JOURNAL OF TROPICAL SOILS

The soil available P, Plant P uptake, Growth, and yield of corn in Regosol Soil Treated with Ela Sago Compost and SP-36 Fertilizer

Elizabeth Kaya — 2024-10-09

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.

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

Fadly Hairannoor Yusran — 2024-10-09

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 Influence of Organic and Inorganic Amendments on Phosphorus Chemistry in Two Acidic Soils of Southwestern Ghana

Owusu-Gyimah Victor — 2025-01-02

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.

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

Yagus Wijayanto — 2024-10-09

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.

Spatial Analysis of Disaster Vulnerability in Wonolelo, Magelang Regency

Nursida Arif — 2024-10-09

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.

Assessment of Andisol characteristics for the development of potato crops in Pangalengan

Ganjar Herdiansyah — 2024-10-09

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.

Characterization and Classification of Soils in Landslide Residual Zones to Estimate the Presence of Shallow Slip Plane

Amir Noviyanto — 2024-10-09

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.