Malaysian Society of Soil Science

Abstract
As nitrogen is an essential nutrient for MD2 pineapple growth as a substantial quantity of nitrogen fertilizer is required for increasing yield production. Highly weathered soils such as Oxisols are low in pH and nutrient contents partly due to leaching. Excessive use of compound chemical fertilizers causes nutrient leaching. Using biochar as a soil amendment to provide nutrients for improving soil properties, nutrient uptake, water retention and nutrient recovery efficiency could also minimize nitrate losses in the soil. A leaching study of six treatments with compound fertilizer (CF) and pineapple leaf biochar (PLB) was conducted. The treatments were as follows: T1= Control (soil only); T2= 100% CF (control); T3= 75% CF + 25% PLB; T4= 50% CF + 50% PLB; T5= 25% CF + 75% PLB; and T6= 100% PLB. Standard Procedures were in this study. The objective of the study was to determine the effects and the PLB rate that improve soil nitrogen retention. The cumulative loss of exchangeable ammonium and available nitrate for the treatment without PLB (T2= 100% CF) at 30 days of leaching was significantly higher than in the treatments with PLB (T3, T4, T5 and T6). Treatment 5 with 25% CF + 75% PLB gave the lowest mean value for both the mineral soils tested. The higher soil organic matter of PLB had a direct effect on the capacity of the soil to retain exchangeable ammonium, available nitrate, and total nitrogen (p< 0.05). The PLB combined with compound fertilizer improve nitrogen availability by up to 20% through temporary retention besides enhancing the soil chemical properties via mitigating nitrogen leaching hence, causing lower losses of NH₄⁺ and NO₃^- compared with compound fertilizer alone.

Abstract
The factor of safety for soil slopes is a crucial aspect of slope investigations, necessitating a thorough understanding of subsurface soil properties. Traditionally, borehole sampling has been employed for accurate assessment, despite its drawbacks of being costly and time-intensive. However, the emergence of electrical resistivity as a non-invasive technique presents a promising alternative. This method allows for efficient evaluation of subsurface soil properties, requiring minimal time and effort. The study aims to correlate soil properties such as bulk density, plasticity index, porosity, and degree of saturation with the electrical resistivity technique and present possible outcomes. The laboratory-scale Wenner probes method was used for the determination of electrical resistivity. The correlations obtained were analyzed using the correlation analysis method. The correlation between electrical resistivity and plasticity index showed an increased regression value of 0.33 for silty sand samples. For the relationship between resistivity and bulk density, the regression value was 0.32 for clay and silty sand soil samples combined. The correlation between electrical resistivity and porosity for all soil samples and silty sand soil showed R² values of 0.20 and 0.36 respectively. However, no relationship was found for clay soil samples while a weak relationship was found for the correlation between degree of saturation and resistivity. The correlations identified suggest that the electrical resistivity method is viable for assessing soil properties, although further comprehensive studies are needed to investigate weak relationships. The outcomes of the study may help bridge the gap in identifying geotechnical and geophysical data.

Abstract
Sufficient supply of nutrients is essential for optimum oil palm seedlings growth especially at poor fertile soils Improving nutrient use efficiency is very important to reduce the reliance on excessive use of chemical fertilizers and overcome the harmful impacts to the environment. The objective of this study was to determine the soil chemical properties and oil palm seedlings growth following the application of vetiver grass biochar (VGB) in combination with NPK fertilizer. The experiment was conducted in a greenhouse located at the Farm Unit, UiTM Sarawak Branch, from June 2022 until July 2023. Oil palm seedlings were planted in polybags filled with top soil and arranged in a randomized complete block design (RCBD) with 5 treatments and 5 replicates, each replicate consists of 8 plants, making a total of 200 experimental units. Treatments evaluated were: T0) absolute control; T1) 100% NPK; T2) 100% VGB; T3) 50% VGB + 50% NPK; and T4) 75% VGB + 25% NPK. Soil samples were collected before and after the treatments applied. Plant growth and soil analyses were carried out using standard plant and soil laboratory procedure. Plant growth and soil statistical data were analyzed using ANOVA at p < 0.05 followed by DMRT using the Statistical Analysis System (SAS, version 9.3). Soil pH, cation exchange capacity (CEC), and soil organic carbon increased significantly (p < 0.05) in treatments with T2, T3, and T4, while the highest value was observed in T2. Soil available N, available P, and available K were higher in the treatments with T1, T3, and T4, while the highest value was recorded in T4. The results of analysis of variance (ANOVA) for plant growth indicate significant difference at p < 0.05. Among all treatments, the highest value of plant height, bole diameter, leaf number, chlorophyll content, and plant dry biomass was recorded in T4 (75% VGB + 25% NPK), suggested that the treatment is able to improve the growth performance of oil palm seedlings and enhanced soil chemical properties, hence, allowing reduction of fertilizer application rate in oil palm cultivation.

Abstract
The biomass that accumulates on the forest floor and its subsequent decomposition play an important role in maintaining the productivity of different terrestrial ecosystems by constituting the main nutrient flow to the soil. The objective of the study focused on analyzing the nutrient contribution to the soil derived from the aboveground biomass of three native forest species in relict forests of the Central Peruvian Sierra with socioeconomic and environmental relevance. Using random delineation methods, soil samples were collected at 20-30 cm depth, which were subjected to physical, chemical, and biological analyses, developing the determination of a Soil Quality Index (SQI). The results highlight that forests of Polylepis racemosa and Alnus acuminata significantly exhibit a higher SQI, with values of 0.66 and 0.58, respectively, compared to Escallonia resinosa, with the forestless system being of lower quality with an SQI of 0.28. The relict forests, Dorado, Colpar, and Talhuis, presented the highest SQIs (0.53, 0.52, and 0.48), while Saño obtained the lowest SQI with 0.39, with no significant differences among them. The forests of Polylepis racemosa and Alnus acuminata showed a superior soil structure, higher organic matter content, moisture retention, and microbial biomass compared to other analyzed systems.

Abstract
Phaseolus vulgaris L (Common bean) is an essential pulse crop for smallholder farmers in sub-Saharan African countries like Ethiopia. However, crop growth, development, and production are limited by poor soil fertility due to poor soil management practices. Our study evaluated the effect of indigenous rhizobia inoculants on common bean root nodulation, and growth on the Gofta, a local common bean variety (G-2816) in Fedis District, Eastern Oromia Region in Ethiopia. The study, conducted at Haramaya University, isolated and characterised the rhizobia from the root nodule of a common bean. A total of five bacterial isolates were isolated from the root nodules of the Gofta on YEMA media after four days of incubation. All five isolates were identified as rhizobia based on authentication tests (Congo red test and catalase test). Based on morphological properties, all the isolates were round and slimy white with raised elevation and smooth surfaces indicating rhizobia. All the isolates were pink in colour in Gram's reaction and were rod-shaped indicating gram-negative bacteria. The ability of isolates to utilize alternative sources of carbon was assessed. Mannitol was found to be the best source followed by maltose, with sucrose being the least favoured for the selected isolates. Different tolerance levels were noticed for stress conditions: high or low pH; salt concentration; and temperature above ideal levels. The five isolates were able to grow in acidic media of pH 5.5, while three isolates (HURFB1, HURFN2, and HURFM3) showed weak growth in alkaline conditions of pH 9.5. However, all five isolates were able to grow well at salt concentrations of 2% and 3% NaCl, but reduced growth was noted for 3%; only one isolate (HURFB1) was tolerant to 5% salt concentration. At 45 °C temperature, only 20% of the isolates experienced good growth. The isolates were assessed for symbiotic effectiveness (SE) through greenhouse experiments. All isolates were symbiotically effective(SE) with 80% of the isolates recording a SE of >80% with the remaining 20% exhibiting a SE of 51 to 80%. They produced root nodules and the effects on nitrogen fixation were noticed by changes in growth and development features which revealed efficiency of rhizobia isolated. Common beans inoculated by native rhizobia exhibited better performance than those fed with nitrogen fertilizer. Among the selected five isolates, HURFM3 isolate showed highest symbiotic efficiency (187%) when compared with the nitrogen fed plants. In conclusion, this study confirmed the presence of indigenous rhizobia in Ethiopian soil, especially in the study site, which have the ability to nodulate the common bean more effectively and enhance crop growth and development.

Abstract
Potassium (K) is a macronutrient required by plants for energy production, enzyme activation, formation of cell wall, production of protein, and photosynthesis. However, its availability is compromised because of leaching. In mineral acid soils such as Ultisols and Oxisols, K in the soil solution is prone to leaching because of high rainfall and abundance of kaolinite clay minerals and sequioxides. As a result, these soils have low cation exchange capacity (CEC) but aluminium (Al) and iron (Fe) predominates. This problem has steered the attention to the application of amendments to increase K retention in such soils. The highly negative-charged sites of charcoal and sago bark ash can increase CEC to enhance K⁺ retention. Moreover, the alkalinity of these amendments can improve mineral acid soil pH to suppress Al and Fe toxicity in addition to improving K availability soils. The objective of this study was to optimize the retention to reduce leaching of K in a tropical mineral acid soil (Typic Paleudults) through co-application of charcoal and sago bark ash. The proportions of charcoal and sago bark ash used in this present study were varied at 20%, 40%, 60%, 80%, and 100%, but the MOP was fixed at 100% of the recommended rate. Selected soil chemical properties before and after the leaching study were determined using standard procedures. Results revealed that increasing rates of charcoal improved soil CEC, (total carbon) TC, and exchangeable K at 30 days leaching. Leaching of K was relatively high in the soil with chemical fertilizers compared with the soils with charcoal and sago bark ash despite the K source for the former coming solely from MOP. Although the increasing rate of sago bark ash had minimal effect on the soil exchangeable K, the ability of the sago bark ash to activate the functional groups of the charcoal is important to further increase maximum K buffering capacity. Therefore, the findings of this present study suggest that the optimum rates of charcoal and sago bark ash to reduce K leaching in mineral acid soils are 60% charcoal with 60% sago bark ash (6 t ha⁻¹ charcoal and 3 t ha⁻¹ sago bark ash) and 80% charcoal with 40% sago bark ash (8 t ha⁻¹ charcoal and 2 t ha⁻¹ sago bark ash), because these rates improved soil exchangeable K⁺, TC and CEC significantly, in addition minimizing soil exchangeable acidity at 30 days of leaching.

Abstract
Mango is one of the most consumed fruits in the world. At the cultivation stage of this plant, soil and plant nutrient management plays an important role for optimum growth. However, soil and plant nutrient contents of each tree may be different and influenced by tree age and may require a different management practice. Therefore, the objectives of this study were to examine the soil and plant nutrient contents of different ages of mango tree and to investigate their relationship. Soil and leaf samples were collected from Harumanis trees aged 12 and 38 years in Arau, Perlis. Soil samples were collected at a depth of 0–30 cm while the third or fourth mango leaf from the current flushes of the plant were collected as samples. The analyses for both soil and leaves were conducted following the standard practice. The results demonstrated that there was no significant difference among the measured parameters except for EC and total N in the soil, and K and Ca in the plant nutrient contents between both the ages of the trees. The translocation of N, P and Ca were significantly higher in the tree aged 12 years. Meanwhile soil and plant relationship show that soil pH and exchangeable bases (Ca, K, and Na) were highly correlated with Ca and N/Ca ratio in the tree aged 12 years while a highly negative correlation between total N and Ca was found in the tree aged 38 years. It is a concluded that, tree ages have an influence on the soil and plant and on their relationship as well.

Abstract
Plant height is a key indicator of healthy growth. Given the role of soil texture in productivity, the effects of sand, silt, and clay on the height and diameter of oil palm (OP) were investigated. In the four OP plantations, measurements of total and trunk heights and trunk diameters were taken from two OP clusters: tall and short. A Pro II Laser Rangefinder (ML921) was used to measure heights. Soil samples were subjected to particle distribution analysis using the pipette method. The data were processed using RStudio software. The t-test confirmed a significant difference in the heights between the clusters in all plantations, implying the accuracy of clustering. For total height, the tall cluster was greater than the short by 24.75%, 23.89%, 27.17%, and 27.51% in OP1, OP2, OP3, and OP4, respectively. Regression analysis established that soil texture accounted for 65.3%, 46.8%, 74.4%, and 69.6% of the total OP height in the fields, respectively. Sand showed a strong to moderate positive correlation with total and trunk heights, and a moderate negative correlation with trunk diameter. The clay correlated inconsistently with trunk diameter, while silt in the 0–30 cm layer showed a strong to moderate negative correlation with height. In conclusion, soil texture profoundly influences oil palm height, with sand grains exerting the greatest positive effect. Typical clay soil should be avoided during oil palm site selection, and the fields should be well-leveled to avoid erosion, which results in continuous clay deposition on the bottom slope.

Abstract
Ameliorants based on local resources are an alternative solution for farmers to sustainably optimise agricultural wastes in horticultural production. This study aimed to determine the effect of residual ameliorant formulation from a local resource (RAF-LR) on the chemical properties of Inceptisols and the production of green beans (Phaseolus vulgaris L.) in Kenagarian Pakan Sinayan, Banuhampu, Agam, West Sumatra. This study used a randomised complete block design (RCBD) with eight treatments and three replications, namely: A=Control; B=[Bamboo biochar(BB)+Tithonia Green Fertilizer(TGF)+Chicken Manure(CM)+Agam Compost(CA) ~10 t ha^-1]; C= [BB+TGF+CM ~10 t ha^-1]; D=[BB+TGF+CA ~10 t ha^-1]; E=[BB+CM+CA ~10 t ha^-1]; F=[TGF+CM+CA ~10 t ha^-1]; G=Farmer's Tradition(FT) [CM=1.875 t ha^-1] and H=Ministry of Agriculture Recommendations(MAR) [CM=10 t ha^-1]. The soil samples were from RAF-LR in the previous growing season through polyculture cultivation with an intercropping system between caisim and cauliflower. The effect of RAF-LR significantly affected the chemical properties of Inceptisols [pH, EC, CEC, OC, total N) and green beans production [nutrient plant (N and P) and total yield]. BB+TGF+CA (by 0.6 units pH H₂O; 0.51 units pH KCl; 0.173 dSm^-1; 0.35% SOC; 0.012% P-plant; 60.75% yield) and BB+TGF+CM (0.123 dSm^-1; 22.45 cmol(+)kg^-1; 2.19% N-Plant; 74.77% yield) had the most effect from RAF-LR compared to control. A significant positive correlation was observed between soil chemical properties of Inceptisols with green bean production due to the effect of RAF-LR. There was a positive correlation between the total N of Inceptisols and the total production of green bean plants at r = 0.410*.

Abstract
Urea is the most widely used nitrogen (N) fertilizer as it has a high N content (46%), is inexpensive, easily available, and can be conveniently stored. However, the high water-solubility and rapid hydrolysis of urea in the soil leads to much N loss. Rejected sago starch (RSS) was used to coat urea to prevent rapid release of N. A soil leaching experiment was conducted over 30 days to determine the effectiveness of RSS-coated urea in retaining soil N availability in the form of exchangeable NH₄⁺ and available NO₃^- compared with uncoated urea. The soil used in the leaching experiment was Bekenu Series (Sandy loam, Typic Paleudults). This study compared seven different treatments: soil alone (S), 5 g of uncoated urea (U), 5 g of 2% RSS-coated urea (CU1), 5 g of 3% RSS-coated urea (CU2), 5 g of 4% RSS-coated urea (CU3), 5 g of 5% RSS-coated urea (CU4), and 5 g of 6% RSS-coated urea (CU5). The RSS-coated urea (CU1, CU2, CU3, and CU4) significantly reduced N leaching due to the coating on the urea that serves as a barrier which slows down the conversion of N into NH₄⁺ and NO₃^-. Gradual released of N helps in retaining more soil exchangeable NH₄⁺ in all RSS-coated urea than uncoated urea. Optimize use of RSS-coated urea in CU1 (2% of RSS) did not only mitigates NO₃^- leaching, but it is also increasing soil TOM, TOC, total N, soil exchangeable NH₄⁺, and available NO₃^- although all the RSS-coated urea has minimal effects on soil pH.

Abstract
Soil organic matter (SOM) represents a crucial C reservoir for climate regulation and a necessary constituent for forest soil functions. Unfortunately, less attention was accorded to the alters in SOM under various stand ages and the relative significance of biotic (i.e., stand properties) and abiotic (i.e., soil physico-chemical features) parameters in the adjustment of SOM in forests. In the study, we investigated the SOM in soil layers of Acacia hybrid plantations over different age classes (young stand of 3 years, middle-aged stand of 6 years, and near-mature stand of 9 years) in the South Central Coast region of Vietnam. Characterizing forest stand features and other soil physico-chemical characteristics were also measured. The effects of the primary influence variables on SOM were explored. The results demonstrated that with the increase in stand age, the concentrations of SOM tended to increase. SOM content declined substantially with the increase in soil depth, showing a topsoil enrichment phenomenon. Stand structural and soil physico-chemical features significantly differed between the three plantation stand ages. The combined effect of stand and soil parameters explained 93% of alterations in SOM. Regarding the pure impacts, soil factors explained the most portion of shifts in SOM (41.10%). These findings illustrate the critical role of biotic and abiotic parameters in assessing the SOM concentration in A. hybrid forests across different stand ages. The results of the current study provide a deeper insight into the response of SOM to stand age and finally offer a reliable scientific basis for designing optimal organic matter management practices for the sustainable development of A. hybrid forests.

Abstract
Spent mushroom waste (SMW) is a mushroom-growing material that is left over from the harvest of various mushroom flushes. Normally SMW are left abandoned or discarded at the end of the development cycle. The handling and disposal of SMW remains one of the major environmental problems in mushroom producing countries. SMW can be used as growing medium however it is high of salinity where it will affect plant growth performance. Peat soil are capable to minimize the salinity due to acidic condition of peat. Therefore, peat soil was mixed with SMW in order to reduce the salinity of SMW. The treatments were constructed based on different ratio of SMW and peat soil which consist of 1:0 (T0), 1:1 (T1), 1:2 (T2), 2:1 (T3) and 1:3 (T4) and these treatments were arranged in Randomised Complete Block Design (RCBD), along with four replications. The medium were analysed for chemical properties such as salinity, pH, extractable phosphorus and exchangeable K, Ca, Mg content. The parameters of plant growth performance were measured such as plant height, leaves number, leaves width, branches number, roots length and plant biomass. Peat soil proved significantly able to reduce the salinity of spent mushroom waste and subsequently increased the growth parameter of spinach. However, the high ratio of SMW (T3) and high ratio of peat (T4) were reducing the plant biomass. The ratio of 1:1 (T1) and ratio 1:2 (T2) shows optimum chemical properties as well as shows good plant growth performance which these ratios can be suggested for growing medium.

Abstract
The aim of the present work is to understand the complex relationship between amino acids including glycine, alanine, 2-aminobutyric acid, leucine and methionine in natural soil and soil amended with pesticide. Soil samples were characterized using scanning electron microscopy (SEM) and X-ray diffraction technique (XRD). The soil thin layer chromatography method was used to study the adsorption behaviour and mobility of amino acids on natural soil and in soil amended with chlorpyrifos. Results found that the overall percentage change in R_f values from sample without chlorpyrifos and sample with 8 % chlorpyrifos is 37.5% for glycine (lowest molecular weight) and 10% for methionine (highest molecular weight). However, for the rest of the three amino acids, it was in the range of 14-15%. Chlorpyrifos is found to decrease the mobility of five amino acids in soil by making them more adsorbed on soil surface. Adsorption of amino acids is a key contributor for plant nutrition. In the present study, lowest mobility was found for glycine in pure soil and in soil amended with chlorpyrifos indicating maximum adsorption on soil surface. In future studies, adsorption performance of amino acids on soil can be analysed in presence of various additives. Keeping in view the significant effects of amino acids and pesticides on soil and plant health, it is estimated that this technology can be applied for further investigation in different fields of soil engineering.

Abstract
Manganese (Mn) serves as an essential micronutrient within the intricate nexus of soil-plant-microbial interactions, playing a pivotal role on various physiological processes crucial for optimal plant growth. Tan Cuong commune of Thai Nguyen province stands out as a distinctive tea production region in Vietnam, characterized by prolonged tea cultivation accompanied by intensive applications of chemical fertilizers, thereby exerting notable and discernible effects on the physicochemical properties of the soil. The objectives of this study were to investigate the distribution and fractionation of Mn in tea soils, with a specific focus on the prevailing context of soil acidification. The study involved a comprehensive analysis of six distinct Mn fractions within soil profiles under tea gardens and adjacent forested patches. The findings revealed a marked accumulation of specific Mn fractions in surface horizons, exhibiting a declining trend with increasing soil depth across the majority of the study sites. Notably, both tea and forest soils, the Entisols, in flat river plain area presented a special distribution of Mn fractions throughout the soil depth. The observed soil acidification resulting from tea cultivating practices was associated with an augmented solubility of Mn fractions that were previously inaccessible, facilitating plant absorption and contributing to leaching losses. The multifaceted interactions elucidated in this research furnish valuable insights for informed agricultural practices, thereby safeguarding the quality and productivity of tea plants amidst evolving environmental conditions.

Abstract
This study investigates the levels of naturally occurring radioactive materials (NORMs) and their associated radiation risks in soil samples from the Kesang River basin. With Naturally occurring radioactive materials (NORMs) abundant in the environment and potentially entering the food chain, understanding their distribution and impact is crucial for environmental and public health. Eighteen soil samples were collected using a handheld auger and analysed via an EDXRF spectrometer. Results revealed concentrations of 238U, 232Th, 40K, and 226Ra ranging from 4.47 to 31.91 Bq/kg, 23.74 to 45.67 Bq/kg, 39.75 to 318.94 Bq/kg, and 16.09 to 110.00 Bq/kg, respectively. These findings were benchmarked against UNSCEAR 2000 guidelines. Principal Component Analysis (PCA) facilitated data interpretation, aiding in the identification of key variables influencing radiation exposure. Assessment of radiological hazard parameters such as radium equivalent activity (Raeq), absorbed dose rate (D), annual effective dose (AED), external and internal hazard index (Hex and Hin), Gamma representative level index (Iγr), and Excess lifetime cancer risk (ELCR) revealed values lower than global averages. This underscores the importance of ongoing monitoring and mitigation efforts to ensure minimal radiation exposure. Overall, this study provides valuable insights into NORMs in the Kesang River basin, informing strategies for environmental management and public health protection.

Abstract
Understanding the spatial variability of soil properties is necessary in sustainable fruit crop production to prevent any nutrient imbalance in the soil. However, research that focuses on spatial variability of soil nutrient status in a mango orchard at different phenological stages is still lacking. Thus, this study aimed to evaluate the spatial variability of selected soil nutrients and to assess the distribution of soil nutrients at mango orchards during vegetative and flowering stages. Statistical and geostatistical analyses were used to evaluate the selected soil nutrient content at both crop growth stages. With the exception of total nitrogen, the correlation test reveals no relationship between any phenological stage and any nutrient. Significant positive relationships were found between total nitrogen and organic carbon, exchangeable calcium and exchangeable magnesium at both phenological stages, and total nitrogen and exchangeable potassium at the flowering stage. Different soil nutrient distribution patterns were revealed by geostatistical analysis based on varying nutrient ranges within the agricultural plot. The mapping of soil nutrients at the Harumanis mango farm can be utilized as a tool to assess spatial changes during the vegetative and flowering stages and support site-specific nutrient management, leading to more economical and effective use of fertilizers.

Abstract
Biochars, produced from different feedstocks, modify soils differently which in turn affect the growth of plants. To this end, comparing the characteristics of oak wood and bamboo biochars, evaluating their effect on soil properties and growth of ryegass (Lolium perenne L.) is crucial. Oak wood (WB) and bamboo biochars (BB) were used to fill pot with soil with 0.5, 1.0 and 2% levels each and control (0%) as treatment. After one week of incubation, rye grass seeds were sown in each pot and allowed to grow for 120 days in a climate controlled glass house. Characteristics of WB and BB, the amended soil quality, the shoots and roots biomass, and nutrient uptake of rye grass were measured and analyzed. Application of WB and BB increased nutrient content, organic C, soil pH, cation exchange capacity (CEC), water holding capacity (WHC), but decreased bulk density (BD) of the soil. As compared to BB, the WB had higher surface properties such as surface area, pore volume and oxygen containing functional groups which modified the soil pH, CEC, BD, WHC, and microbial biomass C of the amended soils. The BB had higher ash content and nutritional properties, thus it increased shoot and root biomass, and the uptake of nutrients in ryegrass. Due to its innate nutrient, BB enhanced plant growth more than WB. While WB improved the soil quality as it had better surface properties than BB. It is suggested that the biochar’s properties contribute in determining soil productivity.

Abstract
Land use is significantly crucial in determining the supply of soil organic carbon (organic-C), including humic substances derived from plant litter composition. In this context, the lignin content of organic matter is strongly correlated with the formation of humic substances, providing benefits for human well-being. Microclimate is also thought to have a significant relationship in the formation of humic substances, where lower temperature decelerates decomposition. Therefore, this research aimed to investigate the role of microclimate and vegetation on the formation of humic substances. A total of six types of land use, including mixed crop, coffee plantation, and vegetable field, apple plantation, pine forests, and conservation forest were evaluated for temperature, forest humidity, type of vegetation, and organic-C content of plant litter. The results showed that temperature and humidity affected the levels of humic substances. Higher temperature was found to be correlated with lower organic-C content. The type of vegetation significantly affected the quality and quantity of plant litter, influencing organic-C content and humic substances. The use of coffee plantation land showed an increase in organic-C content, which affected the formation of 1.85% humic acids, 6.90% fulvic acids, and 91.25% humin.

Abstract
Phosphorus (P) plays a crucial role in shaping nutrient cycles within terrestrial ecosystems. Understanding the fluctuations and factors influencing soil P in Acacia hybrid plantations in southern Vietnam is essential. The scarcity of comprehensive studies focusing on this specific ecosystem underscores the urgent need for further research to bridge this knowledge gap. This study aims to assess alterations in soil total phosphorus (TP) and available phosphorus (AP) levels and storage, as well as to identify the factors influencing soil TP and AP concentrations based on soil and forest stand characteristics across five different ages (2, 4, 6, 8, and 10 years old) of Acacia hybrid plantations within the Langa Forestry Company in southern Vietnam. Soil samples were collected at five different depths (0-20, 20-40, 40-60, 60-80, and 80-100 cm). The results revealed that soil TP and AP concentrations in the five stands increased with stand age, showing a significant decrease with soil depth. Soil TP and AP stocks increased from 4.78-5.35 Mg ha^-1 and from 0.12-0.50 Mg ha^-1, respectively, as the stand developed. Additionally, soil TP and AP stocks displayed noticeable aggregation in the topsoil, with over 40% of TP storage and over 50% of AP storage occurring within 0-40 cm depth. The structural equation model (SEM) suggested that both soil parameters (i.e., soil bulk density and pH) and forest stand characteristics (i.e., plant biomass) significantly influenced soil TP and AP concentrations. Mainly, soil properties parameters had a more substantial impact on soil P concentrations than forest stand features parameters. Our findings offer new insights into soil phosphorus dynamics, with significant implications for Acacia hybrid forests' protection and sustainable management.

Abstract
Major challenges in tropical agricultural soils included severe soil fertility depletion and decreased agricultural output. Soil amendments have often been applied to overcome this problem. Although this practice has been well proven, they are often applied solely to the soil which may be less effective to sustain the soil function especially under tropical conditions. Therefore, the objective of this study was to evaluate the response of maize yield to different rates of indigenous microorganism (IMO) biocompost or IMO5 integrated with rice husk biochar. The maize pot study was arranged in a completely randomized design using six levels of IMO5 rate in five replicates. These six levels of IMO5 were: 0 (T1), 0.75 (T2), 1.5 (T3), 3.0 (T4), 4.5 (T5), and 6.0 (T6) tonne ha^–1. All the cultivated maize were harvested on week 11 to measure their yield. The results show that T4 and above had a significant difference in cob biomass, the number of leaves, leaf area, and above-ground biomass due to high uptake of nutrient by plant from the soil. Although most of the parameters measured in this study did not show a significant difference, T4 showed the highest response in the most measured parameters.

Abstract
This study aimed to establish an alternative approach to determine the amount of available phosphorus (P) in soil samples by employing inductively coupled plasma optical emission spectroscopy (ICP-OES) compared to the conventional Ultraviolet-Visible Spectrophotometry (UV-Vis). The UV-Vis method based on the absorbance of the blue phosphate-molybdate complex is time-sensitive because its colour intensity is increased with time. Meanwhile, ICP-OES offers fast measurement of multielement simultaneously in a single run. The results showed that the ICP-OES method has a stronger linear correlation, r of 0.999794 than the UV-Vis method, r of 0.9996. The results of ICP-OES were also reproducible over 10 consecutive days while the calibration of the UV-Vis method on the other hand started to plateau at 60 mg/L. The t-test showed that there is no significant difference between both methods with a p-value, of 0.7289 > 0.05. The ICP-OES method was more robust than the UV-Vis method as the ICP-OES method could cover a wide range of soil sample concentrations and had better sensitivity with lower IDL (0.0913 mg/L and 0.0941 mg/L, respectively), LOD (0.1005 mg/L and 0.1044 mg/L respectively) and LOQ (0.3045 mg/L and 0.3164 mg/L respectively). The precision for both methods was comparable with a relative standard deviation (RSD) of 8% indicating that the variability of the data was relatively low. Finally, proficiency testing results using the ICP-OES method showed satisfactory outcomes. In conclusion, the ICP-OES method approach is the best replacement for the UV-Vis method for the determination of available P in soil samples.

Abstract
Water erosion of soils is an example of soil degradation problem in the mountainous areas of the Republic of Uzbekistan. The Republic of Uzbekistan is located in the Central Asian region, in the interfluve of the Amu Darya and Syr Darya rivers and has a unique combination of flat and mountainous terrains. Of the total area of the Republic (44.884 million hectares), mountains and foothills occupy an area of 13.429 million hectares (including rocky soils), which is 29.9% of the total territory. The natural conditions of the mountainous areas of Uzbekistan create a potential risk of soil erosion. Largely, the reasons for its manifestation are natural factors (rainfall, irregularity of surface relief), and anthropogenic factors (improper land use, failure to comply with the requirements for soil protection). The research aims to assess the condition of eroded soils in mountain and foothill areas based on models that consider natural factors (slope steepness and rainfall rate). During the research, the authors developed a model device for artificial sprinkling. Experiments under conditions of artificial sprinkling were conducted on soil monoliths prepared to determine soil washout at a rain rate of 2-4 mm/s, an experiment duration of 20 minutes, and a change in slope steepness by 5, 10, 15, and 20 degrees. The article presents the results of determining the time of soil washout on different slopes under conditions of artificial sprinkling, the amount of soil washed away, the time the soil began to wash out, and the depth of water penetration and wetting of the soil profile monolith.

Abstract
This study was conducted across selected forest reserves in Terengganu, namely Jambu Bongkok, Merchang, Pelagat, and Bukit Kesing, with the aim of addressing the conservation needs of endangered timber tree species, specifically within the Dipterocarpaceae family. The research emphasizes the urgent need for comprehensive data to enhance conservation strategies for Terengganu's valuable timber species. By evaluating the soil quality and its climatic current status, the project provides crucial tools for the Terengganu Forestry State Department to implement effective conservation measures. Soil quality assessments, based on Amacher et al. (2007), indicated that coarse fragment content generally does not adversely affect soil quality in the forest reserves, except for Merchang. Compaction levels were found to be very low across all reserves, consistent with the characteristics of undisturbed tropical forests. The Soil Quality Index (SQI) varied from 15.79% to 26.32%, with Jambu Bongkok exhibiting low SQI due to its sandy soil, low cation exchange capacity, and low water-holding capacity.

Abstract
Tropical forests face increasing pressure from logging activities, necessitating sustainable management practices to balance economic demands with ecological preservation. This study investigates the effectiveness of buffer zones in maintaining soil quality in logged tropical forests of Sarawak, Malaysia. We compared soil properties and calculated Tropical Soil Quality Index (TSQI) scores across three forest management conditions: natural forest, logged forest with buffer zones, and logged forest without buffer zones. Topsoil samples (0-20 cm depth) were collected from multiple plots within each condition and analyzed for pH, total carbon, total nitrogen, available phosphorus, and exchangeable cations. TSQI scores were calculated following established methods. Results showed that natural forests and logged forests with buffer zones achieved similar TSQI percentages of 50%, while logged forests without buffer zones scored significantly lower at 30%. Buffer zones effectively maintained soil pH, organic carbon, nitrogen, available phosphorus, and exchangeable cations at levels closer to those of natural forests. These findings highlight the importance of buffer zones in mitigating the negative impacts of logging on soil quality. The study provides valuable insights for forest managers and policymakers, supporting the implementation of buffer zones as a key component of sustainable tropical forest management practices. Further research is recommended to assess long-term effects and optimize buffer zone design for maximum soil conservation benefits.

Abstract
A case study of peat soil verification and assessment for RSPO certification among independent smallholders was conducted on 42 farms in Pontian and 73 farms in Batu Pahat, Johor. The total certified area for both locations is 135 hectares, with 127 hectares of the area planted with oil palm. The objectives were to verify the present peat status and to assess the selected properties of the peat soils in the area. The factors surveyed and measured were the depth of the peat layer, the peat humification degree, the soil N, P and K, soil pH, soil bulk density, ash content and estimation of soil carbon stock. Based on the field verification,6 out of 42 (14%) farms in Pontian and 23 out of 73 (32%) farms in Batu Pahat no longer belong to peat soil, with a peat layer <50cm depth. Based on both field assessments, the peat soils were acidic in nature with an average pH of 5.69+2.3; soil N, P and K have an average concentration of 9.87+23.13 mg/kg, 13.64+30.36 mg/kg and 32.42+40.58 mg/kg, respectively; soil ash content range between 0.8-91.85% with estimation of 73.36-494.25 t/ha of carbon stock and soil bulk density ranges between 0.20-0.81 g/cm. There is a significant difference in soil pH, water table and ash content in Batu Pahat and Pontian farms. In conclusion, verifying and assessing peat soil planted with oil palm is essential, as it impacts the management strategies required in the area, particularly for achieving RSPO certification.

Abstract
Carbofuran is one of the most toxic broad-spectrum and systemic N-methyl carbamate pesticides widely used worldwide as insecticides, nematicides, and acaricides for agricultural, domestic, and industrial purposes. The application of carbofuran reduces the loss of crops while simultaneously increasing crop productivity. However, the vast application can cause negative impacts on humans and the environment. This study aims to isolate and identify carbofuran-degrading bacteria isolated from agricultural sites. Isolation of bacteria was conducted using serial dilution and spread plate method. The isolated bacteria were incubated in a mineral salt medium added with carbofuran, and their growth rate was measured using a spectrophotometer at 600 nm for seven days of incubation. The isolated bacteria were identified using macroscopic and microscopic observation and further identified using the BBL Crystal System ID Kit and 16s rRNA sequencing method. As a result, the isolated bacteria were identified as Bacillus sp. strain UMTFA(D) and Pseudomonas aeruginosa strain UMTFA (C), respectively. The present study may provide a basis for the bioremediation of carbofuran-contaminated soils.

Abstract
Phosphorus (P) and potassium (K) nutrients are pivotal macro-elements influencing the growth and development of tomato plants. This research aims to compare the extraction results of P and K nutrients using 5 extraction methods and determine the optimal extraction method for tomato cultivation in Andisols and Inceptisols. Soil P and K availability analysis using 5 extraction methods (Mehlich-1, Bray-1, Morgan-Wolf, Ammonium acetate, and HCl-25%) correlated with tomato plants' relative dry biomass weight. Overall, the research findings indicate a significant and strong positive correlation between the 5 extraction methods of P and K with tomato plants in Andisols and Inceptisols (p < 0.01, r > 0.75). Based on the correlation coefficient (r), Mean Relative Error (MRE), and Root Mean Square Error (RMSE), the best extraction methods for P and K in tomatoes on Andisols are respectively Bray-1 (YP = 0.295x + 20.53, r = 0.88, MRE = 0.10, RMSE = 4.44) and HCl-25% (YK = 0.023x + 36.46, r = 0.90, MRE = 0.05, RMSE = 2.95). The best extraction methods for P and K in tomatoes on Inceptisols are respectively Bray-1 (YP = 0.353x + 28.58, r = 0.91, MRE = 0.05, RMSE = 2.59) and Mehlich-1 (YK = 0.036x + 21.17, r = 0.95, MRE = 0.05, RMSE = 1.84). The outcomes of this study will be instrumental in determining phosphorus and potassium fertilizer dosages for tomato plants in Andisols and Inceptisols.

Abstract
In coastal Odisha, farmers are using brackish water irrigation for different crops during rabi season due to lack of good quality irrigation water. This leads to develop salinity which is a serious threat to crop causing osmotic stress and ion toxicity. The objective of the pot study was to evaluate the beneficial effect of K, Zn, Gypsum and FYM on reduction of soil salinity and improvement in maize yield. The crop received three levels of irrigation (SW₀- normal water EC 0.5 dS m^-1, SW₁- brackish water EC 8 dS m^-1 and SW₂- brackish water EC 12 dS m^-1). Irrigation with SW₂ significantly (p < 0.001) increased the soil ECe from 1.66 dS m^-1 to 13.14 dS m^-1. It significantly reduced the maize biomass yield (15-31%), K Content (15%) and Zn content (5%) but increased Na content by 27-86% over SW₀. Potassium, Ca and Zn uptake was reduced by 27-40%, 11-31% and 9-33% respectively. Application of FYM, K, Zn and Gyp increased the biomass yield, nutrient content and uptake, K⁺/Na⁺ and Ca²⁺/Na⁺ ratio in maize. Soil ECe negatively correlated with biomass yield, K and Ca uptake, K⁺/Na⁺ and Ca²⁺/Na⁺ ratio in maize. The outcome of the study suggested that, brackish water up to 12 dS m^-1 combined with FYM, Gypsum, K or Zn fertilizer can be used for rabi crops in coastal saline soils.

Abstract
The objectives of this study were to determine the effects of combining nitrogen (N)-fixing bacteria and reduced nitrogen fertilizer on the growth, rice yield, and soil quality in the triple rice cultivation in the Vietnamese Mekong Delta region. The field experiment was arranged in a split-plot design, with the method of inoculating rice seeds with Gluconacetobacter diazotrophicus as the main factor and N fertilizer rates as the sub-factor. Two methods for rice seeds included: No inoculation with G. diazotrophicus (G₀) and inoculation with G. diazotrophicus (G_d). Four N fertilizer rates included: no N fertilizer (N₀), 50 kg N ha^–1 (N₅₀), 75 kg N ha^–1 (N₇₅), and 100 kg N ha^–1 (N₁₀₀). The results indicated that the combination of N-fixing bacteria and reduced N fertilizer could maintain the number of tillers, rice height, soil plant analysis development (SPAD) index, rice biomass, and grain yield (p>0.05). Additionally, the application of G. diazotrophicus or reduced N fertilizer did not significantly affect soil pH, electrical conductivity, soil organic matter, total N, and NH₄⁺-N at the harvest stage. However, combining G. diazotrophicus with reduced N fertilizer resulted in a significantly improved soil pH, soil organic matter, NH₄⁺-N, and available phosphorus compared to the treatment without G. diazotrophicus and treatment applied 100 kg N ha^–1. The findings from this research provide a foundation for further study of applying the G. diazotrophicus to rice cultivation to reduce the N fertilizer, increase rice yield, and improve soil quality.

Abstract
Soil-based probiotics (SBPs) are microorganisms originating from soil that have the potential to significantly enhance soil fertility and plant health, similar to the benefits of conventional probiotics in human and animal health. While much is known about the role of SBPs in the animal’s gut, the specific mechanisms and long-term impacts of SBPs in soil ecosystems remain underexplored. This review systematically summarizes recent research on SBPs, with a focus on lactic acid bacteria (LAB), including Lactobacillus and Bifidobacterium, and their role in soil and plant ecosystems. A comprehensive literature search was conducted using major databases, including PubMed, Web of Science, Scopus, and Google Scholar, covering the past 20 years. Out of 90 initial studies, 30 were excluded for irrelevance, and a further 60 were omitted based on selection criteria, leaving only the most relevant studies for analysis. The review highlights the multifaceted applications of SBPs in agriculture, focusing on their ability to enrich soil microbiomes, promote plant growth, and suppress pathogens. Additionally, SBPs offer sustainable alternatives in livestock feed. A comparison between SBPs and traditional probiotics underscores the unique advantages of soil-derived strains in agricultural systems. As sustainable agriculture practices grow in importance, SBPs present a natural, eco-friendly approach to improving soil health and plant resilience. Continued research is vital to fully harness the potential of SBPs, contributing to long-term soil health, sustainable farming, and global food security.

Abstract
The conversion of forest land to coffee agroforestry in the Upper Ciliwung Watershed may result in accelerated leaching and impoverishment of soil quality and decreased litterfall. This study aims to analyse the status of soil chemical fertility in coffee agroforestry in the Upper Ciliwung Watershed. This research used the field survey method with a qualitative data analysis approach. The results showed that the status of soil fertility in the aspect of soil chemistry is in the medium - very high category. For the cation exchange capacity (CEC) parameter, the values were 36.02 cmol/kg (high) in Cibulao, 25.45 cmol/kg (high) in Cikoneng, 24.46 cmol/kg (medium) in Rawa Gede, and 38.85 cmol/kg (high) in Cisuren. Furthermore, the P₂O₅ parameter values were 187.8 mg/100g (very high) in Cibulao, 38.6 mg/100g (medium) in Cikoneng, 39.2 mg/100g (medium) in Rawa Gede, and 22.6 mg/100g (medium) in Cisuren. K₂O was 610.6 mg/100g (very high) in Cibulao, 87.5 mg/100g (very high) in Cikoneng, 306.9 mg/100g (very high) in Rawa Gede, and 31.1 mg/100g (medium) in Cisuren, and C-organic was 6.00% (very high) in Cibulao, 7.59% (very high) in Cikoneng, 6.39% (very high) in Rawa Gede and 17.33% (very high) in Cisuren. The findings of this study contribute to understanding the factors maintaining good soil health and fertility under coffee agroforestry in the Upper Ciliwung Watershed, while also providing a foundation for sustainable land management and ensure a productive coffee groforestry.

Abstract
The most common soil types in Peninsular Malaysia utilized for oil palm cultivation are Ultisols and Oxisols. They are highly weathered soils with pH 4-5, containing toxic level of Al³⁺. Besides, the soils are low in CEC and having insufficient amount of Ca and/or Mg to satisfy oil palm requirement. The need to add extra Ca to sustain oil palm production is sometimes overlooked. This paper intends to justify the application of Ca-minerals regularly on Ultisols and Oxisols to maintain their fertility. In normal agricultural practices, Ca is unintentionally added via Ground Magnesium Limestone application. Increase in soil pH that followed further enhances crop growth. However, due to the large area being cultivated with oil palm, it becomes uneconomical to frequently do so. Some Ca is added into the soils during phosphate rock application. There are other sources of Ca that can be considered to get extra Ca, among which are gypsum, Mg-gypsum and wollastonite. Gypsum, if applied onto an Oxisol having high amount of hematite and goethite, not only are Ca and S added, but also its CEC and pH slightly increase. Application of Mg-gypsum is a better option as it also contributes Mg and some micronutrients (Cu and Zn). Besides adding Ca, wollastonite application on the soils slightly increases their pH. Its dissolution in soils produces silicic acid that can be taken up by the crop. This agronomic approach helps prevent or cure the outbreak of basal stem rot disease endemic in oil palm plantations.

Abstract
Symbiotic interaction between plants and arbuscular mycorrhizal fungi (AMF) are essential for nutrient availability. However, the AMF growth and performance are land use-dependent. Given the land use change history in the study area, this study investigated the impact of different land uses on AMF spore density and richness, their efficacy in phosphorus solubilization and cowpea performance. Soil samples were taken from lands cultivated with African star apple (SASR), Mango tree (MSR), forest trees (FSR), and cultivated soil (CSR) to establish a pot experiment. Results indicated that SASR significantly influenced AMF spore density, with 12.4% and 25.5% more spores compared to MSR and FSR at week 0, 25.5% and 27.5% more at week 8, and 37.9%, 31.5%, and 25.4% more compared to MSR, FSR, and CSR at week 12, respectively. Phosphorus availability in SASR at week 0 was double the average and significantly higher by 62.9%, 59.7%, and 56.5% compared to MSR, FSR, and CSR at week 12. There was a strong positive correlation (0.774**) between phosphorus, dry root weight, and grain yield weight. The influence of land use on AMF spore density and phosphorus availability revealed that SASR had the most significant effect, on cowpea performance.

Abstract
Polyvinylpyrrolidone (PVP), a water soluble polymer, affects the adsorption of non polar and uncharged amino acid on clayey-sand soil. Using varied concentration of PVP in the soil, the adsorption behavior of five amino acids, viz; glycine, alanine, 2-aminobutyric acid, leucine and methionine has been studied. In order to find out the quality of clayey-sand soil, its physicochemical properties are assessed. Five different solutions of PVP (0-4%) and 0.1 M concentration of each amino acid are prepared to carry out the study. Soil thin layer chromatography (soil-TLC) technique has been used here for monitoring the adsorption behavior of amino acid in the soil. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used for microstructural analysis of the soil. Adsorption of amino acid on the soil is enhanced with the increased concentration of PVP in the soil. Moreover, both SEM and XRD analysis are indicating towards the morphological changes in soil which shows the enhanced availability of amino acids to the soil and ultimately the nutrient content in plants. This study shows that PVP accelerates soil-amino acid interaction and hence the adsorption behavior of the soil towards amino acids. Therefore, PVP can be used as a potential soil conditioner on different soil types in order to obtain good nutrient content both in soil and plant.

Abstract
2-Chloroethylphosphonic acid is a synthetic plant growth regulator known for its versatile applications in agriculture including to enhance plant growth. As a member of the phosphonate family, its structurally similar to the well-known plant growth regulator, ethephon. The objective of this study is to determine effect of ethephon combined with phosphorus fertilizer application on growth performance of sweet corn at vegetative stage growth. The Rasau soil series exhibits varying chemical and physical properties across different depths. pH levels decrease with depth, with 0-20 cm being most favorable (pH 5.19) for crop growth, while 20-40 cm (pH 4.92) and 40-60 cm (pH 4.68) require lime addition to reach optimal pH (5.0-5.5). Phosphorus (P) concentration follows a similar trend, with higher levels at 0-20 cm (45.22 mg P kg^-1) compared to deeper layers. Increasing acidity leads to solubilization of aluminium (Al), with concentrations rising significantly at deeper depths. The results indicate that the Rasau soil series may have limited suitability for crop production due to its low nutrient content and high aluminum concentrations, emphasizing the significance of soil improvement to enhance soil fertility. Ethephon application at 134 ppm significantly influenced sweet corn growth, with higher concentrations 402 ppm inhibiting plant height but stimulating root growth at certain rates. Nutrient analysis showed increased concentrations in ethephon-treated plants, particularly in micro-nutrients. Ethephon also enhanced nutrient uptake, correlating positively with biomass dry weight. However, some nutrient interactions exhibited antagonistic effects. Overall, the study emphasizes the ethephon application could affect sweet corn growth together with root elongation which importance to improve nutrient uptake and crop productivity.

Abstract
RevoTropix Paulownia (RT-Paulownia), a fast-growing species known for its adaptability, was evaluated for growth performance on different soil types with varying fertilizer treatments. This study examines the growth and survival of RT-Paulownia saplings across three forest reserves in Sarawak: Sabal Forest Reserve (Ultisols), Sampadi Forest Reserve (Ultisols), and Sarawak Mangrove Forest Reserve (Spodosols). A randomized complete block design assessed three treatments: control (no fertilizer), chemical fertilizer, and organic fertilizer. A total of 231 trees were planted at each site, and data were collected over 20 months. Results showed that soil type and fertilizer significantly affected tree performance. Chemical fertilizer consistently improved survival and growth, with Sabal FR (Ultisols) showing the best performance. Trees treated with chemical fertilizer reached an average diameter at breast height (DBH) of 8.96 cm and a height of 763.68 cm. Conversely, untreated trees in Sampadi FR (Ultisols) experienced total mortality within 10 months, though organic fertilizer promoted better growth for surviving trees. Spodosols presented the most challenging conditions, with low survival rates across all treatments, though chemical fertilizer again yielded the highest performance. This study highlights the importance of soil type and targeted nutrient management in optimizing RT-Paulownia plantation success. Further research is recommended to explore long-term growth patterns and potential fertilizer strategies.

Abstract
Among paddy farmer’s regular practices are rice straw burning and continuous flooding system. However, these conditions have brought rice cultivation being among major methane (CH₄) contributors (9-11%). The interaction among mentioned conditions investigation in influencing CH₄ emissions are still lacking and urgently needed. Plus, the Intergovernmental Panel Climate Change (IPCC) model for CH₄ emissions prediction of flooded paddy field no address burnt rice straw management. Thus, a meta-analysis based on literature survey to establish the quantitative relationship of burnt and unburnt rice straw at varying water depth conditions on CH₄ emissions was conducted. The secondary data of about 79 previous studies were identified. The survey was performed from 554 cumulative CH₄ emissions (CE) in all continents, unincluded Antarctica, Australia and Africa continents. The established quantitative relationship was shown that 60.28% reduction in the CH₄ emissions under burnt rice straw with minimum till optimum water depth conditions than the unburnt rice straw with maximum water depth conditions. Briefly, the rice straw burning with minimum water depth conditions should be practice under controlled condition, after removing some of unburnt rice straw from the paddy field for CH₄ emissions mitigation.

Abstract
Commercial extraction of rare earth elements (REE) from ion adsorption clay (IAC) may release toxic elements and radionuclides and pollute the environment. Dicranopteris linearis is a fern species available in Malaysia and can accumulate REE and uranium (U) with greater efficiency, especially when IAC is treated with a leaching agent such as hydrolyzed humic acid (FA). This study aims to investigate the growth of D. linearis and its uptake for REE and U in an IAC treated with FA produced at pH 1 (1 % w/w FA pH 1) and pH 6 (1 % w/w FA pH 6). The results were compared with those of commercial ammonium sulfate (0.45 M NH₄)₂SO₄), and artificial rain (10 mM CaCl₂). The REE and U content were analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES). The t-test showed a significance value (p<0.05), indicating that the difference between the REE and U uptake of D. linearis with different treatments are significant. The highest Bioconcentration Factor (BCF) and Translocation Factor (TF) values for scandium (Sc) (5.29±0) were recorded when IAC was treated with FA pH 1. Treatment of IAC with FA pH 6 also allows translocation of cerium (Ce) to the shoot of D. linearis (TF= 1.96±0). A significantly higher uptake for praseodymium (Pr) and U was observed when IAC was treated with (NH₄)₂SO₄, possibly due to a greater mobilization that allows more uptake at the shoot of D. linearis. Using FA pH 6 may offer a safer alternative to (NH₄)₂SO₄ for selectively extracting Ce and lanthanum (La).