Open Journal of Soil Science

Journal Information
ISSN / EISSN: 21625360 / 21625379
Total articles ≅ 359

Latest articles in this journal

Kenneth R. Olson, Khoi Minh Chau
Open Journal of Soil Science, Volume 12, pp 541-570; https://doi.org/10.4236/ojss.2022.1211023

Abstract:
Human exposure to arsenic (As) is primarily through drinking water and food ingestion. Arsenic is naturally present in the environment and has been known as “the king of poisons” since the Middle Ages. It is mutagenic, teratogenic, and carcinogenic and approximately 70% comes from ingested food and 29% from water. Once ingested, arsenic can bio-accumulate in the human body or be excreted. Arsenic in groundwater is a main source of As in humans and the two arsenicals most abundant in water are arsenite (+3 oxidation state) and arsenate (+5 oxidation state). In order of toxicity from the most toxic to least toxic are arsines, arsenites, arsenoxides, arsenates, pentavalent arsenicals, Arsenic compounds, and metallic arsenic. Arsenic accumulates in the body when ingested in small doses. It often takes decades before physical symptoms of As poisoning show. While As is element normally found in the human body, it is highly toxic in excess amounts. The lethal dose for rates is 48 μg/L which translates to 125 mg for a middle-aged male. The maximum safe limit for As ingestion for an average Vietnamese middle-aged male is 220 μg per day. This lethal dosage puts As in a highly toxic category in food and toxicology. Most of the As in the Mekong Delta groundwater is from natural alluvial sediment sources. Other anthropic sources include the burial of millions of Vietnamese with elevated As levels since 1962, industrial sources, smelting by-products, water treatment plants, sewage and wastewater treatment discharges into waterways have added to the Mekong Delta As levels in the soil and groundwater. However, Agent Blue, the As-based herbicide, used during the Vietnam War, did contribute a significant amount (over 1,132,400 kg of manufactured (anthropic) As) to Southern Vietnam landscape. The As spikes and levels in the Mekong Delta soils and groundwater need restoration. The uptake of trace amounts of As in rice is indeed a critical food security and human health issue and requires mitigation.
Souoré Irène, Basga Simon, Doumnang Mbaigane Jean-Claude, Ngaro M’Baïti
Open Journal of Soil Science, Volume 12, pp 523-539; https://doi.org/10.4236/ojss.2022.1210022

Abstract:
The soils of Gadas, object of the present study, are identified on the macromorphological, physico-chemical level and the indices of erodibility are related to their physico-chemical properties. The physico-chemical analyzes were carried out by standard methods. The macromorphological analysis of a toposequence made it possible to identify five types of soils: the lithosols which occupy the high zones of the landscape, the colluvial soils (arenosols, regosols) which are located high on the piedmont, alluvial soils (fluvisols) which are located at the bottom of the slope in the alluvial plain and are the most extensive, topomorphic vertisols, and brown soils formed on granite are located either between a colluvial soil and alluvial soil. Physico-chemical analyzes of the soils of Gadas show that these soils are weakly acidic to neutral, sandy to sandy-clayey, saturated, low in nitrogen and organic matter and characterized by average proportions of exchangeable bases. The study of soil erodibility, based on the use of erodibility indices, showed that alluvial soils and brown soils formed on granites are the most susceptible to erosion, whereas vertisols and colluvial soils are the least vulnerable to erosion.
Stéphanie Batchakoué Maïga-Yaleu, Abdul-Charif Cissé, Sibiry Albert Kaboré, Damien Hauswirth, Oumarou Malam Issa, Maguette Kaire, Ibrahim Bouzou Moussa, Hassan Bismarck Nacro
Open Journal of Soil Science, Volume 12, pp 503-522; https://doi.org/10.4236/ojss.2022.1210021

Abstract:
Forest and landscape restoration (FLR) practices have been reported to improve soil organic carbon stocks (SOCs) and contributing to climate change mitigation. This study aims to evaluate the impact of combined FLR practices, mainly developed in semiarid regions, on SOCs. The SOCs, soil texture, bulk density (ρ), pH, CO2 emissions, and herbaceous biomass were determined at a 0 - 30 cm depth. The experimental design comprised degraded land without FLR practices and three sets of combined FLR practices. These practices included “zaï” + stone bunds + organic manure + assisted natural regeneration (ANR) used to convert degraded land into forest (GF) and cropland (PARL); “zaï” + stone bunds + crop rotation + crop/fallow successions + ANR used to convert degraded land into cropland (OARL) and “zaï”+ stone bunds + organic manure used to convert degraded land into cropland (KARL). SOCs were highest (20.02 t C ha−1) under OARL compared with the other combinations of FLR practices. SOCs increased by 99% (+0.2 t C ha−1⋅yr−1), 58% (+0.3 t C ha−1⋅yr−1) and 13% (+0.2 t C ha−1⋅yr−1) under GF, OARL and KARL, respectively, and decreased by 15% (−0.1 t C ha−1⋅yr−1) under PARL. This study provides additional information explaining SOC variation in restored degraded land through the implementation of a combination of FLR practices. This is useful for recommending the combination “zaï” + stone bunds + crop rotation + crop/fallow successions + ANR to improve SOCs in the semiarid agroecosystem.
Aman Messou, Pétémanagnan Jean-Marie Ouattara, Franck Michaël Zahui, Lacina Coulibaly
Open Journal of Soil Science, Volume 12, pp 490-502; https://doi.org/10.4236/ojss.2022.1210020

Abstract:
The restoration of soils polluted by trace metals (Pb and Cd) by phytoremediation is an innovative and ecologically sustainable solution. The objective of the study was to develop a process of phytoaccumulation of trace metals (Pb and Cd) in soils with the species Panicum maximum. For this purpose, 30 buckets containing soil were used. These included six (06) buckets per dose of soil contamination by Pb and Cd (3 mg/kg and 9 mg/kg of Cd and 100 mg/kg and 300 mg/kg of Pb) and six (6) buckets containing uncontaminated soil (control). During a period of 90 days of experimentation, the concentrations of trace metals in the plant biomass and in the soils were measured. Also, the bioaccumulation (BF) and translocation (TF) factors, the mass of Pb and Cd taken up by the plant were determined. The results showed that the biomass produced was negatively influenced by increasing Pb and Cd concentration. The concentrations of Pb and Cd accumulated by P. maximum varied in the aboveground biomass from 6.48 ± 0.55 to 18.09 ± 0.71 mg/kg (Pb100); from 10.93 ± 0.38 to 23.04 ± 0.79 mg/kg (Pb300); from 0.91 ± 0.02 to 1.50 ± 0.03 mg/kg (Cd3); and from 3.05 ± 0.08 to 5.43 ± 0.09 mg/kg (Cd9) from day 30 to day 90. However, in the root biomass, trace metals (Pb and Cd) ranged from 8.09 ± 0.58 to 22.57 ± 0.86 mg/kg (Pb100); from 29.45 ± 0.49 to 62.35 ± 0.82 mg/kg (Pb300); from 0.66 ± 0.01 to 1.11 ± 0.07 mg/kg (Cd3); and from 2.22 ± 0.08 to 3, 97 ± 0.09 mg/kg (Cd9), from day 30 to day 90. Pb was concentrated in the root biomass and Cd in the aboveground biomass. Bioaccumulation factor values ranged from 0.26 ± 0.02 to 0.99 ± 0.04 (Pb100); from 0.21 ± 0.04 to 0.50 ± 0.06 (Pb300); from 0.83 ± 0.09 to 1.72 ± 0.18 (Cd3); and from 0.70 ± 0.08 to 1.54 ± 0.18 (Cd9). High concentrations of Pb and Cd show a negative effect on the accumulation potential of P. maximum.
Sabiriba Alain Hema, Mamadou Traore, Kalifa Coulibaly, Bazoumana Koulibaly, Hassan Bismarck Nacro
Open Journal of Soil Science, Volume 12, pp 225-241; https://doi.org/10.4236/ojss.2022.126010

Abstract:
The dry faecal sludge (DFS) are potential sources of organic fertilizers because of their high content in nutrients and organic matter, critical for plants growth and soil health maintaining. In Burkina Faso, the DFS are processed in faecal treatment plants. However, after drying, the DFS are most often dumped in the nature without any control or directly used as fertilizer without any idea of their potential risks for human health and the environment. This investigation aimed at physico-chemical and toxicological characterization of the DFS from faecal treatment plants according to the duration of their storage. For this purpose, DFS samples were collected in three (3) faecal treatment plants in Ouagadougou and one in Bobo Dioulasso, in Burkina Faso. The measurements were carried out on pH (H2O), organic matter content, major nutrients (N, P, K), trace elements (Na, Ca and Mg) and metallic trace elements. Indifferently to the faecal treatment plants and the duration of the storage, the DFS showed strong acidity (4.85 ± 0.13 et 6.53 ± 0.10) and low content in total elements (Na à 40.97% ± 9.99%). Values recorded of the trace metallic elements showed there were no risk of contamination when used as fertilizers: (103.9 ± 2.00 mg/kg < Cu < 137 ± 25.69 mg/kg); (710.13 ± 18.97 mg/kg < Zn < 922.30 ± 7.04 mg/kg); (33.03 ± 1.65 mg/kg < Pb < 152.40 ± 19.40 mg/kg); (1.34 ± 0.17 mg/kg < Cd < 1.76 ± 0.04 mg/kg); (34.34 ± 0.27 mg/kg < Ni < 52.32 ± 3.60 mg/kg) et (771.15 ± 18.36 mg/kg < Cr < 1697.83 ± 55.11 mg/kg). The results indicated a high fertilizer potential of the DFS after addressing the issue of their acidity.
Denis Magnus Ken Amara, Ibrahim Benya, Sheku Alfred Kanu, Daniel Hindogbe Saidu, Raymond Morie Musa, Osman Sidie Vonu, Fayia Brima, Joseph Christian Adamu Mboma, Michael Jusu, Foday Turay, et al.
Open Journal of Soil Science, Volume 12, pp 475-489; https://doi.org/10.4236/ojss.2022.1210019

Abstract:
Soil loss through erosion continues to pose serious challenges to increasing the smallholder agricultural productivity in Sierra Leone. While emphasis on sustainable land use practices continue to gain attention among land users, however, the rate of adoption among smallholder farmers is still very low and hence, in most part of the country soil fertility has been declining at alarming rates. In the Njala area, studies have shown that soil loss ranges from moderate to high. Though soil erosion has been identified as a major soil fertility declining factor, however, the effect of land use practices on the inherent resistance of soil materials to erosion is lacking. This study was therefore conducted to assess the effect of land uses on soil erodibility. The results showed that the soils are coarse sandy loam with high sand content. The dispersion ratios and erosion indices of soils under cassava, plantain, maize and guava were above the minimum thresholds of 15.0 and 10.0 respectively, thus indicating that these soils are highly erodible compared to soils under fallow and sweet potato which have dispersion ratios and erosion indices below the minimum thresholds. Clay content was inversely proportional to and significantly correlated with dispersion ratio and erosion index while the correlations between silt + clay, dispersion ration and erosion index, and silt, silt + clay and dispersion ratio were negative and non-significant. Considering the coarse nature of soils, landscape features and high erodibility indices, these soils would need special soil and water conservation practices to counter further degradation. These may include following, agroforestry, silvi-pasture, controlled and rotational grazing. In addition, awareness of sense of self-responsibility and forest policies and regulations are needed.
Saruul Narangerel, Undarmaa Jamsran, Maki Asano, Kenji Tamura
Open Journal of Soil Science, Volume 12, pp 446-474; https://doi.org/10.4236/ojss.2022.129018

Abstract:
The morphology, physicochemical, humic substances and micromorphological characteristics of four soil profiles of the steppe dominant by Festuca lenensis (F. lenensis) at the high mountain and mountain of Khuvsgul, Mongolia were studied. Soils were classified as Regosols and Leptosols at high mountain steppe, Leptosols and Cambisols at mountain steppe. On a high mountain, the plant root distribution, OC, N and moisture contents were high due to its high precipitation and low temperature. The soils show immature characteristics with low available nutrients, weakly developed crumb structure, many semi- and undecomposed plant residues, and few little organic pigments with few excrements. The humic acids with immature to degraded characteristics indicate that the climatic condition of high mountains inhibits the soil decomposition process. Due to extremely different landform positions, there a sharp difference was observed between studied soils on high mountain steppe. On the summit with a flat position, the soil of TSO1 showed finer soil texture with higher CEC, exchangeable Mg2+ and humification degree of SOM compared with the soil of TSO2, which located on the steep slope. This confirms that the abrupt changes in landform on high mountain strongly affect the properties of topsoil. On the mountain steppe, the soil contains higher exchangeable Na+, exchangeable K+ and water soluble at topsoil; however, the plant root distribution, OC, N and moisture contents were lower than that of high mountain soil. Because of warmer air and soil temperature in comparison with that of high elevation, active turnover in humic horizon and chemical weathering process lead to higher available nutrients in mountain steppe. The degraded to well humified characteristics of humic acid, moderately developed crumb structure, a higher component of little organic pigment and many intact excrements indicate that the soil decomposition process and biological activity were higher than that of the high mountain steppe. Our finding suggests that the climatic condition dependent on altitude and landform position at the high mountain and mountain of Khuvsgul had a large impact and played a key role in the soil properties and characteristics of steppe dominant by F. lenensis.
Taanloumi Said Bacar, YiBen Cheng, Yunqi Wang, Kenza Kaboul, Namir Domingos Raimundo Lopes
Open Journal of Soil Science, Volume 12, pp 427-445; https://doi.org/10.4236/ojss.2022.129017

Abstract:
This review paper has been made to assess the past studies reviewed regarding vegetation restoration and its impact on soil organic carbon content. A Vegetation Restoration is an influential technique that can be used to respond to these effects. As a response to the global biodiversity crisis, more restoration actions have been taken. The European Union Council’s results on kinds of diversity after 2010 highlight words like stopping biodiversity loss and the breakdown of ecological systems in the European Union. The United Nations Conference on Biological Diversity’s growth strategy for 2022, which includes restoring at least 15% of degraded ecosystems, has made this possible. Soil types are among the most vulnerable resources on the planet due to factors such as climate change, land degradation, and the reduction of biodiversity. Organic Carbon, the top meter of soil, could potentially store three times as much carbon as is found in the air and almost twice as much as in plants. For the systematic literature review, past papers on vegetation restoration have been extracted from the latest papers of 2013 and onwards to 2022. The summary of results included key findings of the papers, the interpretation of papers reviewed, and the relevant references. Thirty papers were reviewed and selected from authentic databases and assessed that vegetation restoration significantly affects soil organic carbon (SOC). The findings also exhibit that the primary sources of prediction for SOC dynamics include changes in soil properties, quality, the number of carbon inputs, and the composition of the C pool. Vegetation restoration also plays an important role in improving the services of ecosystems such as controlling the erosion of soil and increasing the carbon sequestration. Moreover, some papers concluded that vegetation restoration positively influences on the SOC. Moreover, to increase the generalizability of the study, implications and future research indications have also been included in the end.
Kenneth R. Olson, David R. Speidel
Open Journal of Soil Science, Volume 12, pp 363-426; https://doi.org/10.4236/ojss.2022.128016

Abstract:
During the Vietnam War, millions of liters of six tactical herbicides were sprayed on the southern Vietnam landscape to defoliate forests, to clear military perimeters and to destroy enemy food supplies. The environmental and human health impacts of spraying these herbicides, especially Agent Orange and those formulated with mixtures that included 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) which was contaminated with 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) have been documented over the last 60 years. The dioxin TCDD clean-up efforts at former military bases and other Vietnam hotspots are ongoing. However, the lesser-told story was the environmental and human health impacts on the communities and chemical plant workers who manufactured Agent Orange and other herbicides that became contaminated with dioxin TCDD in the manufacturing processes at seven locations in the United States and one site in Canada. The pollution at these chemical plant sites, adjacent rivers and groundwater is well known within each affected state or province but not widely recognized beyond their localities. In this paper we assess the national long-term effects on land, groundwater and river resources where Agent Orange and other agricultural herbicides containing 2,4,5-T with unknown amounts of dioxin TCDD were manufactured, transported, and temporarily stored. The sites where residual tactical herbicides with contaminated by-products were applied to public lands or disposed of by military and civilian workers within the United States and Canada are identified. After 60 years, these communities are still paying the price for the U.S. Government, DOD and USDA decisions to provide and use agricultural herbicides as tactical chemical weapons during the Vietnam War (1962-1971). There have been human health issues associated with the chemical manufacture, transport, storage and disposal of these herbicides related to workers who moved these chemical weapons from United States and Canada to SE Asia. Most of these dioxin contaminated tactical herbicides were transported via railroads to ports at Mobile, Alabama and Gulfport, Mississippi. They were then loaded on ocean-going ships and transported via the Panama Canal for use during the Vietnam War. The objective of this study is to document the environmental and human consequences of the manufacture of tactical herbicides with dioxin TCDD and arsenic on the chemical plant, transportation, application, storage and disposal workers. The costs of cleanup of these North America chemical plant sites, transportation corridors, temporary and long-term storage areas, supply chain storage facilities with residual tactical herbicide, application, and disposal sites to date, is in the billions of dollars. Billions have been spent on hazardous waste incineration to destroy the dioxin TCDD or bury it in certified landfills. Government mandated environmental covenants are on titles of properties still contaminated with high levels of dioxin TCDD. If landowners attempt to rescind land use restrictions, many more billions of dollars will be needed to finish the environmental cleanup and restore natural resources. These cost estimates do not include the billions of dollars needed to treat the effects of dioxin TCDD exposure of U.S. and Canadian civilian workers who manufactured and handled these contaminated herbicides during the Vietnam War as well as address human health issues of their offspring.
Kalifa Coulibaly, Baba Ouattara, Souleymane Ouédraogo, Nadine Andrieu, Hassan B. Nacro
Open Journal of Soil Science, Volume 12, pp 339-362; https://doi.org/10.4236/ojss.2022.128015

Abstract:
Conservation agriculture (CA) is one option for dealing with such a challenge, but its main difficulty in West Africa is in maintaining permanent soil cover, particularly with crop residues, due to their preferential use for livestock fodder. The aim of our study was to determine the effect of crop residue mulching on the efficiency of cropping systems based on the principles of conservation agriculture. The experimental design was based on on-station experiments, intended to assess the specific effect of different levels of crop residue mulching on the biological and chemical soil fertility parameters, while in on-farm experiments we mainly assessed the ability of farmers to actually collect crop residues for soil cover and the associated effects on weeds and yields. The on-station experimental design was in fully randomized factorial blocks comprising five treatments and three replicates. The treatments compared the conventional system, tillage and cropping without mulching, and CA systems with 1 ton, 2 tons, and 4 tons of straw per hectare in plots of 10 m2. The effects of CA on the macrofauna, respiratory activity, and soil chemical parameters were evaluated in the 2014 and 2015 growing seasons. For the on-farm experiments, the conventional and CA practices of 15 farmers were compared to conventional practices in 2013 and 2014 in plots of 626 m2. The on-station results showed that the presence of crop residue mulching induced an increase in the density of termites. A significant release of carbon dioxide (CO2) in the CA treatments compared to the conventional treatment was also observed. For the chemical parameters (pH, N, P and K) were significantly and positively affected by mulch in the top 5 centimeters of soil. The on-farm experiments confirmed the difficulty of farmers in collecting enough biomass, with negative effects on grass cover leading to generally lower yields than conventional treatments. Other practices also affected the results, such as the maize sowing date, the gap between sowing and weeding, the gap between sowing and urea supply, the number of years of CA practices in the plot and, the gap between maize sowing and cowpea sowing. For the farmers having the human resources to collect enough crop residues for soil cover and follow the steps of the crop management sequences, it was possible to maintain yields compared to the conventional practice.
Back to Top Top