged, restricted and prohibited development, in various regions, multiple objectives were set as to maximize economic benefits and not to reduce the carbon sinks level of mine area, using Markov process optimization land-use structure, and based on the land type and characteristics, by floating changing, increasing or decreasing, land exploitation structure was adjusted to meet the need of low-carbon mine land exploitation.

Simulation and analysis of Chloride concentration in Zhoushan reclamation area

Zhoushan City in Zhejiang Province is the focus of China's reclamation area, and it also has a great influence on the groundwater quality. Based on the observed data of groundwater level and chloride ion concentration, groundwater quality in the next 6 years in Zhoushan area is predicted and analyzed by using groundwater numerical simulation software GMS. According to the comparison of observed groundwater level and simulated groundwater level at the end time, it is found that the whole water level in the filling area has the small fluctuation, which is within the range of 1 m. And the highest concentration of chloride ion is in the eastern coastal area. The prediction results indicate that there is no obvious trend of sea water with high chloride ion concentration to land. Under the condition of the current groundwater utilization, the groundwater level in Donggang sea area of Zhoushan is stable, and the chloride ion concentration has a slight decrease trend.

Environmental issues from coal mining and their solutions

The environmental challenges from coal mining include coal mine accidents,land subsidence,damage to the water environment,mining waste disposal and air pollution.These are either environmental pollution or landscape change.A conceptual framework for solving mine environmental issues is proposed.Clean processes,or remediation measures,are designed to address environmental pollution.Restoration measures are proposed to handle landscape change.The total methane drainage from 56 Chinese high methane concentration coal mines is about 101.94 million cubic meters.Of this methane,19.32 million,35.58 million and 6.97 million cubic meters are utilized for electricity generation,civil fuel supplies and other industrial purposes,respectively.About 39% of the methane is emitted into the atmosphere.The production of coal mining wastes can be decreased 10% by reuse of mining wastes as underground fills,or by using the waste as fuel for power plants or for raw material to make bricks or other infrastructure materials.The proper use of mined land must be decided in terms of local physical and socio-economical conditions.In European countries more than 50% of previously mined lands are reclaimed as forest or grass lands.However,in China more than 70% of the mined lands are reclaimed for agricultural purposes because the large population and a shortage of farmlands make this necessary.Reconstruction of rural communities or native residential improvement is one environmental problem arising from mining.We suggest two ways to reconstruct a farmer's house in China.

Improvements of marine clay slurries using chemicale-physical combined method(CPCM)

In this paper, the effectiveness, applicability and validity of chemicalephysical combined methods（CPCMs） for treatment of marine clay （MC） slurries were evaluated. The method CPCM1 combineschemical stabilization and vacuum preloading （VP）, while CPCM2 is similar to CPCM1 but includes boththe application of surcharge and use of geo-bags to provide confinement during surcharge preloading.The key advantage of CPCM2 using geo-bags is that the surcharge can be immediately applied on thechemically stabilized slurries. Two types of geo-bags were investigated under simulated land filling anddyke conditions, respectively. The test results show that the shear strength （cu） of treated slurry byCPCM2 is generally much higher than that by CPCM1. Besides, the use of CPCM2 can significantly reducethe treatment time due to the short drainage paths created by geo-bags. Overall, CPCM2 allows fasterconsolidation and higher preloading that help to achieve higher mechanical properties of the stabilizedslurry. There are consistent relationships between cU and water content of slurries treated by CPCM2.Several important observations were also made based on comparisons of experimental data. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

Ecosystem services dynamics response to tremendous reclamation in a coastal island city

Introduction:Ecosystem services are the benefits delivering from the natural environment to human society.Ecosystem services are regarded as important tools for decision-makers to understand the impacts of land use and land cover(LULC)change.Outcomes:The dynamic of four primary ecosystem service indicators were assessed over 1984–2014 based on InVEST model and their responses to LULC changes have been analyzed by the ecosystem service change index(ESCI)and ecosystem service state index(ESSI).Our results confirmed the significant increment in land reclamation in Zhoushan City and over half of the reclamation area was used for human-induced urbanization and over a quarter for the fishery.For the whole territory,the most significant LULC conversions were observed between agricultural land and urban.The study period witnessed the degradation of habitat quality and soil sediment,an increment of the water yield and no significant change of carbon storage.Discussion and Conclusion:Most changes in LULC are significantly related to the dynamics of ecosystem services,which were more impacted in the reclamation area than the rest of the city.Our study highlights the importance of ecosystem service assessments for sustainable land planning and securing economic development.

Comparison of hydrodynamic influence between different types of bay reclamations

Different reclamation types to be used for the tidal flat have different hydrodynamic influences on the bay. Numerical experiments based on the land reclamation（LR） and the mariculture reclamation（MR）, respectively, are conducted for the same reclamation project in the Shuangpantu, for quantitative comparisons. Results show that the MR has less influence on the hydrodynamic environment than the LR. The difference is more than 50%.

Earthworm community development in soils of a reclaimed steelworks

Long-term studies are essential to learn earthworm community development and soil formation post reclamation.Investigations were undertaken at a former steelworks site at Hallside,near Glasgow,UK,reclaimed in the 1990s using a mixture of colliery spoil and sewage sludge.The site was largely planted for production of short rotation coppice willow(Salix spp.).Earthworm inoculation formed a part of the restoration process.Minimal monitoring occurred in the interim,but some records of earthworm sampling existed in 2000 and 2005.This study focused on monitoring earthworms and soil properties across the site,drawing comparisons with adjacent unspoiled soil.Results showed that after 22 years,a species-rich community of earthworms(n=16)colonized the site,with endogeic Aporrectodea caliginosa being dominant by number and anecic A.longa by mass.Across the site,earthworm community density and biomass were 208 individuals m^(-2) and 71 g m^(-2),respectively.The Shannon diversity index for earthworms was 1.89,with an evenness of 0.68.The sewage sludge increased the soil organic matter,but the stone content of the colliery spoil prevented digging in some locations.Soil chemistry had no negative effect on earthworms,but the compacted substrate did hinder water infiltration.Earthworms colonized the reclaimed site from adjacent areas,and community structure and density below well-drained,scrub-free willow,birch,and grassland were not significantly different(P>0.05)from those of the adjacent unspoiled areas.The results show that the historical earthworm inoculation was unnecessary and badly timed.Future reclamations of similar sites can learn from this investigation.

Impact of interlayer on moisture characteristics of reclaimed soil backfilled with Yellow River sediments

Underground coal mining causes land subsidence,and backfilling with Yellow River sediment is an effective reclamation technology to restore farmland in China.To date,two-layer soil reconstructed(TSR)for subsided land reclamation resulted in poor capacity to retain water.To solve this problem,multi-layered soil reconstructed(MSR),sandwiching soil interlayers between sediment,was developed as a new reclamation strategy with Yellow River sediment.In order to evaluate the impact of soil interlayer on moisture characteristics,laboratory experiments of infiltration and evaporation were conducted.Two control treatments(CK1,CK2)and four experimental treatments(T1-T4)were designed.CK1 was undamaged farmland,CK2 was conventional reconstructed two-layers soil profile(filled sediment with 40 cm soil cover).T1-T4 were multiple-layers soil profiles sandwiching different structures of soil interlayers between sediment layers.The results indicated that putting interlayers into sediment reduced water leakage and water evaporation,improved the water-holding capacity of conventional two-layer soil profiles.The total thickness of soil interlayers of 30 cm(T3 and T4)was better than 20 cm(T1 and T2)and two soil interlayers(T2)were better than one(T1)on water-holding capacity.Furthermore,the best reconstructed soil profile was T3,sandwiched two soil interlayer and the first thickness was 20 cm.This treatment had the greatest improvement on soil water holding capacity with an increase of 49.14%compared to CK2 at the end of the evaporation and was closest to CK1(402.31 mm).This study provided experimental evidence that compares with TSR,MRS improved the moisture characteristics of backfilling with Yellow River sediment.