Malaysian Society of Soil Science

Abstract
Intensive farming is expanding rapidly, making organic fertilizer development vital to achieve sustainable agriculture. Thus, the purpose of this study is to understand the potential of decaying plants and industrial sewage sludge as organic soil amendments. This study was conducted from December 2019 to May 2021 in Ho Chi Minh City. Decaying plants and sewage sludge from wastewater treatment enterprises were collected. Manure and probiotics were also added according to the semi-fermentation method to develop different composting formulas. The quality of fertilizer was evaluated based on national standards. The last step was to observe the compost applications potential in improving acidic soil moisture and soil pH. The study found that the composts containing 70% plant waste + 20% cow manure + 10% dried sludge + microbial (0.25 liters/1m³) met the nutrient criteria of the Vietnamese Government on fertilizer management as follows: pH 6.7, total organic matter 31.08%; total N 2.37%; 5.67% P₂O₅, 8.97% K₂O; humic acid 2.59%; fulvic acid 1.24%; and C:N ratio 11.03. After applying the compost fertilizer (10,000 kg/ha), a significant improvement in acidic sulfate soil pH and moistureholding capacity was recorded compared to the conventional methods of farming.

Abstract
Intermittent climate change episodes since the Late Pleistocene resulted in decreasing or increasing the earth’s temperature causing the global sea levels to drop or rise accordingly. These episodes had a remarkable impact on landscape and soils in the Malay Peninsula. The peninsula is characterised by the presence of steep highlands in the central region with the rest occupied by upland undulating terrains and flat alluvial areas. Major soils in the upland regions are formed from igneous, sedimentary and metamorphic rocks ranging in age from Mesozoic to Paleozoic. Most soils developed from those rocks are classified as Ultisols or Oxisols. Both soil types are acidic in nature, having low basic cations insufficient to sustain crop production. Three levels of riverine terraces are scattered sporadically in the peninsula. The age of the sediments forming the highest terraces is 40,000 years, while the lowest terraces are found in the present flood plains. The fluvial characters of the terraces are preserved in the sediments that can be observed and studied. Marine deposits are located along the low-lying coastal plains. The alluvium is divided into clayey sediments found mainly in the West coast and the sandy ones in the East coast of the peninsula. The former contains pyrite at certain locations that produces acidity on oxidation, while the latter have very high sand content. The pyritization of the sediments took place 4,300 years ago when the sea level in the peninsula rose by 3-5 m above the present level.

Abstract
Compared to yields of 25-30 t ha^-1 per year obtained elsewhere, the annual fresh fruit bunch (FFB) yields of 11 t ha^-1 from oil palm plantations in Uganda are considered very low. Therefore, this study investigated the yield performance of oil palm progenies grown on various soil management groups (SMGs) in a large commercial plantation. A factorial randomized complete block design with two oil palm progenies planted in blocks of three replicates on six SMGs was used. Initially, the semi-detailed soil survey report of the plantation provided details about the SMGs. Rainfall records of 2012 to 2021 period were also documented. Site-specific agronomic techniques were implemented because of variations in the physicochemical sufficiency of the SMGs. Fresh fruit bunch data were collected every 10 days between 2016 and 2021 and subjected to analysis of variance using SPSS software version 20.0. Results showed that a change in the soil pH and cation exchange capacity (CEC) enhanced FFB yields across SMGs though in preceding years with uneven rainfall distribution, declines were experienced. However, the highest average yields were obtained from SMGs B (20.21 t ha^-1), and A (19.46 t ha^-1) and the lowest from Ait (18.03 t ha^-1) and Bi (17.79 t ha^-1). Also, the two progenies responded differently with the Deli × Ghana average yield being 19.98 t ha^-1 and 17.60 t ha^-1 for Guthrie D × P. Lastly, the highest average yield of 21.46 t ha^-1 was obtained in 2021 in contrast to that of 2016, which was only 16.12 t ha^-1. Therefore, site-specific agronomic techniques contributed to an increase in FFB output from the plantation in 2021. This study provides a guide tool to managers to evaluate the influence of site-specific agronomic techniques for yield enhancement in the plantation towards attaining higher profit margins.

Abstract
Mango is one of the six important fruits crops besides banana, watermelon, apple, orange, and grapes in the world. Of late, insidious fruit rot (IFR) has been of increasing concern among mango growers in Malaysia as this disease does not exhibit visible symptoms but has the potential to reduce the quality of the fruit. Therefore, the objectives of this study were to evaluate and correlate soil fertility status between mango orchards with and without the IFR incidence by comparing content of selected soil nutrients. The soil samples were collected from orchards planted with Harumanis, a mango variety, with and without IFR incidence. The samples were taken at a depth of 0–30 cm, crushed and then sieved using a 2-mm mesh size prior to laboratory analysis. The analyses followed standard practice. The results showed a significant difference between EC, total C, total N, C/N ratio, and exchangeable bases (Ca, Mg, K and Na) between the soil samples from Harumanis orchards with and without IFR incidences. Although soil nutrient content was higher than the optimal range for Harumanis cultivation in both sites, synergistic and antagonistic effects were discovered mostly in soil samples from Harumanis orchard with IFR incidence. Studies show that application of Ca and K fertilizers can suppress IFR incidence.

Abstract
Ultisols and Oxisols are the two dominant soils in the tropics. These soils are mostly infertile and have low cation exchange capacity because of their low pH (4 to 5). They are composed of kaolinite and sesquioxides which are prone to potassium (K) leaching. To make these soils arable, liming and fertilization are required. Nevertheless, this conventional practice alone does not mitigate K availability in such soils because of their low pH buffering capacity and low K adsorption capacity. The alkalinity of sago (Metroxylon sagu) bark ash and charcoal and the deprotonation of charcoal’s functional groups by the carbonates and oxides of sago bark ash have potential benefits. Due to these characteristics of sago bark ash and charcoal, they could be utilized to improve soil pH buffering capacity and K adsorption capacity to prevent the leaching of K and the pollution of water bodies. Moreover, the use of charcoal and sago bark ash to amend soils is a good way of utilizing agro-wastes sustainably. Thus, the objective of this study was to determine the effects of amending tropical acid soils with charcoal and sago bark on K sorption and pH buffering capacity. The treatments evaluated were: (i) 300 g soil only, (ii) 250 g charcoal only, (iii) 250 g sago bark ash only, (iv) 300 g soil + 15.42 g charcoal, (v) 300 g soil + 7.71 g sago bark ash, and (vi) 300 g soil + 15.42 g charcoal + 7.71 g sago bark ash. Langmuir bonding energy constant (K_L), Maximum K buffering capacity (MBC), and maximum adsorption capacity (q_max) of the soil with charcoal and sago bark ash were higher than that of soil alone. However, desorption of K was not significantly affected after application of the amendments. On the other hand, the combined use of charcoal and sago bark ash improved the soil’s pH buffering capacity in comparison to the untreated soil because of the inherently high CEC and alkalinity of these amendments. Therefore, this intervention could contribute to improving K fertilizer use and prevent environmental pollution and economical loss to farmers.

Abstract
Low pH acid sulfate soils are usually nutrient-deficient. They contain toxic metals that affect rice plants negatively. A field experiment was carried out to alleviate acidity in an acid sulfate soil for rice cultivation. In the study, rice-seedlings (variety MR219) were planted in the experimental plots treated with bio-fertilizer, ground magnesium limestone (GML) and biochar, either alone or in combination. pH of the untreated topsoil was 3.56, while the exchangeable calcium and magnesium in the topsoil was 4.13 cmol_ckg^-1, below the requirement to sustain growth and/or production of rice. Addition of bio-fertilizer slightly increased soil pH. The highest soil pH of 5.34 was observed in the plot treated with bio-fertilizer plus GML. Iron in the control plot was believed to exist in the form of Fe³⁺ (pKa 3). Due to treatment with bio-fertilizer plus GML or biochar, soil pH increased from 3.56 to a level >5. As the soil pH was approaching 4.58 (i.e., the pKa of Fe²⁺), Fe³⁺ was slowly converted to Fe²⁺. The form of iron causing toxicity to rice in the treated plots was most likely to be Fe²⁺, rather than Fe³⁺. At soil pH >5, both Fe²⁺ and Al³⁺ (the pKa is 5) were precipitated as inert hydroxides, thus, no longer causing toxicity to the rice plants. Beneficial microbes present in the bio-fertilizer helped produce growth hormones and organic acids that eventually increased nutrient uptake by rice which in turn enhanced its growth. The organic acids fixed some Fe²⁺ and Al³⁺ in the soil via chelation process. This phenomenon further reduced their toxicity to the rice plants. Application of bio-fertilizer plus GML or biochar improved soil fertility that resulted in higher rice yield. This notion is supported by the enhancement of the rice yield parameters, i.e., plant height (92.21 cm), tiller numbers (6), leaf chlorophyll content (38.14) and the number of filled grains. The use of bio-fertilizer plus GML or biochar is recommended for rice cultivation on acid sulfate soils in order to increase rice self-sufficiency level (SSL) and sustain food security in country in the long run.

Abstract
The soil is an element of the biosphere that forms the foundation for agricultural production. Agricultural practices can have a significant impact on the quality of soils, and therefore on the productivity and sustainability of agriculture. Thus, it is crucial to evaluate the impact of different crops on soil fertility and determine the most sustainable agricultural practices to maximize productivity while preserving soil quality. The present work examines the quality variability of agricultural soils due to cultivating different crops in a semi-arid zone in western Algeria. The research aims to compare the impact of three different crops (legumes, cereal and fruit tree cultivation) on the fertility of agricultural soils. To achieve this, we compared the physicochemical and biological properties of 75 soil samples distributed among three types of crops (five sampling stations of 400 m² per crop). The results show that agricultural soils in the studied areas are generally characterized by a sandy texture with differences in some physicochemical parameters, notably high moisture content and water retention in arboriculture (7,87%; 53%). Soils in cereal crops are rich in carbon (0,62 g/kg), whereas soils in legumes are rich in nitrogen (0,10 g/kg), which ensures good mineralization of organic matter (C/N: 5,15). Biological property analysis indicates that microbial biomass and its effectiveness are generally homogenous (p>0.05), with a small significant difference in basal respiration (P<0.05). The diversity of microflora (bacteria, fungi, and rhizobium) is influenced by organic matter differentiation caused by the agricultural practices used for each crop and their effects on the physicochemical properties of agricultural soils. In conclusion, this study shows that different types of crops have a significant impact on the quality of agricultural soils in a semi-arid zone in western Algeria. The results highlight the importance of considering the effects of different crops on soil properties to optimize crop yields and ensure the sustainability of agriculture in this region.

Abstract
Cadmium (Cd) is a mobile heavy metal that is highly toxic to almost all lifeforms. Urban eco-systems are susceptible to Cd contamination due to certain anthropogenic activities. Despite being recognised as an acutely toxic element, its biogeochemical behaviour is still poorly studied and understood, especially in urban ecosystems of tropical countries. Therefore, this study was undertaken to address this knowledge gap. This study was conducted at Air Hitam Sanitary Landfill (AHSL) in Puchong, Malaysia. Samples were collected from various abiotic and biotic factors representing the biogeochemical cycle, including soil, flora, arthropods, atmospheric deposition, leachates, and river water samples. Acid digestion using aqua regia was conducted to determine the total Cd concentration in all samples collected. Cd concentrations at AHSL were relatively high in all biotic and abiotic factors with the concentrations showing a range of 0.019 ppm to 1.568 ppm. The bulk of Cd contamination in the ecosystem was found to eventually end up in rivers. The average Cd concentration in the river samples exceeded several environmental guidelines. There was also evidence of Cd entering food chains via soil arthropods and plants. Thus, Cd poses a credible threat to inhabitants of tropical urban ecosystems.

Abstract
This study aimed to verify the effect of Plant Growth-Promoting Rhizobacteria (PGPR) and humic acid amendment with different N-fertilizer rates on sweet potato. The results showed that inoculation of UPMRB9 in combination with 50% fertilizer-N produced significantly higher dry matter (DM) in leaves, storage, and fibrous roots, and in the whole plant. Similar trends were observed for nitrogen use efficiency (NUE), in which 75% N+UPMB10 and 50% N+UPMRB9 treatments significantly produced higher efficiency by 44.89% and 40%, respectively. In addition, the highest OD of β-carotene, 0.71 and 0.68 mg g^-1, were observed in 50% N+UPMRB9 and 75% N+UPMB10, respectively. Sweet potato plants obtained greater NUE and N uptake when lower rates of N were used with the microbial inoculations. These findings show the ability of PGPR-HA to fix nitrogen and thereby increase N availability of soils, reducing the need to provide mineral nitrogen to crops. Thus, applying biofertilizer containing PGPR amended with humic acid could be a sustainable approach to improving the NUE and total N concentration of sweet potato plants. Higher N use efficiency will lead to savings in the amount of N fertilizer needed, thus reducing costs and promoting an eco-friendly approach at the same time.

Abstract
Industrial waste in the Sidoarjo Regency, Java, Indonesia has polluted the agricultural land around it. The high level of heavy metal pollution in these fields affects the physical, chemical, and biological characteristics of the soil and plant growth. This study aimed to examine the soil fertility index (SFI) of four agricultural plots of land around the paper, pharmaceutical, animal feed, and leather industries in the Sidoarjo region and the response of food crops to heavy metal contamination. The research was carried out in two stages, Stage (1): Evaluation of the soil fertility index (SFI) based on physical, chemical, and biological characteristics of the main soils; Stage (2): The response of rice plants and maize to heavy metal contamination. The SFI value is derived from the minimum soil chemical-physical-biological characteristic indicator values which include pH, EC, cation exchange capacity (CEC), K, Na, Ca, Mg, heavy metals (Fe, Mn, Zn, Cu, Pb, Hg, Cd) clay, and C-organic soils. The results showed that the value of the soil fertility index of agricultural land around the industries in the Sidoarjo area was low to moderate. The value of SFI is obtained through factor analysis of highly correlated soil features. The main factors determining the low value of SFI are soil pH, soil texture, and heavy metal content of Pb, Cd, Fe, and Zn. Therefore, it is not advisable to cultivate rice and corn in the region due to the significant uptake of high levels of heavy metal elements by these plants, which not only compromises their growth but also human health.

Abstract
Heavy metal contamination poses severe threats to ecosystems and human health, necessitating effective remediation strategies. Phytoremediation, which leverages plants to remove heavy metals, offers a promising solution. However, this approach remains underexplored, particularly in tropical ecosystems like Malaysia. Thus, this study examines the potential of native plant species in addressing heavy metal pollution, at Air Hitam Sanitary Landfill (AHSL). This location was selected due to it being an urban ecosystem that is susceptible to soil heavy metal contamination from municipal waste disposal and atmospheric deposition. Native plant species, namely Pueraria phaseoloides, Dicranopteris linearis, Cyperus rotundus, Acacia spp., and Melastoma malabathricum were found to grow well at AHSL, thus were selected for this study. The phytoremediation potential of these plant species were determined by calculating their translocation (TF) and bioaccumulation factors (BCF). Based on the TF and BCF values of all the plants studied, none of the plant species were potential phytoremediators. However, four plant species were identified as potential bioindicators of Cd. These species were Pueraria phaseoloides, Cyperus rotundus, Acacia spp. and Melastoma malabathricum. In conclusion, this study underscores the importance of understanding phytoremediation potential within challenging environments and its contribution to heavy metal mitigation. By investigating native plant species in AHSL, the research aids in expanding the application of phytoremediation strategies, ultimately fostering ecological restoration, and safeguarding human health.

Abstract
Tea (Camelia sinensis) is one of the most consumed beverages in the world. Research on the nutritional characteristics of tea, particularly lowland tea plantations, is limited in Malaysia. Thus, we aimed to investigate the nutritional characteristics (N, P, K, Ca, Mg, Al, Fe) and antioxidant activity of seven clonal teas (663, 2026, 2024, AT53, TV9, 1294, and 1428) planted at a tropical lowland tea plantation, Bukit Cheeding, Selangor, and their association with the soil edaphic factor. All foliar nutrient concentrations except for Ca and antioxidant activities varied significantly (p<0.05) among tea clones. Clone AT53 had the highest foliar K (1.84 ± 0.7 mg g^-1), Mg (0.80 ± 0.3 mg g^-1), Fe (12.97 ± 1.4 mg g^-1), and Al (16.61± 1.4 mg g^-1). Clone 663 had the highest P (13.76 ± 1.06 mg g^-1), and clone 2026 had the highest N (4.39 ± 0.2%). Clone 1248 had the highest antioxidant activity at 50.66 ± 3.2 μg mL^-1. Tea foliar N and P concentrations were significantly associated with the N and P of the soil. Besides, several soil nutrients were significantly intercorrelated with foliar nutrient concentrations. Results from this study may benefit growers in selecting better quality clones and managing lowland tea plantation at Bukit Cheeding, Selangor, Malaysia. Good farm management may improve the productivity and sustainability of tea plantations.

Abstract
The global sustainability of agroecosystems is severely hindered by soil erosion. Globally, agricultural production and the sustainability of natural ecosystems are at risk from soil erosion due to heavy rainfall, posing a severe threat to environmental conservation. Diverse nutrients, transferred along with sediments during detachment and transport by water, affect soil fertility and productivity. The effects of management practices and nutrient losses on soil erosion have remained undefined. A field experiment was conducted at University Research Farm, Koont Chakwal Road in the Pothwar Plateau, during the monsoon season from mid-July to mid-September, 2019 in which fallow-based cropping systems used in conservation tillage systems were compared to double cropping and green manuring systems. There were eight treatments and three replications with a split-plot arrangement design. The 900 m² plot having 3% slope was split into two major plots for the tillage treatments: conventional tillage and reduced tillage. Each main plot was then divided into four subplots for the summer crops: (i) fallow, (ii) soybean, (iii) maize fodder, and (iv) sesbania green manure. A plastic drum was installed at the bottom of each sub plot to collect runoff and sediment. The amount of sediment, nutrient concentration, and soil organic matter was collected and measured in runoff water. In contrast to cropped plots, the results showed that fallow plots had a higher rate of runoff water. Maize fodder and sesbania were among the cropping systems with the lowest sediment losses. Reduced tillage (chisel) showed less sediment loss than mouldboard plough. Overall, nutrient losses varied between crops and tillage systems. However, there was no significant difference in organic matter loss between tillage systems, but there was significant difference among crop systems with fallow plots showing the highest and maize plots having the lowest organic matter loss in different rainfall events. In conclusion, reduced tillage (chisel plough) in combination with summer crops, specifically maize fodder, can considerably reduce water erosion and soil losses in the Pothwar region.

Abstract
Rice cultivation under continuous flooding (CF) is a major anthropogenic emitter of methane gas (CH₄) due to the oxygen-deprived state of the submerged soil. The potentials of alternative irrigation regimesi.e., mid-season drainage (MD) and alternate wetting and drying (AWD) to reduce CH₄ emissions from Malaysian rice cultivation were investigated in the present study. Rice (Oryza sativa var. MR297) was transplanted into 15 tanks and randomly assigned to each of the three treatments: CF, MD and AWD in a randomized complete block design (RCBD). Emissions of CH₄ were measured weekly by collecting air samples using static chambers and analyzing the air samples for CH₄ concentration using gas chromatography (GC). The present study found that cumulative CH₄ emissions per planting cycle were 70.24, 30.75, and 15.93 g CH₄ m⁻² from treatments CF, AWD and MD, respectively. Methane emissions of the MD and AWD treatments were 77.07% and 57.81% lower, respectively, compared to CH₄ emissions of CF. The present study indicated that AWD and MD had the potential to reduce CH₄ emission in rice cultivation.

Abstract
Soil characteristics are a crucial matter in relation torice production in a swampland area. A study on chemical soil characteristics and economics of swampland rice production was carried out at a subdistrict of Rambutan and Banyuasin 1, Banyuasin, South Sumatera. Evaluation of soil organic matter in both locations foundcarbon content in Rambutan and Banyuasinto bemedium to high and medium to very high, respectively. In respect to nitrogen content, Rambutan had very low to medium, while Banyuasin 1 fell into the low to medium categories. Based on the average C/N ratio, both locations were considered to have a high accumulation of organic matter in the soil. In regard to macronutrient content, especially P and K, Rambutan and Banyuasin 1 fell into the low to medium category for P and low for K. Cost analysis of swampland rice production in both locations revealed the production processto be economically feasible. Linear regression analysis among pertinent factors in production improvement presented the positive impacts on rice productivity to be derived from Amount of planted seeds, phosphate fertilizer, return of straw to soil/organic matter and knowledge of the recommended fertilizer dosage.

Abstract
This study investigated the influence of added organic materials on glyphosate mobility through sandy loam soil. An equivalent rate of 10 t ha^-1 of either cattle dung or rice husk ash were mixed with the soil and inserted into leaching tubes Both soil mixture and controls were spiked with 20 mL of 200 mg L^-1 glyphosate. This was followed by an addition 100 mL of stimulated rainfall and the leachate collected at time intervals (0,3,10,22,32,40,50 and 65 days) for glyphosate analysis. After 65 days, soils were cut into three, dried and determined for its glyphosate residual concentration. The data obtained was analysed and results revealed no significance difference (p > 0.05) in glyphosate concentration between the treatments, at time intervals (0,3,10,22,32,40,50 and 65 days) and from residual concentration in soil after leaching. Nonetheless, an increased concentration was obtained from both cattle dung (10%) and rice husk (9%) compared with control, indicating potential influence of these wastes on glyphosate mobility. The order of cumulative glyphosate concentration from post-leaching soils was as follows: control with 17.798 μg g^-1; > soil + rice husk ash with 15.484 μg g^-1; and > soil + cattle dung with 14.918 μg g^-1. Meanwhile, irrespective of the treatments applied, the concentration of glyphosate in the soil layers were of the following order: top layer with 17.020 μg g^-1; > middle with 16.745 μg g^-1; and > lower layer with 14.436 μg g^-1. The length of each layer was about 3.3 cm, suggesting low glyphosate mobility.

Abstract
This paper aimed to obtain appropriate indigenous arbuscular mycorrhizal fungi types and determine the right dosage of phosphate fertilizer to increase rice yields under the System of Rice Intensification Cultivation. The research design used a factorial randomised block design with three replications. Factor I was a type of arbuscular mycorrhizal fungi (Glomus sp. 2, Glomus sp. 3, and Sclerocystis sp) on Agam river sand media with the number of spores being 120 spores per 100 grams of sand media. The dose of arbuscular mycorrhizal fungi was 1.6 tons/ha or 15 g/plant. Factor II was the dose of phosphate fertilizer (P = 0%, P1 = 25%, P2 = 50%, and P3 = 75%) of the recommended dose which was applied for each treatment at these rates:: P = 0 g/plot, P1 = 20 g/plot, P2 = 40 g/plot, and P3 = 60 g/plot. The data was analsed for variance using the SAS program. The results showed that Glomus sp. 3 with 50% phosphate fertilizer efficiency had statistically significant different results (p <0.05) for plant height, number of tillers, number of panicles, number of filled grains, weight of 1000 seeds, and yield per hectare compared to the other treatments. The nutrient content of paddy fields pH, CN-ratio, total N , P available and CEC showed a statistically significant difference between the arbuscular mycorrhizal fungi types and the P fertilizer efficiency treatment. No statistically significant difference was found in the CN ratio between Glomus sp. 3 and Sclerocystis sp., but there was a statistically significant difference from Glomus sp. 2.

Abstract
Despite continuous governmental initiatives, oil palm yields in Ghana is significantly lower than Southeast Asian nations, being unable to even satisfy domestic demand. It hypothesized that one of the main limiting factors to oil palm production in Ghana is due to poor soil suitability. However, there is limited soil studies in Ghana oil palm plantations. Thus, this study was conducted to evaluate the soil fertility status of smallholder oil palm plantations in the Brong Ahafo and Ashanti Regions of Ghana. By understanding the soil condition, appropriate land management strategies can be conducted to increase the productivity of Ghana’s smallholder oil palm plantations. Soil sampling was conducted in four plantations, two each in the Ashanti Region and Brong Ahafo Region, with 25 samples collected from each plantation. Samples were taken from between palm trunks, at a depth of 0-20 cm, using a soil auger. Appropriate soil analyses were conducted to determine the chemical soil properties of the samples. Additionally, the Nutrient Index was calculated to evaluate the soil’s sufficiency for crop nutrition. The soil analysis revealed differences between the regions, with Brong Ahafo exhibiting lower soil quality, particularly in organic matter and available phosphorus. Both regions displayed low Nutrient Index values, indicating inadequate soil nutrient supply for optimal crop growth. To enhance smallholder productivity and profitability, addressing knowledge gaps and providing support in land preparation, field maintenance, and fertilizer access is crucial. Government intervention and subsidies for smallholders can boost yields, meet domestic palm oil demand, and improve farmers' livelihoods in Ghana.