Journal of Tropical Soils publishes three times a year in January, May and September. Articles are written in English. Print ISSN 0852-257X, online ISSN 2086-6682. Formerly, the name of the journal was Jurnal TANAH TROPIKA (Journal of Tropical Soils) and then became online as Journal of Tropical Soils. Journal of Tropical Soils is published by Departement of Soil Science University of Lampung. Journal of Tropical Soils publishes the original research of soil science (soil physic and soil conservation, soil mineralogy, soil chemistry and soil fertility, soil biochemistry, soil genesis and soil classification, soil survey and land evaluation, land development, environment management), and related subjects in which using soil from tropical areas. The journal particularly encourages interdisciplinary research that integrates soil science with agronomy, ecology, environmental science, and land use planning in tropical settings. Journal of Tropical Soils is indexed by Google Scholar and ISJD (INDONESIAN SCIENTIFIC JOURNAL DATABASE); registered in and indexed by DOAJ (Directory of Open Access Journals), Academic Journals Database, crossref member since 2009 (crossref.org), and EBSCO PUBLISHING since 2013, SINTA, and accredited B by Directorate General of Higher Education of Indonesia (DIKTI), SK No. 200/M/KPT/2020, 23 Desember 2020. Parent DOI: 10.5400/jts. Profile in Google Scholar (Google Portal): Cited by All Since 2020 Citations 3649 2185 h-index 27 19 i10-index 130 71
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Land Suitability Evaluation for Sugarcane (Saccharum officinarum L.) Cultivation in the Rejoso Watershed, Pasuruan Regency
Land suitability evaluation is essential for optimizing crop productivity and promoting sustainable land use. In the Rejoso Watershed, Pasuruan Regency, sugarcane production remains suboptimal due to limited integration of biophysical land characteristics into cultivation management. This study aims to assess land characteristics, classify land suitability, identify limiting factors, and provide land management recommendations for sugarcane cultivation. The analysis considered key variables including temperature, rainfall, drainage, soil texture, effective depth, cation exchange capacity (CEC), base saturation, pH (H₂O), organic carbon, total nitrogen, available phosphorus (P₂O₅), available potassium (K₂O), slope, erosion risk, and flood risk. Land suitability was evaluated using a matching approach based on the Buku Pedoman Penilaian Kesesuaian Lahan Komoditas Strategis Tahun 2016. The results showed that actual land suitability consists of class S3 (Marginally Suitable) covering 22.262 ha (64.3%) and class N (Not Suitable) covering 12.342 ha (35.7%). Potential land suitability includes class S2 (Moderately Suitable) covering 8.562 ha (24.7%), class S3 covering 13.701 ha (39.6%), and class N covering 12.342 ha (35.7%). The main limiting factors identified were temperature, drainage, soil texture, effective depth, nitrogen, phosphorus, base saturation, slope, erosion risk, and flood risk. Recommended management strategies include improving drainage using the Reynoso system, applying dolomitic lime, and SP36 fertilizer. Overall, the Rejoso Watershed demonstrates substantial potential for sugarcane development through improved land management. contributing to national sugar self-sufficiency.
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Maize Nutrient Translocation on Reclaimed Gold Mining Soil with EFB Compost, Clay, and Lime
Artisanal gold mining commonly produces soils with poor fertility, low nutrient retention, and unfavorable chemical properties, which constrain crop establishment and productivity. Soil reclamation in these conditions necessitates not only improved soil quality but also effective nutrient uptake and allocation within the plant. This study aimed to evaluate the effects of oil palm empty fruit bunch (EFB) compost, clay soil, and lime on nitrogen (N), phosphorus (P), and potassium (K) concentrations in different maize organs grown on post-mining soil. Researchers conducted a pot experiment using a factorial randomized complete block design with three factors: 1) EFB compost at 6, 12, and 18 tons per hectare (t ha⁻¹); 2) clay soil at 10 and 20%; and 3) lime at 0.5 and 1 t ha⁻¹. After harvest, maize plants were separated into roots, stems, leaves, and grain, and tissue concentrations of N, P, and K were determined. The data were then analyzed using a statistical test called "ANOVA," followed by a more detailed test called "Tukey's test," which was performed at a significance level of 5%. The results showed clear organ-specific patterns of nutrient accumulation. The highest N concentration was found in the grain (1.95%), the highest P concentration in the roots (0.37%), and the highest K concentration in the leaves (3.07%), all under treatment A3B1C1. In general, the highest compost dose, when combined with clay soil and lime, consistently increased nutrient concentration across different parts of the maize plant. The findings suggest that using EFB compost, clay soil, and lime together can effectively improve nutrient availability, uptake, and partitioning in maize grown on post-mining soil. This strategy has the potential to support the productive reuse of degraded artisanal mining land.
Effect of Amendments on Soil Charge Characteristics in Sub-Optimal Dryland of Aceh Besar, Indonesia
Soil colloids play a critical role in controlling chemical behavior, particularly in tropical sub-optimal drylands dominated by variable-charge soils. However, information on the comparative effects of organic and inorganic amendments on soil charge characteristics across different soil orders remains limited. This study aimed to evaluate the effects of compost, biochar, CaCO₃, and SP-36 on the charge characteristics of tropical dryland soils. Nine amendment combinations were applied to topsoil (0–20 cm) from Andisols (Saree), Inceptisols (Cucum), and Ultisols (Jantho), followed by incubation for 60 days at 25–27 °C under field capacity conditions. Soil charge parameters were analyzed before and after incubation. Results showed that amendment type and rate significantly affected soil charge characteristics, with responses varying among soil orders. Organic amendments (15–30 t ha⁻¹) and SP-36 (2–4 t ha⁻¹) decreased pH₀ and significantly increased cation exchange capacity (CEC) and net negative charge, indicating improved soil reactivity. In contrast, CaCO₃ increased pH₀ and reduced negative charge. These findings support the strategic use of organic amendments to enhance soil fertility and sustainability.
Soil amendments, Soil colloids, Surface charge, Tropical drylands, Variable-charge soils
Change of Sandy Soil Chemical Properties with Azolla microphylla and Quail Manure
Uncontrolled land conversion reduces the available land for plant cultivation. The alternative used for rice cultivation is marginal land, such as sandy soil. However, several constraints led to very low productivity, so it needs proper management, such as adding organic matter. This study aimed to determine changes in the chemical properties of sandy soil treated with Azolla microphylla and quail manure. The pot research was carried out in the Greenhouse of the Faculty of Agriculture, Universitas Sebelas Maret, using a factorial Completely Randomized Design (CRD) with two factors. The first factor consisted of four levels of Azolla microphylla (AM),i.e., (0, 50,100, and 150 Mg ha-1). The second factor was three-level quail manure (QM ), i.e., (0, 20, 40 Mg ha-1). Fresh Azolla microphylla and quail manure were incubated for 14 days under anaerobic conditions. The results showed that applying Azolla microphylla, with or without quail manure, significantly improved the chemical properties of sandy soil. The addition of Azolla microphylla (100 Mg ha-1) with quail manure (40 Mg ha-1) increased organic C, Cation exchange capacity (CEC), available-P, Ammonium, Nitrate, exchangeable-K, Ca, electrical conductivity (EC), and redox potential (Eh).
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Modification of Peatlands Amendment with Dolomite and Fly Ash
High acidity levels and low availability of alkaline elements such as Ca, Mg, and K inhibit plant growth and reduce land productivity. This study examined the effect of dolomite and fly ash doses on the chemical properties of peatland. This study used a 2 x 3 randomized block design (RBD) factorial design with three replicates. The first factor was the type of soil conditioner, namely dolomite and fly ash. The second factor was the dose of soil conditioner, namely 5, 10, and 15 tons/ha. The effect of the type of soil ameliorant did not interact significantly with the dose of soil conditioner on pH, water content, organic C, total N, K, P, Fe, Cu, Zn, Mg, Ca, K-exch, and humate. Dolomite was superior in increasing base elements (Ca, Mg, and K) and the humification process of organic matter, while fly ash played an important role in increasing microelements (Fe, Cu, Zn) and carbon stabilization. Meanwhile, an ameliorant dose of 15 tons/ha significantly affects the increase in pH, moisture content, organic carbon, and macro nutrients (P and K). Dolomite and fly ash at an optimal dose of 15 tons/ha are recommended as a sustainable amelioration strategy to increase pH, chemical fertility, and carbon stability in peat soils without causing negative environmental impacts.
Soil Organic Carbon in Typic Hapluderts on Different Slopes and Land Uses
Organic carbon is a key component in the carbon cycle and plays a crucial role in determining soil quality. This research aimed to determine the soil organic carbon content on different slopes and land uses in Candirejo Village, Semin District, Gunungkidul Regency. Fieldwork was conducted using a survey method on Typic Hapluderts with varying slopes and land uses. Soil analyses included organic carbon, soil texture, soil bulk density, pH (H2O), and soil color. The results indicated that soil organic carbon levels varied across different slopes and land uses. Average soil organic carbon content on flat slopes was 1.64% (low), on sloping slopes it was 1.21% (low), while the land uses content from highest to lowest was in forests 2.19% (medium), in shrublands 1.55% (low), in settlements 1.31%, in dry lands 1.20% (low), and in paddy soils 0.86% (very low). Slope did not significantly influence soil organic carbon levels. However, land use significantly influences soil organic carbon levels, leading to substantial differences in soil organic carbon content. Soil color coordinate L* (lightness) is linearly negatively correlated with soil Organic-C, with a value of r = 0.641. Soil organic carbon showed a strong, significant relationship with the soil color coordinate L* (lightness). Higher soil organic carbon content was associated with lower L* values, indicating darker soil color.
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Advanced Nitrogen Management: Effects of Nano-Coated Urea on Nitrogen Leaching in Loam
Urea fertilization using controlled-release techniques is an effective way to reduce nitrogen (N) loss. One technique to decelerate N release and enhance fertilization efficiency involves applying Controlled Release Fertilizer (CRF) via Nano-Coated Urea (NCU) technology. The purpose of this study was to analyze the effect of coated urea application in reducing nitrate leaching rates and improving urea fertilization efficiency in loam soils. The materials used as urea coatings are Bentonite, which has been modified into nanosized particles. The study uses an incubation method with a lysimeter tube and destructive soil sampling to analyze soil nitrate and leached nitrate. The results showed that there was an increase in soil nitrate concentration in the LMC2 treatment (urea coating bentonite) by 28.05% and in the LMC3 treatment (urea coating nano bentonite) by 35.61%, compared to the LMC1 treatment (control urea) of 19.55%.
Model of the Relationship Between Selected Soil Physical Properties of Oil Palm Soil
Soil, water, and plants are interrelated elements in agricultural production. An in-depth understanding of the characteristics and interactions of these three aspects is essential in effective agricultural system management. The study aims to examine the relationship between soil’s water-holding capacity and different land-slope levels and to identify the physical soil characteristics that affect it. The research was conducted in a community oil palm plantation in Talang Tengah I Village, Pondok Kubang District, Central Bengkulu Regency, Bengkulu Province. The method used was a survey with purposive sampling across five slope levels: flat (0-8%), sloping (8-15%), slightly steep (15-25%), steep (25-45%), and very steep (45-100%). The data were statistically analyzed using Partial Least Squares Structural Equation Modelling (PLS-SEM) with WarpPLS 7.0. The results showed that slope had a significant effect on various soil physical characteristics and soil water holding capacity. The steeper the slope, the greater the decrease in soil permeability, total pore space, and soil organic carbon, and the greater the increase in soil volume weight, which results in a decrease in soil water holding capacity. The resulting model shows agreement in describing the relationships between variables: slope affects organic matter, sand %, and permeability, and volume weight affects total pore space and permeability, which in turn affects the soil’s capacity to hold water.
Distribution of Soil Organic Carbon along an Elevation Gradient on Kaba Volcano, Bengkulu Province, Indonesia
Climate change is a global issue largely driven by increasing atmospheric carbon dioxide levels. Many studies have focused on reducing CO2 emissions to mitigate its impacts. Volcanic soils are recognized for their high capacity to sequester carbon, second only to deep-sea reservoirs. However, limited research has examined soil organic carbon in volcanic soils on Kaba Volcano, Bengkulu, Indonesia. This study investigated the distribution of soil organic carbon along an elevation gradient on Kaba Volcano. Nine soil samples, both disturbed and undisturbed, were collected at a depth of 10 cm from three elevations: foothill, hillside, and hilltop. Undisturbed samples were taken using a 70-mm core cylinder to determine bulk density, while disturbed samples were collected with a shovel to analyze soil organic carbon, pH, and particle-size distribution. Soil organic carbon was measured using the Walkley–Black method, soil pH with a pH meter in KCl solution, and particle size using wet sieving and the pipette method. Results showed the highest soil organic carbon at the hillside, though not significantly different from the foothill, while the hilltop had the lowest content. Lower organic carbon at the hilltop may be related to drier conditions and reduced vegetation cover.
Spatial Analysis of Available and Suitable Land for Oil Palm in Ketapang Regency
Oil palm plantations are a primary sub-sector of Indonesia’s agricultural economy and continue to expand rapidly. Ketapang Regency, which has the largest oil palm plantation area in West Kalimantan, holds significant potential for further development. This study assessed land suitability for oil palm expansion using a Multi-Criteria Decision-Making approach integrated with Geographic Information Systems. The Analytical Hierarchy Process was applied to assign weights to the following criteria: slope, land cover, spatial pattern, soil texture, adequate depth, drainage, temperature, rainfall, and road accessibility. The results show that 79.56% of the total area is classified as suitable (S1 and S2), comprising 3.17% as highly suitable (S1) and 67.11% as suitable (S2). Meanwhile, 7.62% was moderately suitable (S3) and 20.44% was not suitable (N). Overlay analysis revealed that the most suitable lands overlap with Other Use Areas and Conversion Production Forests, while some intersect with existing agricultural and plantation uses. Validation with existing plantation data confirmed that 98.34% of plantations are located in S1 and S2 zones, demonstrating the robustness of the model. Overall, Ketapang Regency has substantial land availability for oil palm expansion. However, the limited extent of highly suitable land (S1) and the predominance of suitable (S2) highlight the need for cautious interpretation of expansion opportunities. Sustainable development must align with spatial regulations, land conversion policies, and environmental safeguards. Future research should integrate socio-economic, ecological, and climate change considerations to support sustainable and resilient oil palm development.
Land Evaluation and Suitability for Development of Sorghum (Sorghum Bicholor L.) on Peat Land
Sorghum is a perennial food crop that has great potential for development in Indonesia. The development of sorghum will increase land productivity, supporting the development of sustainable agriculture and enhancing Indonesian food production. The research findings establish sorghum as an ideal choice for enhancing the productivity of arid, acidic, or otherwise unproductive lands, including former mining areas reclaimed. Through the assessment of land characteristics suitable for sorghum development as a biomass energy crop in West Sumatra, Indonesia, this research endeavors to facilitate the sustainable growth of sorghum cultivation within the region. This research aims to evaluate the suitability of land for sorghum (Sorghum bicolor L.) in West Sumatra, Indonesia. Regency uses purposive sampling and survey methods. The results showed that peatland in West Sumatera, Indonesia has potential for the development of sorghum plants with average temperature characteristics 25-27 º C, rainfall <200 mm, air humidity <75%, good drainage, soil depth of peatland > 60 cm, pH 4.4 - 5.1 but low N, P and K nutrient availability.
Effect of Premium Compost on Soil Carbon Microbial Biomass in Pineapple Plants on Marginal Land Central Lampung
Acidic soil reactions, low nutrient content, low organic carbon levels, and low soil biodiversity characterize marginal land. Adding organic matter, such as compost, is expected to rehabilitate these lands. One key biological indicator of successful land rehabilitation by adding organic matter or compost is soil carbon microbial biomass (SCMB). This study aimed to assess the effect of compost on SCMB in pineapple plants. It was designed using a Randomized Completely Block Design with four treatments: Control (P0) = Without compost (Pineapple Cultivation Standard at GGPC), P1 = Cow dung compost (50 Mg ha-1), P2 = Premium compost A (50 Mg ha-1) and P3 = Premium compost B (50 Mg ha-1). Each treatment was replicated four times. The data were analyzed using ANOVA at the 5% significance level, following testing for homogeneity of variance using the Bartlett test and additivity with the Tukey test. Different treatment means were examined using contrast orthogonal tests, and correlation tests were performed to explore relationships among key variables. Results indicated that cow dung and premium compost (A and B) increased SCMB by 89.31% and 84.06%, respectively, at 15 and 16 MAP observations. At 16 MAP observations, soil organic carbon and soil pH were correlated with SCMB; in contrast, at observations 13, 14, and 15 MAP, soil organic carbon, soil pH, soil moisture, and soil temperature did not correlate with SCMB.
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Study of Soil Chemical Properties on Palm Oil Productivity in PT. Gemilang Sejahtera Abadi in East Kalimantan
East Kalimantan is a region that contributes to palm oil production. Industrial development in the area still needs to be improved in some plantations because there is a limiting palm oil productivity. This study examined the chemical properties of the soil on the PT. Gemilang Sejahtera Abadi (GSA) plantation. Observations were made in four fields with the same variety but different productivity levels. Correlation analysis and simple linear regression were used to identify factors influencing productivity. The soil on the plantation land was dominated by Typic Hapludults soil type, included in the Ultisols order. The highest productivity was found in Afdeling 1, 2, and 5, while the lowest was in Afdeling 4. The pH in each afdeling was classified as acidic, and the Organic-C, N, and base saturation contents were low. The CEC in afdeling 1 and 2 was classified as medium, while in afdelings 4 and 5 was low. All correlation analyses showed a positive relationship between the variables and palm oil productivity, with low correlation coefficients for pH, organic-C, N, P, and base saturation. The correlation coefficient between CEC and palm oil productivity has a strong relationship.
Characterization and Classification of Soils in Landslide Residual Zones to Estimate the Presence of Shallow Slip Plane
While landslide determination has traditionally relied on topography and geology, the connection between soil characteristics and landslide potential remains a relatively unexplored area. This study sets out to bridge this gap by investigating the relationship between soil properties and their classification and the likelihood of a shallow slip field triggering landslides. The research commenced with a survey of three landslide sites featuring diverse soil materials. Characterization and sampling were carried out on the residual zone left at the top of the landslide. The findings revealed that certain landslides could be identified as having potential slip planes only at a depth of 120 cm, while others could not. Two landslides in Magelang exhibited the presence of typical endopedon horizons, namely Bt (argillic). These argillic horizons serve as accumulation sites for fine and plastic clay materials. The low organic matter content also contributes to the instability and rapid dispersion of the structure. Meanwhile, the research also identified practical implications for landslide management. For instance, one of the landslides in Purworejo showed that the soil profile in the residual zone had low clay content and did not form a Bt horizon. However, the presence of shallow argillic with high clay content indicated a potential landslide risk. This finding suggests that landslides can be predicted based on soil characteristics, particularly the presence of argillic horizons. Moreover, the study identified specific soil types, such as Alfisols and Ultisols, as being prone to landslides. The Bt horizon, which can be protected by reducing erosion and runoff using silt pits, cover crops, and flow-breaking media, offers a practical solution for landslide prevention.
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Assessment of Andisol characteristics for the development of potato crops in Pangalengan
Pangalengan is a horticultural crop center area in Bandung Regency. The soil in this area consist of Andisol, which is developed from volcanic ash. One of the primary commodities in this area is potatoes. Intensive farming in Pangalengan is a problem that has an impact on soil and environmental conditions, thereby disrupting crop productivity. The research aimed to assess the characteristics of Andisols for the development of potato crop in Pangalengan. This research used qualitative, descriptive, and survey methods. The survey based on physiographic methods. Soil samples were taken purposively. The observations consisted of soil characteristics, erosion, soil fertility and land suitability. The research results show that the soil type is Typic Hapludans. Erosion is moderate (19.06-94.41 tons/ha/year) in SMU 1 and 2, high (311.22 tons/ha/year) in SMU 3 and very high (798.04 tons/ha/year) in SMU 4, soil fertility is low with land suitability for potato crop including marginally suitable (S3) and not suitable (N). Fertilization, especially P fertilizer and organic fertilizer as well as making bunds in the direction of the contour, are recommended for the development of potato crops in Pangalengan.
Spatial Analysis of Disaster Vulnerability in Wonolelo, Magelang Regency
This research aims to assess the level of disaster vulnerability in the Wonolelo tourist village area using spatial analysis with an overlay method of several factors causing disaster vulnerability. The location of Wonolelo Village on the slopes of Mount Merapi with a rather steep to steep topography makes Wonolelo Village very vulnerable to landslides and the eruption of Mount Merapi. The research results show that Wonolelo Village has a high vulnerability to volcanic disasters (63.71%) and medium vulnerability to landslides (99.12%). The findings of this research can be used to inform disaster mitigation policies and strategies in Wonolelo Village and other vulnerable areas.
Spatial Simulation of The Organic Carbon Content and its Effects on the Erodibility and Soil Erosion with Universal Soil Loss Equation and Geographic Information Systems
Universal Soil Loss Equation (USLE) and Geographical Information Systems are two spatial soil erosion analysis models because both have a spatial context. As an important factor, soil erodibility is crucial in determining soil erosion, with C-organic significantly influencing the K value. The main aim of this study is to characterize soil erodibility and soil loss based on spatial simulation of the effects of soil C-organic in a GIS environment. Research findings indicated that by simulating within a GIS environment, C-organic can affect soil erodibility and erosion. Low C-organic levels can increase soil erodibility, while high C-organic levels can decrease it. A reduction in C-organic by 10%, 20%, and 30% will increase K by 1.10%, 1.17%, and 1.21%, respectively. Conversely, adding 10%, 20%, and 30% C-organic will decrease K by 1.12%, 1.27%, and 1.46%, respectively. A 10%, 20%, and 30% increase in C-organic can reduce soil loss by 1.2%, 1.3%, and 1.5%, while a reduction in C-organic will increase soil loss by 1.1%, 1.2%, and 1.3%, respectively. A low K value indicates slight erosion, while a high K value suggests high erosion. Continuous C-organic and properly managing vegetation are necessary to maintain and improve soil quality.
The Influence of Organic and Inorganic Amendments on Phosphorus Chemistry in Two Acidic Soils of Southwestern Ghana
A study in southwestern Ghana compared the effects of organic and inorganic additives on P availability and related factors in two acidic soils, Ankasa and Abenia. Different amounts of P as KH2PO4 were applied: 0.067 g kg-1 for Abenia and 0.041 g kg-1 for Ankasa. Soil samples were treated with cow dung, Chromolaena odorata, and poultry droppings for six weeks to increase standard P requirement and neutralize exchangeable Aluminum. Data analysis was performed using GenStat (version 14). An analysis of variance (ANOVA) was conducted for the soil amendments, followed by Tukey’s comparison test at a 5% significance level to identify significant differences among the soil amendments. The result showed that higher rates of organic amendments significantly increased pH, available P (Bray 1 and NaHCO3-P), NaOH-P, and reduced exchangeable Al concentration. Poultry droppings and cow dung impact notably improved soil quality. At the same time, CaCO3 had similar effects on soil pH. However, it did not significantly affect P availability or NaOH-extractable P. CaSO4 and CaCO3 had minimal impact on phosphorus distribution, suggesting that altering pH or exchangeable Al does not necessarily change P fractions. Poultry droppings, rich in P, could be a potential alternative to lime in enhancing P availability and reducing soil acidity.
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The Isothermal Phosphate Adsorption in a New Tidal Rice Field of Barito Kuala Regency South Kalimantan: A Study on Phosphorus Adsorption in Acid Sulfate Soils for Agricultural Improvement
High P adsorption reduces rice production, especially in newly reclaimed paddy fields. The research studied soil P adsorption using the adsorption isoterm equation and soil P solubility in a New Tidal Rice Field of Barito Kuala Regency. This incubation study used soil samples from Ray 7, Balandean Village, Alalak District, Barito Kuala Regency, South Kalimantan Province, from May to November 2022. The isothermal adsorption of P was measured in six soil samples with three replicates. P (0, 2, 5, 10, 15, 30, and 50 mg P kg-1) from KH2PO4 were added in 1 g soil in 25 mL 0.01 M CaCl2. The suspensions were shaken at 25 ! for 17 hours, then centrifuged at 3000 rpm for five minutes, and the supernatant was filtered (Whatman 42) for P analysis. Three ordinary adsorption isotherm equations, Langmuir, Freundlich, and Brunauer-Emmett-Teller (BET), were used to fit the data. After adding 50 mg P kg-1, the average dissolved-P was 34.60 mg kg-1 (69%), and adsorbed-P was 15.40 mg kg-1 (31%). The BET equation was more suitable for describing P adsorption isotherm in this type of soil, which has the ability to adsorb one-third of any P addition.
The soil available P, Plant P uptake, Growth, and yield of corn in Regosol Soil Treated with Ela Sago Compost and SP-36 Fertilizer
The research examined the effect of ela sago compost on the soil chemical properties, growth, P-uptake, and yields of corn plants (Zea mays L) in Regosol soils. A randomized block design with a 2 x 4 factorial treatment was applied. The first factor was ela sago compost (B) with three dose levels: B0 = 0-Mg ha-1, B1 = 10-Mg ha-1, and B2 = 20-Mg ha-1. The second factor was SP-36 (P) fertilizer with four dose levels: P0 = 0 kg P ha-1, P1 = 60 kg P ha-1, P2 = 120 kg P ha-1, and P3 = 180 kg P ha-1. This research shows that either ela sago compost or SP-36 fertilizer can increase the soil reaction (pH). Applying sago palm compost and SP-36 fertilizer increases soil available P from 17.33 to 60.67 ppm. Applying sago palm compost and SP-36 fertilizer increases plant P-uptake from 0.18 to 0.40 %, plant height from 135.60 to 189.67 cm, and stem diameter from 1.86 to 3.44 cm, and corn yield (dry weight of 1000 seeds) from 266.60 to 390.57 g.
Study of the Quality of Biogeotextile Materials as Semi-Organic Mulch on Saline Land
Degraded land affects almost all ecosystems and can harm the progress and quality of human life, so it needs attention. Saline soil is a land degradation with high salt content that causes toxic effects, increases root osmotic pressure, and inhibits plant growth. One solution is using organic mulch processed into biogeotextiles because it can provide solutions for erosion control and soil stabilization while minimizing negative impacts on the ecosystem. This research was conducted from May to August 2023 in the experimental garden of the Faculty of Agriculture UPN ‘Veteran’ East Java. This study used a group randomized design with one factor, the type of geotextile material consisting of reed grass (RG), straw (ST), pandanus odorifer (PO), and sugarcane bagasse (SB). This research was conducted with a litterbox of 20x20 cm filled with 100 g of biogeotextile material. The results obtained show that pandanus odorifer biogeotextile material is the best biogeotextile material because it can last a long time on the soil surface, but can still be adequately mineralized, according to the results obtained, reducing the C/N ratio and C-Organic but increasing total nitrogen. Decomposition is closely related to the materials’ quality rather than external factors. The quality of the material, namely lignin, organic carbon, C/N ratio, and nitrogen, influences the decomposition process. Furthermore, this technology can be applied to improve soil productivity and to keep soil healthy.
Water Table Control Model for Maize Cultivation of C Typology Land on Tidal Lowland Reclaimed Area of South Sumatra, Indonesia
Tidal lowland productivity in type C is still low. Most of them have only been able to cultivate rice twice a year. The third cultivation of corn often fails due to a lack of water. The research objective is to determine an operational model for water management in the field for maize cultivation at several planting times. Model area is conducted at a tertiary block of reclaimed tidal lowland, Telang Jaya Village Primer 8 Delta Telang I, of Banyuasin District. There are three planting times treatments: the fourth week of April, the second week of June, and the first week of July, 2021. A water management model was applied to control the drainage system, in which the water level in the tertiary channel is maintained at a depth of 50 cm. When groundwater drops below 70 cm, and there is no rain, pump irrigation is provided. Results of the field experiment showed that the maize crop showed similar growth quality at each phase. Land with a planting period of June and July still requires water addition using pump irrigation. It was applied on 14th and 18th August. Moreover, the maize cultivated at the end of April did not require pump irrigation. All treatments have generally similar production with an average magnitude of 8.0 Mg ha-1. The highest production is 8.73 Mg ha-1, which is planted in the first week of July.
The Dynamics of Soil Organic Matter Fractions in Cacao-Based Agroforestry Systems
Soil degradation is an important problem affecting crop production, especially in cocoa agroforestry systems, where soil health is crucial for optimal results. However, the effect of land management on changes in soil organic matter (SOM) content is often not visible through measurements of total soil organic carbon (SOC) content. This study investigates the distribution of soil organic matter fractions across various land-use gradients and soil depths in cacao-based agroforestry landscapes in Southeast Sulawesi, Indonesia. Soil samples were collected from three villages representing different parts of a watershed and subjected to density fractionation to separate light (LF), intermediate (IF), and heavy (HF) fractions. Our results indicate that remnant forests (RF) maintain higher total SOM fractions, followed by cacao-based complex and simple agroforestry (CAF, SAF), particularly in the 0-10 cm soil depth. In contrast, annual crops (CR), exhibit the lowest SOM fractions. Standing litter and decomposition rates significantly influence the LF, while HF shows minimal variation across land-use systems, suggesting long-term stability. The LF also strongly correlates with SOC content, highlighting its responsiveness to recent organic inputs. The findings underscore the importance of diverse litter inputs and tree diversity in enhancing SOM fractions and SOC content in agroforestry systems. The study concludes that complex cacao-based agroforestry systems can effectively mimic natural forest conditions, promoting soil health. These insights provide valuable knowledge for sustainable land management practices to mitigate soil degradation and improve soil quality in cacao production systems.
Effect Application of Cellulolytic Bacteria Consortium And Palm Kernel Ash on Red Chili Plants in Peat Soil
Limited agricultural land in Indonesia makes peatland an alternative land for agricultural intensification. Peat soil has a low fertility, so applying cellulolytic bacteria and palm oil shoot ash is recommended. This study aimed to determine the effect of cellulolytic bacteria consortium and oil palm shoot ash on the growth and yield of red chilies on peat soils. The research was conducted in Empat Balai Village, Kampar. The study used a factorial in a completely randomized design (3x3) and three replications. The first factor was the cellulolytic bacteria consortium (0, 20, and 30 mL polybag-1), and the second factor was palm ash (0, 3, and 6 Mg ha-1 equivalent to 0.126 and 252 g polybag-1). The application of cellulolytic bacteria consortium and its interaction with oil palm shoot ash had no significant effect on all observed variables. While, the application of palm ashes significantly affected plant height, stem diameter, number of fruits, and fruits weight.
The Influence of Compost and Biochar on the Physico-Chemical Properties of Soil and the Growth of Tomatoes in Sub-Optimal Land
This study seeks to evaluate the effectiveness of coconut shell biochar (CB) and/or Leucaena compost (LC) as ameliorants in improving soil chemical and physical properties, as well as enhancing tomato yields. The goal is to identify the most effective combination of ameliorant formulations that can improve land quality and increase yield of tomato. The study was carried out over a 10-month period, spanning from March 2024 to December 2024. The research method used a Group Random Design, the treatments studied were: A0: no ameliorant + inorganic fertilizer as recommended; A1 : CB 15 Mg ha-1; A2 : LC 15 Mg ha-1; A3 : LC 5 Mg ha-1 + CB 10 Mg ha-1; A4 : LC 10 Mg ha-1 + CB 5 Mg ha-1. All treatments were repeated 5 times. The data obtained from this study were subjected to statistical analysis and further evaluated using the Duncan’s New Multiple Range Test (DNMRT). The findings reveal that applying coconut shell biochar and Leucaena compost, whether individually or in combination, markedly enhances the physical properties of the soil. These improvements include reduced bulk density (BD), increased soil organic matter SOM), total porosity (TP), and hydraulic conductivity (HC), as well as better pore distribution and water retention. Furthermore, these treatments resulted in an increase in both the tomato weight per plant and the fresh tomato weight per plot. The most effective combination for maximizing tomato yield was determined to be 10 Mg ha-1 of LC combined with 5 Mg ha-1 of CB.
Application of Rice-Husk Biochar to Coarse-Textured Ultisols and the Effects on Soil Fertility Indicators at Different Amendment-to-Sampling Intervals
The low fertility status of the highly weathered tropical soils offers the opportunity to study the potential and optimum application rate of biochar as an organic soil amendment, especially for the dominant coarse-textured Ultisols. Despite the relatively fast mineralisation of organics in these soils and the need to synchronise nutrient release crops critical stages of nutrient requirement, the time corresponding to peak effects of biochar remains unclear. The effects of rice-husk biochar (RHB) on the soil fertility of sandy-loam Ultisols at 0, 7.5, 15, 30, and 60 Mg ha-1 equivalents in 2-kg soils were assessed at 0, 2, 4, 8, and 12 weeks of incubation (WOI). Treatments were prepared in batches to enable concurrent sampling for all five incubation intervals. The RHB enhanced soil fertility across the incubation intervals, with optimal rates as 15 Mg ha-1 for soil pH and 30 - 60 Mg ha-1 for macronutrients availability. Relative to the its non-application, RHB increased soil pH-H2O, total N, available P, exchangeable bases, exchangeable acidity, apparent CEC and base saturation by 4-30%, 43-100%, 30-202%, 13-240%, 14-675%, 21-126% and 7-82%, respectively. Soil pH tended to decrease after, while available P progressively decreased before 8 WOI, when treatment effects were generally most pronounced. At an all-encompassing optimal rate range of 30-60 Mg ha-1, RHB could reduce soil acidity and enhance the macronutrient status of coarse-textured Ultisols over at least 12 weeks, soil fertility restoration effects of which are likely to be most pronounced around 8 weeks.
Spatial Distribution of Soil Properties and Soil Fertility Status in the Paddy Rice Field of Oransbari
Soil properties and soil fertility status of paddy rice fields are considered important factors related to the yield and production of rice; therefore it is essential to understand those properties across the farm. The objectives of this research is to quantify the soil properties and soil fertility status of paddy-rice soil and their spatial variability in Oransbari. Forty-two composite soil samples (0-30 cm) were taken across paddy rice fields and analyzed for soil chemical properties and fertility status. Geostatistical analysis and ordinary kriging interpolation methods were used to quantify soil variability and its fertility status across the farm. The results showed that total soil Nitrogen ranges from 0.11% to 0.17%), organic-C (1.47-6.94%), C/N ratio (11-47), total-P (13-99 mg 100 g-1), available-P (30-227 mg kg-1), total-K (27-54 mg 100 g-1), soil pH (5.83-6.93), base saturation (70-100%), and CEC is 30.51-51.23 me 100 g-1. The spatial variability of all soil characteristics exhibited medium and fit the stable model, except for available Phosphorus and Potassium. Most rice paddy fields in Oransbari showed high soil fertility status, which indicated that high-yield rice production can be achieved for this region, however, land management factors should be considered for sustainable land use.
Integrating Soil Properties and Vegetation Indices for Modeling Potato Productivity
Global potato production reached approximately 383 million metric tons in 2025, with Indonesia contributing around 1.22 million metric tons (0.32% of global output). However, the sustainability of Indonesia’s potato production is increasingly threatened by soil quality degradation in key growing regions. Existing predictive studies have primarily focused on soil chemical properties, with limited incorporation of remote sensing technologies. This study investigates the potential of Unmanned Aerial Vehicle (UAV) as a high-resolution, non-destructive tool for estimating potato yield using vegetation index transformations. Utilizing a split-plot experimental design across elevation gradients, we integrated soil properties with UAV-derived vegetation indices—Visible Atmospherically Resistant Index (VARI), Green Leaf Index (GLI), and Normalized Green-Red Difference Index (NGRDI). Results reveal that total nitrogen, base saturation, and bulk density significantly influence yield variability, and can be accurately estimated using NGRDI, GLI, and a modified GLI (GLI CS), respectively. A multiple linear regression model was developed to predict potato yield = 24.22 + 7.26(NGRDI) + 9.87(GLI) + 28.42(GLI CS). This research demonstrates the efficacy of UAV-based spectral analysis in improving yield-prediction models, offering a scalable, precise approach for sustainable potato cultivation. Future work should incorporate machine learning to improve model robustness and assess applicability across varied agro-ecological contexts.
From Rice to Oil Palm: the Historical Evolution of Peatland Reclamation in the Berbak Delta, Indonesia
The Berbak Delta in Jambi Province, Indonesia, underwent large-scale peatland reclamation in the 1970s as part of a transmigration program to develop rice fields. Initially, rice production averaged 3–4 tons/ha but declined to less than 1 Mg ha-1 due to the conversion of peat soils into acid sulfate soils. This decline was attributed to soil acidification from pyrite oxidation, which lowered soil pH. Currently, rice cultivation persists in areas near rivers influenced by tidal brackish water. In response to declining yields, a technological package for acid sulfate soil management was introduced, including canal water management, pH improvement, and fertilizer application. It increased rice yields to over 5 Mg ha-1 in a 100-ha pilot project in 2005. However, by 2008, farmers began shifting to oil palm plantations due to higher income potential. This study examines land-use change from rice fields to oil palm plantations and its impact on the livelihoods of communities in the Berbak Delta. Land cover change analysis from 2013 to 2023 revealed a decrease in rice fields from 58.30% to 25.79% and an increase in oil palm plantations from 15.37% to 55.70%. Oil palm cultivation has demonstrated sustainability on reclaimed acid sulfate soils, leading to economic prosperity through improved infrastructure and housing, as well as increased private vehicle ownership.
Impact of Land Use on Soil Water Retention in Inceptisols of the Upper Konto Watershed
The Upper Konto Watershed in Malang Regency is an area with various types of land use that have the potential to influence soil physical properties and soil water retention. Soil water retention is the ability of soil to absorb and retain water, which is closely related to the availability of water that plants can utilize. One of the soil types that dominate this region is inceptisol, which can face constraints in water retention, mainly when land use changes or inappropriate management practices occur. This study aims to analyze the impact of different types of land use on soil water retention characteristics in the Inceptisols of the Upper Konto watershed. The research method was conducted through field surveys and laboratory analysis. A survey was conducted on 16 Land Map Units (LMUs) derived from the overlay of land use, soil type, and slope maps. A total of 64 soil samples were collected for laboratory analysis. The observed variables included soil texture, bulk density, particle density, soil porosity, soil aggregate stability, soil organic matter, and soil water retention at pF 0, 2.5, and 4.2. The results revealed that land use types have a significant influence on soil physical properties as well as water retention characteristics. Specifically, it was found that forest land with the Udic Eutrandepts soil type had the highest water retention capability (0.39 cm3 cm-3). In comparison, dry farmland with the same soil type had the lowest water retention capability (0.06 cm3 cm-3). These findings illustrate the stark differences in the ability of soils to retain water between different land use types.
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