Asian Soil Research Journal
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Exploring the Plant Growth Promoting Potentials of Bacteria Recovered from a Coal Mine Soil for Biorestoration Purpose
No full textAim: Coal mining leads to the degradation of surface soil’s physical, chemical and microbiological properties. However, functional microorganisms (such as plant growth promoting microorganisms) with the potential to produce phytohormones, fix nitrogen, solubilize phosphate, and others, can be effective in restoring coal mine soils (CMS). This study was conducted to explore the plant growth promoting potentials [indole-3-acetic acid (IAA) production and phosphate solubilization] of bacteria isolated from the abandoned Ogbete coal mine, Enugu State, Nigeria.
Study Design: A laboratory study to isolate bacteria from the coal mine soil, screen bacterial isolates for plant growth promoting traits (IAA production and phosphate solubilization), and identify the isolates that tested positive for the traits using 16S rRNA gene sequencing.
Place and Duration of Study: Nucleometrix Laboratory, Yenegoa, Bayelsa State Nigeria, between June 2025 and August 2025.
Methodology: CMS was analyzed for its physico-chemical properties. Isolation and enumeration of bacterial isolates from the CMS were done on Nutrient agar, after which the bacteria obtained were screened for IAA production and phosphate solubilization following standard methods. Bacterium that tested positive for the trait (potential) was identified using 16S rRNA gene sequencing.
Results: The coal mine soil was acidic (pH 5.84), while Total organic carbon (1.31%), Soil organic matter (2.27%), Total Nitrogen (3.89 mg/kg), Total phosphorus (1.04 mg/kg), were below levels required for arable soils. Total heterotrophic bacteria counts (3.5 × 105 CFU/g) of the CMS were below requirement for arable soils. A total of seven (7) bacterial isolates were recovered from the coal mine soil, out of which one (1) isolate was positive for IAA production, but negative for phosphate solubilization. The other 6 isolates were negative for both IAA production and phosphate solubilization. The IAA producing bacterium was identified using 16S rRNA sequencing as Chryseobacterium indologenes.
Conclusion: This study revealed the IAA producing potential of Chryseobacterium indologenes, which could further be exploited for its potential to biorestore coal mine soil and other disturbed soil ecosystems for future agricultural purpose.This study contributes to the United Nations Sustainable Development Goal 15, targeted at restoring and promoting conservation and sustainable use of terrestrial ecosystems
Role of Cover Crops in Mitigating Greenhouse Gas Emissions in Agricultural Systems
No full textAgriculture is a significant contributor to global greenhouse gas (GHG) emissions, particularly carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). At the same time, it offers viable pathways for climate change mitigation through sustainable land management. This systematic literature review evaluates the potential of cover crops non-harvested plant species typically grown during fallow periods to reduce GHG emissions and support climate-smart agriculture. Cover crops influence GHG dynamics through multiple mechanisms, including carbon sequestration, biological nitrogen fixation, and reduced nitrate leaching. They also improve soil health by enhancing organic matter content, stabilizing soil structure, conserving water, and supporting beneficial microbial activity. Drawing from 80 peer-reviewed studies selected from an initial pool of 250, the review categorizes cover crops into leguminous and non-leguminous types. Legumes, such as clover and vetch, fix atmospheric nitrogen, decreasing the need for synthetic fertilizers and associated N₂O emissions. Non-leguminous species like rye and radish scavenge excess nutrients and improve carbon storage. Despite strong empirical support for their environmental benefits, the effectiveness of cover crops varies by species, soil type, climate, and management practices. In some cases, cover crops can even increase N₂O emissions under poorly drained or mismanaged conditions. Adoption of cover crops remains uneven, particularly in the Global South, due to financial, technical, and institutional barriers. Constraints include limited seed access, labor shortages, and lack of policy incentives. This review identifies key research gaps in understanding long-term effects, species mixtures, and cover crop performance under future climate scenarios. To scale adoption and maximize climate benefits, future efforts should focus on improving predictive models, expanding farmer training, and enhancing policy and financial support. Overall, cover crops present a promising, nature-based strategy for reducing agricultural emissions while enhancing soil health and resilience in the face of climate change
Effect of Nitrogen and Phosphorus on Yield and Yield Attributes of Rice (Oryza sativa L.)
No full textThis study investigated the effects of nitrogen (N) and phosphorus (P) fertilization on the growth, yield, and yield-related attributes of rice (Oryza sativa L.) under submerged conditions at Yezin Agricultural University, Myanmar. The experiment utilized a factorial randomized complete block design, testing four N levels (0, 43, 86, and 129 kg N ha⁻¹) and four P levels (0, 6, 12, and 18 kg P ha⁻¹), with three replications during both dry and wet seasons using the Sin Thu Kha rice variety. Results showed that increasing N levels significantly improved plant height, tiller number, SPAD readings, and yield components in both seasons, with maximum yields achieved at 129 kg N ha⁻¹. Phosphorus application also positively influenced growth and yield parameters, though its impact was less pronounced than N, with optimal results observed at 12–18 kg P ha⁻¹. Significant interaction effects between N and P were noted across most parameters, highlighting synergistic nutrient interactions. Notably, N and P had a stronger influence on grain yield during the wet season compared to the dry season. The highest grain yield was obtained with 129 kg N ha⁻¹ and 18 kg P ha⁻¹, highlighting the importance of balanced fertilization for maximizing productivity. These findings offer practical guidelines for optimizing fertilizer use in Myanmar\u27s rice production and emphasize the need for integrated nutrient management tailored to seasonal variations. 
Spatial Analysis of Landslide Susceptibility and Rural Vulnerability in the Gavarud Basin, Western Iran
No full textLandslides are among the most significant geomorphological hazards in mountainous regions and are influenced by various natural and human-induced factors. These events can cause extensive damage to infrastructure, agricultural lands, and human settlements. Given that the Gavarud basin in western Iran lies within the tectonically active Zagros geological unit, identifying landslide-prone areas and assessing the vulnerability of rural settlements is crucial for risk reduction and proper land-use planning. In this study, a 30-meter SRTM (Shuttle Radar Topography Mission) digital elevation model, a 1:100,000 geological map, MODIS satellite imagery, and several spatial thematic layers—including slope, aspect, elevation, distance from faults, rivers, and roads, lithology, and vegetation cover—were used to evaluate landslide susceptibility. The thematic layers were standardized in ArcGIS and weighted using the Analytic Hierarchy Process (AHP) implemented in Expert Choice software. The fuzzy gamma operator was applied to integrate the weighted layers and produce the final susceptibility map. The results indicate that the western and northern parts of the basin exhibit the highest landslide potential. Spatial analysis of rural settlements showed that 52 villages fall within the high-risk zone, 64 villages within the moderate-risk zone, and 186 villages within the low-risk category. The findings provide essential information for risk management, land-use planning, and implementing preventive measures in the Gavarud basin
Evaluating the Efficacy of Organic Manures and NPK Fertilizer in Enhancing Plant Growth in Oil-Contaminated Soil: A Study Using Abelmoschus esculentus (Okra)
No full textThis study evaluates the effects of some organic manures (cow dung manure, poultry manure, fish pond wastewater) and NPK 15:15:15 fertilizer on oil-contaminated soil using Abelmoschus esculentus as a test plant. The research was conducted under controlled conditions at Nnamdi Azikiwe University, Awka, using a randomized complete block design. Soil samples were collected from an oil-contaminated mechanic workshop and treated with various organic and inorganic amendments. Growth parameters, including plant height, stem girth, leaf area, and number of leaves, were assessed over eight weeks. Results indicate that cow dung manure significantly enhanced plant height (100.33% increase), while fish pond wastewater combined with poultry droppings (FP+PD) showed the least increase (14.03%), suggesting a negative synergistic effect. The combination of cow dung and poultry manure (CD+PD) also exhibited a strong positive effect on plant growth. Soil nitrogen levels were highest in FP+PD-treated soils (5.32±1.06), while phosphorus levels were maximized with poultry droppings alone (22.90±5.80). Contaminated soil had the highest potassium levels (54.37±4.38 ppm), likely due to crude oil contamination. Despite amendments, soil pH remained largely unchanged. Leaf production was significantly enhanced by cow dung and fish pond wastewater, with a 100% increase in four weeks, while poultry droppings alone had no effect. Leaf area expansion was highest in the control group (842%), indicating that manure application may not significantly influence light-harvesting capability. Stem girth increased equally (33.33%) across all treatments except in the control (11.11%), with cow dung and fish pond wastewater showing the most rapid impact. Overall, cow dung manure proved to be the most effective treatment for improving soil fertility and enhancing A. esculentus growth in oil-contaminated soil, followed by fish pond wastewater and poultry droppings. These findings highlight the potential of organic amendments in mitigating oil pollution and promoting plant productivity
Allelopathic Effects of Cyperus difformis and Eleocharis atropurpurea along with Manures and Fertilizers on the Weed Growth in Transplanted Aman Rice
No full textAt present, the rice cultivation system is in search of a biological alternative to lessen the harmful effects of chemical herbicides, as it relies heavily on them for managing weeds. This is where allelopathy plays a role, offering a potential alternative to traditional weed control methods in rice farming through the use of residues from allelopathic plants. An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, from July 2019 to December 2019 to study the suppression of weed growth through Cyperus difformis and Eleocharis atropurpurea residues along with Manures and fertilizers in transplant aman rice. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Four weed species belonging to four different families infested the experimental plots. Weed population and weed dry weight were significantly affected by treatment. Highest weed population and dry weight was found in T1 (control) for all weed variety while the minimum was found in T6 (Residues 3 t ha-1 + Vermicompost 2.5 t ha-1 + Fertilizers). The findings of this study demonstrate that combining plant residues with manures and fertilizers has the potential to suppress weed growth and improve the yield of transplanted Aman rice. Therefore, integrating plant residues with manures and fertilizers could serve as a sustainable and environmentally friendly approach for weed control and yield improvement in upcoming crop production seasons
Spatial Characterization of Land Use, Geology, and Hydrology in the Musi River Basin Using Remote Sensing and GIS
No full textThe present study offers an integrated assessment of the physiographic, geological, and land surface characteristics of the Musi River Basin, a sub-catchment of the Krishna River located in Telangana, India. Using satellite imagery, GIS techniques, and Digital Elevation Models (DEM), along with the interpretation of topographic and thematic layers, including drainage, geology, land use/land cover (LULC), soil, and geomorphology, the study provides a comprehensive understanding of the basin’s physical environment. DEM analysis indicates a west-to-southeast flow regime with moderate to high relief in the upper and fringe zones, contributing to a dendritic to sub-dendritic drainage pattern. The geological framework is predominantly composed of Archaean granites, interspersed with localized quartzite and dolerite dykes, which subtly influence terrain morphology and hydrological flow paths. The drainage network exhibits moderate density and texture, reflecting a structurally stable landscape. LULC analysis reveals a dominance of agricultural land, open scrub, and rapidly expanding urban areas, highlighting increasing anthropogenic pressure on the natural environment. Soil types vary from deep black cotton soils in low-lying regions to gravelly red soils in uplands, with spatial distribution strongly correlated to geological and topographic settings. These variations significantly affect runoff dynamics, erosion potential, and groundwater recharge. Geomorphological features such as denudational hills, pediment plains, and buried pediments further modulate hydrological behavior and land degradation processes. This comprehensive spatial analysis, employing DEM-based landform characterization and thematic integration, emphasizes cropland dominance and the interrelationship between soil, geology, and terrain. The findings contribute valuable insights for sustainable watershed management, flood risk mitigation, soil conservation, and strategic land-use planning in the rapidly urbanizing Musi River Basin
Effect of Different Rates of Lime and Split Phosphorus Application on Phosphorus Availability and Yield Performance of Soybean (Glycine max)
No full textSoybean (Glycine max) is a globally significant crop, valued for its high protein and oil content. Under acid soils, amending with lime and split phosphorus fertilizer application can improve the yield of soybean due to an increase in soil phosphorus availability. This study aimed to evaluate the effect of lime rates and split phosphorus (P) application on phosphorus availability and soybean yield, to determine the optimal lime and P levels for soybean cultivation in the study area. Two-season field experiments (monsoon and post-monsoon 2024) were conducted at the Department of Soil and Water Science, Yezin Agricultural University (YAU), using a 4 × 3 factorial RCBD design with three replications. Treatments included four lime levels (0, 1.5, 3.0, 4.5ton ha⁻¹) and three split phosphorus application timings (100% basal, 50% basal + 50% V2, and 50% basal + 25% V2 + 25% R1) at a constant rate of 20 kg P ha⁻¹. The soybean variety, Yezin-15 was used. Results indicated that both the independent and combined applications of lime and split phosphorus significantly improved the yield attributes and overall yield of soybean, as well as the availability of phosphorus in the selected soil. After two seasons, the individual application of lime, L2 (3.0ton ha⁻¹) rate showed better performance for all parameters. In split P application, P2 (50% basal + 50% V2) outperformed with the number of pods plan-1, the number of seeds per pod-1 and seed yield. Also, L2P2 (3.0ton lime ha⁻¹ and 50% basal + 50% V2) treatment provided the maximum P availability and seed yield, the maximum number of pods plant-1, the greatest number of seeds pod-1 in both seasons. This study suggested that further investigations with lime and split-P applications for the long term were necessary
Evaluation of Nutrient Contribution by Sunn Hemp at Different Growth Stages in Paddy Soil
No full textGreen manuring contributes to nitrogen availability through biomass decomposition and also increases the soil carbon sequestration. The study aimed to estimate biomass contribution of sunn hemp at various growth stages and the mineralization of sunn hemp after incorporation into paddy soil under submerged condition, focusing on synchronizing nitrogen supply with rice crop demand. Sunn hemp was harvested at different growth stages (45, 60 and 75 days after sowing) to assess its biomass and nutrient contributions, particularly nitrogen and carbon. The harvested plants were incorporated into the soil, and rice seedlings were transplanted a week later. Nitrogen mineralization was monitored over eight weeks, alongside rice plant nitrogen uptake. The study was conducted at the Department of Agricultural Research, Nay Pyi Taw, with four treatments: control (no sunn hemp), SH45 (45 DAS), SH60 (60 DAS), and SH75 (75 DAS). Analytical results of sunn hemp at different growth stages showed minimal variation, however significant differences were observed in fresh and dry biomass weight. SH75 and SH60 contributed fresh biomass together with nitrogen and carbon three times higher than that of SH45. Nitrogen mineralization from different ages of sunn hemp reached maximum within first two weeks. Considering mineralization percentages, SH60 and SH75 showed continuous mineralization from 1st to 8th week, however mineralization in SH45 declined and approached to zero from 5th to the 8th week. Nitrogen demand of rice plants started at 3rd week of SH incorporation into the soil, reached maximum at 6th week and continued to 8th week. Synchronization between nitrogen supply and demand was observed from the 3rd to the 8th week with the incorporation of SH60 and SH75, whereas in the case of SH45, it was limited to the period between the 3rd and 5th week. The research highlighted the nutrient provision potential of sunn hemp at different ages to rice plant under submerged paddy soil
Investigation of Poly Aromatic Hydrocarbons and Heavy Metals in Soils of Selected Auto Mechanic Workshops in Nimo, Njikoka, Anambra State, Nigeria
No full textAuto mechanic workshop activities and disposal of the wastes into open plots, farms and water drains could pose an environmental risk considering the water table in the east region of Nigeria and shallow bore-holes dug to get water for domestic use. This research aimed at investigating the levels of poly aromatic hydrocarbons (PAHs) and heavy metals (Cd, Cr, Hg, Ni, Pb and V) in soils from four (4) auto mobile mechanic workshops namely; Abba Nimo, Ebengwu Nimo, Oye Nimo and Nimo-Owele Nimo and the control soil sample collected 500m away from auto mechanic activity area at Nimo, Anambra state, Nigeria. The soil samples were prepared in the laboratory following standard procedures and analyzed for 16 US EPA priority PAHs using Gas chromatograph-Buck M910 scientific gas chromatography equipped with flame ionization detector. Total PAHs concentrations in soil from all sampling sites were in the range of 0.1097-1.0916mg/mL. In addition, the dispersion of heavy metals in the soils profile were ascertained using Varian AA 240 atomic absorption spectrophotometer (AAS). The mean levels of Cd, V, Cr & Ni in the soils were within world health organization (WHO) permissible limit while Pb and Hg in some sample sites were above WHO permissible limits for agricultural soils. Lead (Pb) was the most significant contaminant, and its degree of contamination was highest (0.305 mg/kg, 0.481 mg/kg, 0.410 mg/kg and 0.431 mg/kg respectively) followed by Hg which was only found in samples A (0.983mg/kg) and B (1.468 mg/kg).The results obtained from both PAHs and heavy metals analysis indicated that automobile repair activities likely exacerbate pollution issues, as evidenced by the presence of some potential harmful chemicals found in the control sample. This calls for future research on risk assessment and soil remediation of the studied areas. Also, government enforcement agencies should ensure an adherence to proper environmental standard by auto mechanic artisans