Department of Soil Science, Faculty of Agriculture, Universitas Gadjah Mada, Yogyakarta, Indonesia
RESEARCH, TEACHING, or OTHER INTERESTS
Soil Science, Agricultural and Biological Sciences, Ecology, Evolution, Behavior and Systematics, Environmental Science
6
Scopus Publications
Scopus Publications
Soil deterioration assessment as an indicator of land degradation in dry land ecosystems based on a multi-criteria approach, North Halmahera, Indonesia Adnan Sofyan, Tri Mulya Hartati, Lily Ishak, Krishna Aji, Gunawan Hartono, Nurul Ainun Tangge, Fitriani H. Achmad Journal of Degraded and Mining Lands Management, 2026 Land degradation is one of the biggest challenges to agricultural sustainability in tropical regions, mainly due to the pressures of land intensification, climate change, and unsustainable soil management practices. Soil deterioration can occur in physical, chemical, and biological aspects, thereby reducing the soil's capacity to support agricultural productivity. This study aimed to evaluate the status of soil deterioration through a multi-parameter approach in the dryland ecosystem of North Halmahera, Indonesia. The parameters analyzed include solum thickness, surface stoniness, fraction composition, bulk density, porosity, water permeability, pH, electrical conductivity (EC), redox potential, and microbial population. The results showed that all points experienced degradation, with four points (T1, T2, T4, T5) classified as moderately deteriorated and the other four points (T3, T6, T7, T8) classified as severely deteriorated. The main factor of deterioration was very high salinity (29-50 mS/cm), far exceeding the critical threshold, which caused osmotic stress and ion toxicity to plants, low redox (100 mV), high bulk density (1.83-1.99 g/cm³), extreme porosity (>70%), and low microbial population (<10² CFU/g) at several points. However, the soil pH is relatively neutral (6.8-7.0), so it is not a limiting factor. The results of this study are used as reference material for sustainable land management to achieve the sustainable development goals.
Morphological and Physicochemical Comparison of Sandy Soils under Horticultural Monoculture on the Erosional Slope of Gamalama Volcano, Ternate Island Malaysian Journal of Soil Science, 2025
Soil moisture monitoring for drought disaster mitigation using remote sensing on the volcanic landscape, Yogyakarta, Indonesia Tiara Sarastika, Yusuf Susena, Krishna Aji, Uli Ulfa Journal of Degraded and Mining Lands Management, 2025 Monitoring soil surface moisture is a crucial aspect of drought detection and management, significantly contributing to informed decision-making in agriculture and natural resource management. Remote sensing technologies have been widely applied to predict surface soil moisture. This study aimed to develop and analyze a surface soil moisture prediction model based on remote sensing data for drought mitigation. This research was conducted in the administrative area of Sleman Regency, Yogyakarta Special Region Province. This study employed a method that integrates field measurements with remote sensing-derived data to develop a predictive model of surface soil moisture. The model was constructed using the Extreme Gradient Boosting (XGBoost) machine learning algorithm. The modeling results yielded an R² value of 0.62 and an RMSE of 0.83. The model was then applied to generate spatial estimates of surface soil moisture for the period from May to October 2024. Spatially, all six months exhibited a consistent distribution pattern, with low soil moisture levels concentrated in the central southern part of the study area. The findings can serve as a basis for highlighting land management in line with SDG Goal 15, which aims to protect, restore, and enhance the sustainable use of terrestrial ecosystems, sustainably manage forests, halt and reverse land degradation, and halt biodiversity loss.
Distribution of soil morphology and physicochemical properties to assess the evaluation of soil fertility status using soil fertility capability classification in North Galela, Indonesia Tri Mulya Hartati, Bambang Hendro Sunarminto, Sri Nuryani Hidayah Utami, Benito Heru Purwanto, Makruf Nurudin, Krishna Aji Journal of Degraded and Mining Lands Management, 2023 One of the indicators of land productivity assessment is soil fertility. The causes of infertile soil have been widely reported. This study aimed to evaluate soil fertility using the Soil Fertility Capability Classification (SFCC) approach and to determine the relationship between soil morphological and physiochemical properties and soil fertility. The research was conducted in North Galela Sub-district, North Halmahera Regency. The research framework began with the interpretation of thematic maps, surveys, field observations, and the making of soil fertility evaluation maps. Soil sampling was carried out based on the stratified random sampling method and supported by laboratory measurements according to USDA international standards. The research result showed that the research area had 14 soil fertility statuses. The fertility classes having the most significant limiting factor were loamy texture (Ø&lt;0.002 mm), rock surface, gravel subsoil, moderate salinity (0.2-0.4 mS cm<sup>-1</sup>), low exchangeable K (&lt;20 cmol<sub>(+)</sub> kg<sup>-1</sup>), and sloping slope (8%) with Lithic Haprendolls type and loamy texture (Ø&lt;0.002 mm), subsoil &gt;15% rock outcrop, moderate salinity (0.2-0,4 mS cm<sup>-1</sup>), Na saturation &gt;15%, and a rather steep slope (14%) with Lithic Eutrudepts type. Both of these classes have a top layer texture, and the bottom layer contains clay &lt;35%, with limiting factors of hard layer inhibiting root to a depth of 50 cm, extremely low nutrient reserve, low electrical conductivity (EC) and high Na. The limiting factors found in North Galela Sub-district were hard root-restricting layer, exchangeable K, electrical conductivity, Na saturation, slope, and gravel.
Relationship between soil morphology and variability of upland degradation in Bogowonto Watershed, Central Java, Indonesia Krishna Aji, Azwar Maas, Makruf Nurudin Journal of Degraded and Mining Lands Management, 2020 Land-use change and lack of conservation in Bogowonto Watershed area have caused land degradation due to erosion and landslides. The rate of land degradation can be measured through the morphological characteristics of the soil and landscape. This study aimed to identify the relationship between the morphological characteristics of the soil and the rate of land degradation in Bogowonto Watershed area. The research framework initiated from the interpretation of thematic maps, surveys and field observations, and verification using land degradation assessment software. Sample points were determined using a stratified random sampling method. In general, land degradation is affected by slope, limited soil development, suboptimal conservation measures, and land-use change. Particularly, land degradation is affected by the type of landscape and the morphological characteristics of the soil. Volcanic hilly landscapes show a degradation rate of fine to very fine, characterized by thick soil depth (>60 cm), generous root distribution, loamy textured soil, fine soil particle size (Ø <0.002 mm), and good soil structure. The distribution of easily weathered volcanic ash causes volcanic hills to have thick and fertile soil characteristics. Quaternary-tertiary volcanic transition landscapes show a degradation rate of damaged to heavily damaged, characterized by thin soil depth (<60 cm), limited rooting, dominant coarse fraction (Ø 2–0.05 mm), and contact with fields lithological discontinuity. The data obtained provide information on the morphological characteristics of the soil and land degradation in Bogowonto Watershed area. The results of the study can also be used as a formulation for the conservation of Bogowonto Watershed area.
Process and mineralogy of volcanic materials on the south side of the old Lawu Volcano in Java Island Mohammad Nurcholis, Dwi Fitri Yudiantoro, Darban Haryanto, Ahmad Bagus Dianputra, Krishna Aji Sains Tanah, 2019 Activities of Old Lawu volcano in the past resulted in various soil development in the south side of the volcano, especially in the area of the east side of Wonogiri and west side of Ponorogo, that located in the Java island. This area is also famous as herbal crops producer for raw materials of traditional herbal medicine industry. The purpose of this research is to identify the process of exposure of the parent materials in the Old Lawu volcanic environment, the development of the soil parent materials, and the mineralogy variation. Four Sites with different geological formation were observed, and each Site was selected for soil profile identification on the process of weathering of rocks. All layers of each profile were then sampled and then sand fraction of the fine earth particle was determined for the mineral type using X-ray diffraction (XRD). The results showed that materials of the Old Lawu volcanic activity that was of quaternary period had sized material of gravel, sand, silt, and clay. These materials were then exposed and undergone the process of weathering, transportation, and sedimentation according to the landform at that period. The development of soil as geoheritage in this region was influenced by the material size, landform, and settling process. There are four typologies of the environment on the soil development at the present study, there are: (1) Soil that developed in the inter-fluvial basins is characterized by thick soil and a clear horizon differentiation process as a feature of maturity stage of soil development. (2) Soil developed on the slope of hill area is characterized by shallow in solum and it is in early-stage soil development. (3) Soil developed on the volcanic materials that were transported and sedimented in the river environment is characterized by the thick soil above the layered fine size parent material with a variety of color. (4) Soil developed on the tertiary breccia showed early soil development.
