Judul: Developing soil-landscape model to predict soil property distribution in tropical region: case study in Java Island
Abstrak: Soil property and its distribution are required as a basic input in planning, managing, and monitoring land resources as well as in assessing soil for improving crop productivity and in evaluating the impact of land use to environment. Yet, data collection consumes much money and time so that a new mapping approach is required. Some current advances in database technology, spatial mathematics, geospatial analysis, and computer technology can explore spatial pattern in legacy soil data more efficiently. A digital soil mapping makes use the available techniques and revitalizes data, but it has not been tested yet in the tropical region. This research aimed: (i) to develop soil-landscape models using legacy soil data from Java, (ii) to evaluate model transferability in other region, and (iii) to map soil property in new area using modified digital soil mapping framework based on legacy data. The research covers (i) legacy data collection and harmonization from Java Island, (ii) model development using stepwise regression and tree regression, (iii) model transferability evaluation in the Upper Cisadane Watershed in Bogor, West Java Province and in the Upper Sampean Watershed in Bondowoso, East Java Province, and (iv) soil map creation using a digital soil mapping technique in Upper Cisadane watershed. The study resulted in 96 soil-landscape models that have good predictive power to predict selected soil properties. The best model were models to predict thick of A horizon, depth to B horizon, clay percentage, pH, and cation exchange capacity. Model transferability in both watershed varied depending upon the combination of covariates and watershed characteristics. Models to predict soil depth was demonstrated to map soil depth distribution in the Upper Cisadane Watershed. The method, models, and dataset from this research could be used to assist in accelerating soil survey and mapping.
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Judul: Diversity of Soil Characteristics in Field and Its Relation with Landform Spatial Pattern at Agrotechnopark Koleberes, Cianjur
Abstrak: Soil mapping in detail scale needs a high intensity of observation and costly. To decrease the cost, the mapping usually done using an approach of delineation of soil forming factors into homogeneous sets. This approach is based on an assumption that if soil forming factors are homogeneous then the soil characteristics will also homogeneous. However various survey experiences indicated that at sloping areas, soil characteristics still vary although soil forming factors show a high homogeneity. The aim of this research is to study soil characteristics observed from boring with a high observation intensity and to search for a spatial relation between soil characteristics and classification with spatial distribution of landform at a slopping areas. Materials of this research comprised contour map, geology map, existing soil map and soil data covering profile description and its of physic and chemical data. GIS software (Arc View GIS 3.3) was used for spatial analysis of landform. In this research, landform are delineated based on an 1:1000 contour map considering the concept of “Model Diagram of Nine Land Surface” of Dalrymple et. al. (1968; in Darmawan, 1987). Field characteristics of soil were obtained from borings taken at the close distances along slope transects. Observation conducted at some slope transects across various landforms. Soils on research location formed from parent material which is relatively homogeneous under the influence of the same climate, organism and times. Meanwhile relief/ topography shows a high heterogeneity, with differences that even happened at a narrow space. This heterogeneity is reflected by existence of various landform i.e. convex-rather flat-upper slope, straight-flat to rather steep middle slope, concave-rather steep lower slope, etc. Soil field characteristics obtained from boring observation at close distances show very high variations as shown by variation in composition and depth of horizon A and B, soil colour, texture and consistency. This phenomenon could affect the soil classification at family and series level. Toposequently, from upper slope (convex) through the mid slope (straight), to the lower slope (concave) had a tendency to have more complex horizon composition. This phenomenon was due to the dominant process of erosion at the upper slope, and deposition at the lower slope.
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Judul: Katalis Zink Ferit Tersubstitusi Cu untuk Oksidasi Benzil Alkohol
Abstrak: Katalis berperan dalam menurunkan energi aktivasi. Katalis ZnFe2O4 dan ZnFe2O4 tersubstitusi Cu disintesis menggunakan metode kopresipitasi untuk digunakan dalam oksidasi benzil alkohol. Katalis dicirikan dengan spektrofotometer inframerah (FTIR) dan difraktometer sinar-X. Spektrum FTIR menunjukkan puncak serapan dari ikatan Zn-O dan Fe-O masing-masing pada rentang 559‒575 cm-1 dan 419‒447 cm-1. Difraktogram menunjukkan terbentuknya fase tunggal Zn0.6Cu0.4Fe2O4 pada katalis ZnFe2O4 tersubstitusi Cu 20%. Benzil alkohol dioksidasi dengan sistem refluks. Konversi benzil alkohol meningkat dengan meningkatnya suhu. Kadar benzaldehida yang dihasilkan dengan katalis ZnFe2O4 tersubstitusi Cu 20% lebih tinggi dibandingkan dengan katalis ZnFe2O4 yang tidak tersubstitusi dan yang tersubstitusi Cu 60 dan 80%. Hal tersebut menunjukkan bahwa katalis ZnFe2O4 tersubstitusi Cu 20% memiliki kinerja yang lebih baik dalam oksidasi benzil alkohol menjadi benzaldehida dengan kadar benzaldehida 8.763%.
Keyword: Benzil alkohol, katalis, oksidasi, ZnFe2O4