Asian Soil Research Journal
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Concentration and Health Risk Assessment of Heavy Metal in Roadside Soil in Eket, Akwa Ibom State, Nigeria
No full textAims: This study determines the heavy metal impacts on roadside soils and its potential health hazards in Eket, Akwa Ibom State, Nigeria.
Background: Roads affect natural environment to a large extent because automobile act as line sources of heavy metal pollutants. Emission from heavy traffic have been reported to contain Pb, Cd, Zn and Ni which are present in fuel as anti-knock agent. Heavy metals in the soil can also generate airborne particles and dust which may affect the quality of air. Inhalation of substantial quantities of heavy metal particle over period of time may add to human body burden of the metals and constitute health risk.
Methodology: Roadside soil samples were collected from Mobile Matt (MM), Marina Junction (MJ), Uqua Junction (UJ) and Fongetok Junction (FJ) in Eket, a city in Akwa Ibom State of Nigeria and analysed using Atomic Absorption Spectrophotometer. Risk assessment quantification was calculated including potential ecological risk index Eri, health risk assessment, non-carcinogenic risk assessment and carcinogenic risk assessment. The concentrations of heavy metal were applied to assess the adult and children’s health risks both carcinogenic and non-carcinogenic. Hazard quotient (HQ) calculated to determine non-carcinogenic health risk for each individual heavy metal element.
Results: The findings revealed that Eri is divided into three main categories, low, high and very high risk at the four sampling junctions in the study area. High and very high risk is due to high Potential Ecological Risk Index Eri of Cd 252.6 at MJ, 408 at UJ, 259.8 at FJ and 301.2 at MM. Risk index RI is also divided into considerable and high risk. High RI is due to high values of Eri caused by Cd and Pb at different sampling junctions. Heavy metals pose no harmful effect on both adult and children\u27s health as HI 1. The LCR for ingestion, inhalation and dermal contact for adults and children resulted from Pb and Cd. For Cd, LCR is within the threshold value of 1 × 10-6 – 1 × 10-4 which is widely considered acceptable except at MJ adult is 1 × 10-7. For Pb, LCR is in the range of 1 × 10-4 which is considered to have significant health effects on adults and children.
Conclusion: It is therefore expedient that measures to combat further contamination of soil by Cd and Pb be taken to keep the environment clean and safe for humans
Seasonal and Depth-dependent Distribution of Denitrifying Bacteria and N₂O Emission Potential in Eastern Georgian Soils
No full textBackground: Denitrifiers are not limited to free-living organisms. Some are part of biofilms and microbial aggregates in natural or engineered systems, such as wetlands, wastewater treatment plants, and bioreactors. In these environments, stratification of oxygen and nitrate concentrations facilitates microzones conducive to partial or complete denitrification.
Aim: The present study aimed to explore the distribution of denitrifying bacteria and the emissions they produce are of great interest both from an agricultural and ecological perspective. From the soils we studied, it is possible to generalize and determine the general denitrifying activity in the soils of many countries.
Methodology: The study was carried out at Department of Microbiology, Sukhumi State University during 2023-2024. Denitrifying bacteria were studied in the liquid phase of Giltai, the denitrification process was described by color reaction. For the quantitative calculation of denitrifiers in the liquid phase, we used the McCready system.
Results: The quantitative composition of denitrifying bacteria distributed in brown, black soil, alluvial and anthropogenic soils of Eastern Georgia has been studied according to the depth of the studied soils (5,10,25 cm). Samples were taken in all four seasons of the year. The soil types and depths favorable for the spread of denitrifying bacteria have been determined. The influence of acidity, salinity, moisture, the amount of hydrolyzable nitrogen and the seasonality of the year on their number has been determined.
Conclusion: The increase in denitrifiers in anthropogenic soils may be a result of increased moisture. The efficiency of the denitrification process is highest in alluvial soils, at neutral pH (7.0-7.4) and optimal moisture (20-30%). N₂O emissions may increase during the winter season
Nitrogenous Fertilizer Application Rates and Plucking Intervals on Tea (Camellia sinensis (L.) in Eastern Africa: Effects on Soil Nitrogen, Phosphorous, and Potassium
No full textEastern Africa tea grows in high rainfall areas where nutrients depletion through leaching, surface run-off in addition to removal with crop can be high. Nutrients replenishment through fertilizer applications is therefore necessary. The recommended fertilizer application rates and harvesting intervals for tea in Eastern Africa are uniform despite varying environmental factors. These varying environmental factors, nitrogen fertiliser and plucking intervals caused variations in tea yields, quality and leaf nutrients. However, comparison of levels of macronutrients (N, P, K) levels and if the macronutrients levels and influenced by rates of nitrogen fertiliser and plucking intervals in the eastern Africa tea soils have not been documented. The effects of NPKS 25:5:5:5 fertilizer rates and plucking intervals on soil nitrogen, phosphorous and potassium in Eastern Africa were evaluated. Soil samples were obtained from fertilizer trials laid out as 5x3 factorial design replicated three times at each site (Timbilil, Changoi, Arroket (Kenya), Maruku, Katoke (Tanzania), Kitabi and Mulindi (Rwanda)) on clone TRFK 6/8 tea. The rates of nitrogen fertilizer were 0, 75, 150, 225 and 300KgN/ha/year while plucking intervals were7, 14 and 21 days. Soils were sampled at 0-10, 10-20, 20-30, 40-60 cm soil depths. Soil N was determined by Kjeldhal method while P and K using ICP-AES. These results demonstrate that although these soil are classified tea growing areas, soil nutrients levels vary widely. Plucking intervals had no influence on soil N, P, and K levels at all sites, demonstrating the plucking interval is not a major factor causing changes in soil nutrients levels. Increasing nitrogen rates increased (p≤0.05) soil N and P levels but lowered (p≤0.05) soil K. Continuous use of high rates of nitrogenous fertilizers may require remedial application of K to ensure optimal levels are available to tea plants. These results demonstrate that soil deficiencies in N and P can be corrected by application of NPKS 25:5:5:5. However, regular checks on soil K levels are necessary when using NPKS 25:5:5:5, as this may trigger K deficiency. The deficiency can be corrected by remedial K application. The levels of the nutrients varied (p≤0.05) with location of tea production. However, levels were optimal for tea production. The variations in the macronutrients with location of production demonstrate that it may be difficult to set soil nutrients norms to guide fertiliser use advisory systems
Effect of Nitrogen and Zinc Fertilizer Application on Growth and Yield of Rice (Oryza sativa L.)
No full textNitrogen (N) and zinc (Zn) are critical nutrients that often limit yield in flooded rice systems. To investigate the effects of varying N and Zn fertilizer rates on the growth, yield, and nutrient use efficiency of rice (Oryza sativa L. cv. Sinthuka) during both dry and wet seasons through pot experiments conducted at the Yezin Agricultural University farm. The experiment was designed as a 4×3 factorial arrangement with three replications, evaluating four nitrogen application rates (0, 40, 80, and 120 kg ha⁻¹) and three zinc application rates (0, 10, and 20 kg ha⁻¹). Nitrogen application significantly enhanced plant height, tiller number, and grain yield. While the maximum grain yield was achieved at 120 kg N ha⁻¹ during the dry season, no statistically significant differences were observed between 120 kg N ha⁻¹ and 80 kg N ha⁻¹ across key growth and yield parameters, indicating that 80 kg N ha⁻¹ is likely the optimal rate for sustainable productivity in both seasons. Zinc application at 10 kg ha⁻¹ significantly increased filled grain percentages (71.20% compared to 61.97% in the control) and exhibited a synergistic interaction with nitrogen, further enhancing grain yield. The highest yields were recorded with 120 kg N ha⁻¹ combined with 10 kg Zn ha⁻¹ (71.05 g hill⁻¹) in the dry season and 80 kg N ha⁻¹ combined with 10 kg Zn ha⁻¹ (43.43 g hill⁻¹) in the wet season. Therefore, the application of 80 kg N ha-1 and 10 kg Zn ha-1 might be the appropriate rate to maximize the rice production. Considering the increased grain yield of rice, nitrogen rate 80 kg N ha-1 and zinc rate 10 kg Zn ha-1 should be used in this study area
Socioeconomic Drivers Influencing Performance of Soil and Water Conservation Measures in Tigray, Northern Ethiopia
No full textDiverse soil and water conservation (SWC) interventions were implemented in Tigray region to retard and stop soil loss due to water erosion problem. The aim of study was to evaluate the biophysical and socioeconomic drivers for the performance of implemented SWC structures under different landforms at Adi-Kimbro Watershed found in the midland agro-climatic zone of North Western Tigray. Slope, soil sample and length of destructed SWC structures were collected from plot sample size of 2500 m2 along upper, middle, foot and bottom landforms of the Watershed from different land uses. socioeconomic drivers were collected from 113 households through semi-structured questionnaires. Descriptive statistics, Pearson correlation, logistic model and independent t-test, analysis were developed. The major SWC structures implemented in both exclosures and grazing land were hillside terraces, hillside terraces with trenches, loose stone check dams and trenches. Stone bunds, check dams (cement, gabion) and \u27daget\u27 were constructed at cultivated land. Check dams at the bottom part of the watershed were comparatively effective in, rehabilitating degraded area and soil grasp. The farm size, sex household head, availability of labor and training were positive and significantly influenced the performance of SWC structures. Home distance to farm land, age and livestock holding number negatively affected to the success of the implemented SWC structures. Emphasis should be given to community participation during planning, designing, implementation and monitoring and evaluation phases by considering the household head age, labor availability, farm size, level of training, household sex and to increase the performance of SWC structures
Soil Fertility Assessment and Mapping of Gauradaha Municipality, Jhapa, Nepal
No full textThe study was conducted to determine the soil fertility status and prepare the soil map of Gauradaha municipality using tools like GIS and GPS. Altogether 101 samples were collected from 9 different wards of the municipality randomly using a soil auger from a depth of 0-20 cm. The location of the samples was recorded using MWater software. Soil texture, soil pH, available nitrogen, phosphorus (P2O5), and potassium (K2O) status of the samples were analyzed at the Agricultural Branch of Gauradaha municipality in coordination with the Agriculture Knowledge Center (AKC), Jhapa, following standard procedures. The soil map of observed parameters was prepared through the ArcGIS 10.8.2 software. The obtained data displayed that the maximum soil samples were sandy loam in texture, whereas only a few samples were found to be loamy. The soil was acidic, with pH ranging from 5.3 to 6.8 with a mean of 5.99. Available nitrogen was entirely low throughout the municipality. The study showed that 44.55%, 35.64% and 19.80% of soil samples were low, medium and high in phosphorus content respectively, which implies maximum soil samples were low in phosphorus content. Also, 17.82%, 22.77% and 59.40% soil samples were low, medium and high in potassium content respectively which implies that potassium content in maximum soil samples was high. To improve the potentiality of crops for the studied area, future research strategies should be made based on its soil fertility status
Effects of Organic and Bio-organic Fertilizer Applications on Cotton Yield and Soil Health in Saline-Alkaline and Compacted Soils
No full textSoil salinity, alkalinity, and compaction are important constraints limiting cotton production in arid and semiarid regions. This review aims to assess the potential of organic and bio-organic fertilizers to mitigate these challenges and improve soil health and crop yields. The study synthesizes findings from recent experimental and field studies conducted in saline-alkaline soils, with a particular emphasis on cotton-growing regions. Bio-organic fertilizers, consisting of farmyard manure, compost, biochar, microbial inoculants, and humate-based amendments, have been shown to improve soil structure by reducing bulk density and compaction, increase water-holding capacity, and regulate salinity and pH. These amendments significantly increased soil organic matter and macronutrient levels (N, P, K), while promoting microbial activity and nutrient cycling. Results from previous studies have shown increases in cotton yields of up to 50%, with the most consistent benefits observed when bio-organic fertilizers were combined with conservation tillage and chemical fertilizer inputs were reduced by approximately 60%. Overall, integrating organic fertilizers into cotton production systems offers an effective and sustainable strategy to address soil degradation in arid environments
Grain Yield Response of Bread Wheat to Sulfur and Phosphorus as Sole-nutrients and Interacting with Nitrogen in Four Soil Types in Ethiopia
No full textDespite sulfur being widely deficient in arable-soils, its integration into Ethiopian crop-production systems is relatively recent. This study involved six field experiments designed to evaluate the response of bread-wheat to sulfur and phosphorus (S&P) applied individually and in combination with nitrogen (N). Eight-treatments involving S, P, and N were arranged in a RCBD with three-replications, using a nutrient-omission approach. Results indicated no significant grain-yield (GY) response to the application of S or P as sole-nutrients, nor to their combinations. In contrast, the response to sole-N was highly-significant (P≤ 0.001), with GY increases ranging between 160.8–279.7%, explaining about 75% of the observed yield-variation. Wheat showed a limited response to P, even in combination with other nutrients. However, a highly significant positive interactions were observed for N×S, N×P, and N×S×P, with decreasing levels of statistical-significance. Notably, P appeared to have a suppressive effect when included in nutrient-mixes, as the GY gains from N×P were commensurate to those from N×S×P. Although phosphorus is generally recognized as critical for crop-productivity, wheat responded positively to applied P in only one-third of the experimental sites. This limited response is likely be due to the high P-fixing capacity of the soils studied, viz. Andosols, Nitisols, and Vertisols. Consequently, P inaccessibility appears to be a key factor limiting yield (with a maximum observed yield of only 6.1 t/ha), which is significantly below the wheat crop’s potential. Soil pH, rather than soil-type, emerged as the dominant factor influencing P availability and retention. In contrast, the wheat response to applied S was mainly determined by the adequacy of available or applied N. These findings underscore the complex interplay among S, P, and N in wheat production systems. However, these, and the potential role of S impurities in triple-superphosphate fertilizers, particularly in relation to wheat quality and other yield-components, warrants further investigation
Nano Calcium Preparation from Eggshell: Effects on Peanut Productivity and the Nutrient Status of Plant and Soil
No full textThrough the utilization of technology that is both cost-effective and efficient, agricultural by-products have been repurposed to produce specific chemicals, hence increasing their utilization. The purpose of this study is to synthesize and characterize nano calcium (CaO), which is produced from eggshell, along with different forms derived from it. X-ray diffraction (XRD) and particle size analysis (PSA) were employed to characterize the nano calcium that was created from eggshell. These nanomaterials were tested on peanut plants. A field experiment utilizing a split-plot design with three replications was conducted at the Ismailia Agriculture Research Station in Ismailia during the summer of 2021 to evaluate the effects of various nano calcium forms (calcium oxide, calcium acetate, calcium nitrate, and calcium phosphate) as main plots on peanut production and certain soil chemical properties in comparison to the control (gypsum). Nano-calcium and its various forms were administered at two concentrations, 1.5 and 3 g L⁻¹ as foliar application, in sub-main plots. The experiment\u27s findings showed that the peanut plant\u27s growth parameters (yield, straw, pod, and seed) rose considerably, as well as total N, P, K, and Ca content, when compared to the control. Calcium phosphates showed the highest mean value increase in crop productivity. The corresponding percentages for biological, straw, pod, and seed output of peanut plants were 30, 31, 24, and 32%, respectively. Furthermore, various forms and rates of nano calcium applications had a favorable effect on the chemical characteristics of soil; in particular, calcium acetate at 3 g L⁻¹ decreased soil pH and raised EC, OM, and accessible NPK. Also, when the rate of nano calcium administration increased, accessible calcium, soluble calcium, and exchangeable calcium typically increased. In summary, recycling organic waste can improve plant productivity and soil fertility, thereby diminishing reliance on synthetic fertilizers. Research shows that there is little difference in how well calcium treatments work, meaning that gypsum can be replaced with other calcium sources like nano calcium oxide, nano calcium nitrate, nano calcium acetate, and nano calcium phosphate. Also, this research has some environmental benefit such as waste management and reduced chemical inputs in agriculture
Nitrogenous Fertilizer Application Rates and Plucking Intervals in East Africa Tea: Effects on Soil Micro-Nutrients (Al, Fe, Cu, Zn)
No full textDepletion of nutrients are high in Eastern Africa tea soil due to high rainfall causing surface run-off and leaching, together with removal with crop. Nutrients Replenishment of nutrients by applying fertilizer is therefore necessary. However, nitrogen fertilizers may cause micro nutrients imbalance. Varying plucking intervals lead to changes in tea yields and quality. Despite varying tea growing conditions in Eastern Africa, recommended nitrogen fertilizer rates and plucking intervals are similar. Nitrogen fertilizer and plucking intervals may influence soil micro nutrients levels in different locations to varying degrees. This study determined effects of plucking intervals and NPKS 25:5:5:5 fertilizer rates on soil micro nutrients (Al, Fe, Cu, Zn) levels in different locations within Eastern Africa. Soil samples were collected from fertilizer trials on clone TRFK 6/8 at Timbilil, Changoi, Arroket (Kenya), Maruku, Katoke (Tanzania), Kitabi and Mulindi (Rwanda), from a 5x3 factorial with five nitrogen fertilizer rates (0, 75, 150, 225 and 300KgN/ha/year) and three plucking intervals (7, 14 and 21 days) as treatments at each site. Plucking intervals had no influence on the soil micro nutrients. Application of higher rates of nitrogen increased (p≤0.05) soil Al, Fe, and Cu levels but reduced (p≤0.05) soil Zn. The levels of soil micro-nutrients changed (p≤0.05) from location to location. However, the levels were adequate and did not constrain tea productivity