PROPERTIES AND MANAGEMENT IMPLICATIONS OF SOILS FORMED FROM VOLCANIC MATERIALS IN LEMBANG AREA, WEST JAVA

Soils formed from volcanic materials have a high potential for agricultural development, especially for horticultural crops, tea, and pine trees. Data on the characteristics of these soils are important for the management planning. Six representative soil profiles developed on andesitic volcanic ash and tuff in Lembang area, West Java were studied to determine the soil physical, chemical, and mineralogical properties, to study the relationship between the soil properties, and to classify the soils according to the Soil Taxonomy. The results indicated that all the soils had very deep (>150 cm) solum. In general, the volcanic ash soils were darker colored, more granular, more friable, less sticky and less plastic than the volcanic tuff soils. Physically, the ash soils had lower bulk density (0.44-0.73 mg m-3) and higher available water content (13-33%) than the tuff soils. Bulk density decreased with increasing allophane. Chemically, the ash soils had higher pHNaF (mostly > 10), higher organic carbon (4.3-6.8% in upper horizons), higher CEC (20- 44 cmolc kg-1), and higher P retention (> 85%) than the tuff soils. P retention logarithmically increased with increasing oxalate extractable Al and allophane. The sand fractions of the ash soils were dominated by hornblende, while the tuff soils were predominantly composed of opaque minerals. In the clay fractions, the ash soils were dominated by allophane, whereas the tuff soils showed high contents of gibbsite and metahalloysite. Soils developed on volcanic ash were classified as Thaptic Hapludands and Typic Melanudands, while soils formed from volcanic tuff were classified as Andic Dystrudepts. The low bulk density and friable consistency of the soils contributed to favorable soil tilth. However, high P retention and Al saturation in most soils are limiting factors for plant growth. Application of P fertilizers and liming coupled with efficient placement can be recommended to enhance P availability and reduce Al toxicity. Organic matter can be used to reduce Al toxicity. Soil conservation needs to be considered, especially in the steep slope areas

Characteristics of Spodosols, Limitation and Usage Potential

Spodosols characterized by the presence of spodic and albic horizons, are problem soils due to low productivity, coarse texture and low nutrient status. This soil was generally covered by alang-alang or shrub and bush. The soils were generally distributed in cold climate or wet tropical areas with high rainfall. The objectives of this paper were to discuss the characteristics ofSpodosols in Kalimantan and Sumatra and the possibility of their utilization. In Indonesia, this soil is found in Kalimantan, Sulawesi, Sumatra, and Papua Islands. Parent materials of the soils were originated from quartz sand, sediment or acid sedimentary rocks (quartz sandstone) with low nutrients status. Physiographically, the soils were distributed in alluvial plain, colluvial, sand beach, sand dune, tectonic plain and sandstone plateau on elevation of 5 to >1,500 m asl, with flat to nearly undulating relieves. The soil physical properties were characterized by coarse texture and the presence of root limiting layer such as fragipan, duripan, or placic horizon (organo-metal complex) with various depth. The soil chemical properties were characterized by acid soil reaction, very low exchangeable bases, P and K nutrient, and mineral reserve. Cation exchange capacity of the soils depends on their soil organic matter content. Based on the soil characteristics, most Spodosols were not suitable for agricultural land development. Therefore the Spodosols usages should be directed not only for production increases but also for environmental healthiness and soilcare. The Spodosols land that have been opened needs to be optimally used in order to increase soil quality through appropriate soil and plant management. The new land cleared for agriculture and production forest needs carefully actions with localizing the Spodosols distribution in order to maintain the natural vegetations as conservation forest or recreation areas

Properties of Soils Developed from Ultramafic Rocks and their Land Suitability for Cocoa in East Kolaka Regency, Indonesia

Soils developed from ultramafic rocks are widely distributed in East Kolaka Regency, Southeast Sulawesi Province, Indonesia. However, the soil characteristics and their land suitability for cocoa crop have not been known. Three soil profiles developed from ultramafic rocks in East Kolaka were described, sampled, and analyzed to characterize their mineralogical, physical, and chemical properties. Results indicated that sand mineral composition was dominated by opaque, quartz, and garnet minerals, while clay minerals were composed of kaolinite, goetite and hematite. All the soils were characterized by clay textures, low bulk density (0.89-1.04 g/cm3), medium to very high available water (11-22%), and rapid permeability (13-25 cm/hour). The soil reaction was acid (pH 4.64-5.03). The soil organic carbon was medium in A horizon (2.02-2.95%) and very low in B horizons (0.35-0.87%). The N total values were medium to high in A horizon (0.37-0.51%) and low to very low in B horizons (0.07-0.18%). The available P and potential K2O contents were very low, while the potential P2O5 content was low to medium (18-35 mg/100g).The exchangeable Ca content was low to very low (0.23-2.94 cmolc/kg), while the exchangeable Mg content was low to high (0.22-2.59 cmolc/kg). The soil CEC was low to very low (3-12 cmolc/kg), while clay CEC was very low (< 6 cmolc/kg). The base saturation was low to medium (19-51%), while Al saturation was very low (<3%). At family level, all the soils were classified as fine, kaolinitic, isohyperthermic, Rhodic Hapludox, All soils were marginally suitable (S3 class) for cocoa crop with limiting factors of acid soil reaction and very low potential K2O. Liming and NPK fertilization should be applied to increase the soil productivity for cocoa development. Keywords : soil properties, ultramafic rocks, land suitability, cocoa, East Kolak

Characteristics of Volcanic Ash Soils From Southern Part of Mt. Tangkuban Perahu, West Java

Three soil pedons developed on young andesitic volcanic ash with high mineral deposit and high P retention, granular soil structure, high porosity, and low bulk density, were differentiated based on their morphological, physical, chemical and mineralogical characteristics. Pedons 1 and 3 are discontinue or bisequm pedons characterized by the presence of more contrast colour and new buried materials on layer 4, while pedon 2 isrelatively younger than pedons 1 and 3. Mineralogical composition of pedons 1 and 3 is very different compared with pedon 2. Pedons 1 and 3 have high total porosity resulting in easy to the soil leaching. Pedon 2 with higher bulk density tends to be more compact although its soil texture is light, indicating soil character of Andisols from this young volcanic material. High P retention and low base saturation may bring about high Pfertilizer need. Pedons 1 and 3 have lower feldspar content as K sources compared with pedon 2, while the content of opaque minerals is higher in pedons 1 and 3 indicating more developed pedons. The top layer of pedon 1 has lower opaque minerals but higher hornblende than pedon 3 due to different land use. The presence of alophane minerals in pedon 1 and 3 can be detected from the results of Selective Dissolution Analysis, but they do not detected on X-ray diffraction patterns. In pedon 2, however, alophane minerals show convex diffraction patterns. Based oncharacteristics of their soil physics, chemistry, and mineralogy, pedons 1 and 3 were classified as Thaptic Hapludands, and pedon 2 as Typic Melanudands. The increase of P availability on the three pedons can be done by P fertilization and liming to accelerate substitution of Al-P to Ca-P and increase of soil pH

Andisols Derived From Acid Pyroclastic Liparite Tuff : Their Properties and Their Management Strategy for Agricultural Development

The characterizations of Andisols from acid pyroclastic liparite tuff have been studied. Six soil profiles were made in the field, and 29 soil samples were taken for chemical, mineralogical and physical analyses in laboratory. Results indicate that sand mineral composition of Andisols was dominated by biotite, quartz, and sanidine, while the clay mineral was dominated by allophane. Soil bulk density is low (0.47-1.00 g cm-3), while total porosity is high (53-80%). Soil reaction is slightly acid (pH 5.5-6.0) to very acid (pH< 4.5), poor of nutrients, have a high to very high of P retention (>80%), high (>3%) to very high organic carbon (>5%) and high potential K (>41 mg 100g-1). The high value of organic carbon positively has relationship with N and soil cation exchange capacity, while the P retentionpositively has relationship with amorphous material in the form of Alo+0.5 Feo. Andisols investigated were classified as Medial, amorphic, isothermic, Acrudoxic Hapludands (UG 444 and MD 121 ), Medial, amorphic, shallow, isothermic, Duric Hapludands (KR 227), and Medial, amorphic, shallow, isothermic, Acrudoxic Hapludands (KR 190, AI 1045 and KR 1188). The characterization of Andisols is very useful in the soil management planning on Andisols land. Planting some vegetation that tolerant with soil acidity and soil conservation to protect organic matter from erosion hazard should be become priority. Maintain land cover of Andisols is a good way to protect Andisols from erosion process

Properties, Genesis and Classification of Soils on Volcanic Materials in Lembang Area, West Java, Indonesia

Soils developed on volcanic materials have high potential for agricultural production. However, the productivity of some of them is below their potential capacity. Proper management of these soils must be based on understanding their nature and properties. Lembang is one of the most intensively cultivated areas for horticultural crops, tea and pine trees in West Java, Indonesia. Unfortunately, data on the characteristics of soils developed on different volcanic materials of different ages in this area are still limited. Thus, six representative soil profiles developed on andesitic volcanic ash and tuff were studied. The objectives of this study were to determine the soil physical, chemical, mineralogical and micromorphological properties, to relate the soil properties to soil-forming processes and to classify the soils according to Soil Taxonomy and World Reference Base. The results of this study show that all the soils have very deep solum (>1 50 em). Some soil profiles developed on volcanic ash have buried organic-rich horizons as a result of repeated thin ash deposition. In general, the volcanic ash soils are darker coloured, more granular, more friable, less sticky and less plastic than the volcanic tuff soils. The ash soils generally have silt loam to clay loam textures, while the tuff soils have clay texture. The ash soils have lower bulk density (0.38 to 0.79 Mglm\ higher total porosity (55 to 84%) and higher available water content ( 1 3.0 to 34.6%) than the tuff soils. The pH H20 of the soils ranges from 3.52 to 5 .88. Some soil profiles in both parent materials show high exchangeable Al (2.2 to 5.9 cmolc/kg). The ash soils have higher pHNaF (> 9.4), higher organic carbon (up to 1 0%), and higher phosphate retention (> 85%) than the tuff soils. The high values of pHNaF and phosphate retention in the volcanic ash soils are related to the presence of large amounts of amorphous AI. The CEC is generally higher in the ash soils (22 to 46 cmolc/kg) than in the tuff soils ( 1 8 to 3 1 cmolclkg). The base saturation is generally low « 1 5%) in the upper horizons of all the soils. The sand fractions of the ash soils are dominated by hornblende, while the tuff soils are predominantly composed of opaque minerals or magnetite .. In the silt fractions, all the soils in both parent materials show traces to minor amounts of cristobalite, tridymite and quartz. Gibbsite is only observed in the loamy tuff profile, while hydrated halloysite is only present in the lower horizons of another tuff profile. In the clay fractions, the ash soils are dominated by allophane with varying amounts of cristobalite, whereas the tuff soils show a high content of gibbsite and metahalloysite

Mineralogical, Physical, and Chemical Properties of Soils From Andesitic Volcanic Tuff of Mt. Burangrang, West Java

Information of soils on andesitic volcanic tuff in Indonesia is still limited. Three soil pedons, formed in andesitic volcanic tuff situated in the intensively cultivated vegetable growing areas and secondary forest areas around the Mt. Burangrang, were studied to understand the physical, chemical and mineralogical properties of these soils. All pedons are located in the middle slope with elevation of about 1000 m above sea level (asl). Bulk and undisturbed soil samples of each horizon were analyzed in the laboratory. The results indicated that all the pedons have very deep solum (> 150 cm), granular to subangular blocky structuresand friable to very friable consistences. Mineralogy of the clay fraction of pedons 2 and 3 is dominated by metahalloysite, whereas large amounts of gibbsite are only present in pedon 1. Mineralogical composition of the sand fraction is predominantly composed of opaque minerals, while weatherable minerals such as hornblende, augite, hypersthene and plagioclase (andesine and labradorite) are present in various amounts. Soil bulk density values are generally less than 0.9 mg m-3. Soil reaction is acid to extremely acid, whereas soil pH NaF is of less than 9.4. Aluminum saturation is high in pedon 3 and upper horizons of pedon 1. Organic carbon contents are generally medium in the surface horizons and decrease with depth. Exchangeable bases are dominated by Ca and Mg in medium to very low amounts, cation exchange capacity is medium to high, and base saturation varies ranging from very low to medium. All the pedons studied do not meet the requirements of andic soil properties (P retention of less than 85%), and are classified as Andic Dystrudepts. Thelow bulk density may contribute to the more favourable soil tilth leading to easy tillage and root development. However, high soil acidity in most soils studied is a limiting factor for plant growth

Soils Developed on Serpentinite in Panyipatan District, South Kalimantan : Characteristics and Their Suitability for Maize

Four representative soil pedons formed from ultrabasic or serpentinite parent materials were studied in the field and laboratory in order to determine their soil characteristics and suitability for maize. Maize is one of the most important agricultural food crops in Indonesia. Up to now, the need of this crop for any other USAges tends to increase. However, maizeproduction could not meet the demand. Therefore, extensification and intensification of the agricultural area for the crop cultivation need to be conducted. The results indicated that all the studied soils have deep solum, yellowish red to red colour, blocky structure, and friable to firm consistency. Particle-size distribution was dominated by clay fraction (73-88%). The soil bulk density and available water was relatively low (0.84-1.12 mg m-3 and 9-15%, respectively), while the total porosity was high (58-68%). Except pedon PN-35, some soils have acid reaction, medium C organic in the upper horizons, and low base saturation (<40%). The soil CEC and exchangeable Al were low (<12 and <1.3 cmolc kg-1, respectively). P retention of all the soils is high (60-87%). The soils were classified as Typic Hapludox, Anionic Acrudox, and Kandiudalfic Eutrudox. Most soils were moderately suitable (S2) for maize cultivation with nutrient retention (acidreaction, low CEC-clay and base saturation) and water availability (high wet months) as the main limiting factors. To increase soil productivity, application of agricultural lime, P fertilizers (rock phosphate) and organic matter were highly recommmended