Volcanic Foot Research Articles

Maize stover transfers from maize fields to banana-based agroforestry homegardens and the corresponding nutrient flows in central-northern Tanzania

Maize (Zea mays) stover produced in the drier lowland areas on the volcanic foot slopes of Mount Kilimanjaro serves as an important additional fodder for smallholder zero-grazed dairy cattle farming in the humid highland areas of the region. The obtained cattle manure is used to replenish nutrients and manage soil fertility in banana-based agroforestry homegardens of the highlands, which contributes significantly to sustaining crop production, thus food security and the livelihoods of the community. The study aims to provide a preliminary evaluation of the amounts of stover removed from smallholder maize-based fields in the lowlands and the subsequent nutrient flows to the banana-based agroforestry homegardens of the highlands. In 54 smallholder maize fields selected at random from 11 villages in the Hai and Siha districts of the Kilimanjaro region, we conducted an agronomic survey to record the types and amounts of fertilizer used, plant spacing at harvest, and maize stover biomass yield. Most of the surveyed maize-based fields received inadequate nutrient inputs, which were limited to mineral nitrogen alone if any. Of the surveyed fields, 16.7% received recommended amounts of 74 kg N ha–1 by the Ministry of Agriculture, 46.3% sub-optimal amounts and 37.0% did not receive fertilizer at all. Plant density was only 50% of the recommended population density. While this was only a preliminary study on nutrient flows between maize and banana-based agroecosystems, our findings demonstrated that potassium exports via harvested banana bunches exceeded the inputs in the homegardens. We conclude that (i) soil fertility management techniques, preferably integrated soil fertility management, suitable for small-scale maize production in the lowlands should be formulated while optimizing plant density to increase production, (ii) maize-based agroforestry farming system adapted to drier conditions to deal with windstorm and soil erosion problems in the lowlands is urgently needed, and (iii) wider and more detailed research on nutrient flows between maize and banana-based agroecosystems should be conducted to document their respective soil nutrient balances and the sustainability of such practice.

Pendekatan Hidrogeomorfologi Dan Pendugaan Geolistrik Untuk Identifikasi Potensi Airtanah Di Jedong Malang

This study aims to identify the potential groundwater in Jedong, Malang, East Java. The hydrogeomorphological approach is a suitable approach to describe the relationship between hydrological and geomorphological processes on and below the earth's surface. The survey of geoelectricity complements the hydrogeomorphological approach. It will give a better description of the groundwater conditions below the earth's surface. Based on the research, there are 2 hydrogeomorphological units in the study area, which are: Volcanic Foot Valley Unit and Volcanic Foot Ridge Unit. The best groundwater potential is in Volcanic Foot Valley Hydrogeomorphological unit, namely Awar-awar Valley and Cokro Valley. The valleys are dominated by gully erosion and landslides. They have surface deposits up to a depth of 7 meters, and lots of outcrops of breccia, pumice, and andesite boulders. The valley’s springs discharge between 56 - 198 m3/day. The average infiltration rate in the valley is 1776 mm / hour, with sandy soil material. The best aquifer consisting of sandy material is more than 10 meters in depth, based on the geoelectrical survey. Water in the aquiclude layer, cannot be exploited because it is breccia and tuff material. The Sawah valley cannot be exploited further because the groundwater potential is very low. This can be identified by the thick water outflow seepage. In the Volcanic Foot Ridge Hydrogeomorphological unit, the groundwater potential is also very small. Hydrogeomorphically, water will flow down the slope to the valley. It will reduce the infiltration rate. In general, the ridge area is only used for settlement, while the slopes are used for dryland agriculture. The geoelectric analysis results show that the groundwater potential is at a depth of more than 45 meters. This research’s results show that the combination of the hydrogeomorphological approach and the geoelectric use will provide a better description of the potential groundwater.

THE CHARACTERISTICS OF INFILTRATION ON THE SOUTHERN FLANK OF MERAPI VOLCANIC PLAIN, YOGYAKARTA, INDONESIA

The broad development of built areas has decreased infiltration areas, which in turn gives impacts on water table subsidence. The infiltration capacity and distribution are factors that need to consider in preserving the groundwater. This research aims to examine the infiltration rate, infiltration capacity, and distribution of potential infiltration on the southern flank of the volcanic foot plain and the fluvial-volcanic plain of Merapi Volcano. The method employed in this research is a direct measurement using a double-ring infiltro-meter. The constant infiltration rate was analyzed using the Horton Method. The results show that the high infiltration rate spreads over an area with an altitude of less than 200 Meter Above Mean Sea Level (MAMSL) which has very deep groundwater. Meanwhile, the infiltration rates above 200 MAMSL tend to be smaller in shallower groundwater depths. The infiltration capacity in the research area tends to be high. The highest infiltration rate is 1.2 cm/minute with the infiltration equation of ft = 1.20 + (1.967-1.20)e - 0.0492t, while the lowest infiltration rate is 0.1 cm/minute with the infiltration equation of ft = 0.10 + (0.149-0.10)e -0.0396t. Most of the research areas have moderate or fairly rapid infiltration capacity that spreads from areas below 200 MAMSL to the top altitude at 400 MAMSL. The potential for water infiltration in the research area mostly belongs to the medium category. Overall, this paper presents new insights to understand the characteristics of infiltration in volcanic plain related to the development of land use.

Trees and Crops Arrangement in the Agroforestry System Based on Slope Units to Control Landslide Reactivation on Volcanic Foot Slopes in Java, Indonesia

Agroforestry, as the dominant land use at the volcanic foot slope in Java Island, is prone to landslide due to a combination of rough relief and thick soil layer. However, evaluations of specific vegetation patterns against landslide reactivation due to soil erosion, which relays on the existing slope units and geomorphological processes, are still limited. The research data were collected through aerial photo interpretation by delineating morphological units of old landslides, slope units, and the existing land use. This was followed by field surveys for two consecutive purposes, i.e., (1) verification of aerial photo interpretation and (2) identification and intensity assessment of existing geomorphological processes. The data were tabulated according to slope units, as a basis for tree and crop arrangement in controlling erosion and landslide, by considering economic, social, and ecological functions. The agroforestry would control the landslides reactivation if the tree and crop arrangement was based on the morphological units formed by the previous landslide. The slope units are classified into residual zones at the highest elevations with flat slopes, erosion zones with the steepest slope, and sedimentation zones at the lowest elevations with gentle slopes. Trees and crops at those three units of the former landslide have different functions in controlling processes of rill erosion, gully erosion, and soil creep.

The Potential of Umbul Sungsang Spring Water for Drinking Wate, PDAM, and Irigation Purposes at Banyudono, Boyolali, Central Java

Umbul Sungsang spring located in the foot of a Merapi is on shift zone between volcanic foot plain and fluvial volcanic fott plain constitutes spring belt. Up to the present, the population use that spring for drinking water and irrigation. The planning of taking water by Municipal Waterworks to supply Solo population causes people around it worried because the usually use that spring. Therefore it is needed to conduct a research to know the potential of that spring. The aim of this research is to account how much the need of drinking water, manucipal waterworks and irrigation and the potential of the spring which is available. The research uses survey method. Primary and secondary data are collected, analyzed quantitatively by using software aid to do simulation the need of irrigation. The result of the research shows that the need of drinking water is 0.068 lt/second/day taken in dry season; manucipal waterworks uses 200 lt/second/day and for irrigation is about 442.2 lt/second/day with the pattern rice – tobacco – rice. Irrigation is also supplied from Bendung Bukur Ireng. The result of the research also shows that in October period I, II, III, and November period II and I lack of water. Therefore municipal waterworks must not use water on Otober and November, while on July and September adjust to the rest of discharge of water, which is available. Its water quality fulfils the requirement for various needs.

Kajian Hidrogeomorfologi Mataair di Sebagian Lereng Barat Gunungapi Lawu

Magma activities on earth surface cause dynamic of volcanic morphology from the volcanic cone up to fluvial volcanic plain. The changing of morphology is always followed by different slope, composition and thickness of material, and break of slope. This geomorphological conditions result in groundwater emerges forming spring belt. Accordingly, wether such phenomena are also the case in the west slope of Lawu volcano is investigated in this reseach. Hydrogeomorphology approach is applied to study of the spring characteristic and distribution in the research area. The result research shows that the distribution pattern of springs in the west slope of Lawu volcano is not like spring belt perfectly, like the strato volcano generally. It is caused by erosion processes, mass wasting intensively, Lawu fault and other faults. Most springs flow on the volcanic slope and volcanic foot morphology.

Hydromorphology of the Unconfined Groundwater in the South of Klaten District (Data Before Earthquake Mei 27th 2006)

There are some characteristics and distributions of unconfined groundwater variation in the research area. Those are related to a system of water supply and consumptive use for drinking water. Variation of the groundwater characteristic depends on variation of morphology. Therefore, it is needed to delineate hydromorphology units of the regions as a base on groundwater resources management, especially for drinking water. The aims of the research are: (1) to study of the characteristic and distribution of unconfined groundwater variations base on landform units, (2) to study the factors that affect such variations, and (3) to establish the hydromorphology units of the regions for groundwater resources management, especially for drinking water. The method used in this research is landform approach and field survey. The sampling method is stratified sampling, based on landform as the analysis approach. Result of the research shows that there are some variations of groundwater characteristic at each landform. Landforms which have good groundwater characteristic are Hydromorphology Unit of Fluvio Volcanic Plain of Young Merapi (except Bayat region) and Hydromorphology Unit of Volcanic Foot Plain of Young Merapi. At those units, there are good quality of groundwater, bicarbonate water (hydrochemical type I), having low electric conductivity, shallow of water table, low in fluctuation, and middle to fast class in aquifer permeability. Those units are the most potential unconfined groundwater resources management for drinking water. The units which have poor groundwater characteristic are Hidromorphology Unit in Bayat Region, including Undulating Alluvial Plain, Fluvio Volcanic Plain of Young Merapi, and Swamp Alluvial Plain. Generally, the groundwater quality is medium to poor, the hydrochemical type is Va (initiation process of connate water) and type III (evaporate water), shallow up to medium of water table, and low to middle class of aquifer permeability. The taste of groundwater is brackish to saline with high concentration of chloride.

Geomorphological Approach for Regional Zoning In The Merapi Volcanic Area

Geomorphologial approach can be used as the basic for identifying and analyzing the natural resources potentials, especially in volcanic landscape. Based on its geomorphology, Merapi volcanic landscape can be divided into 5 morphological units, i.e.: volcanic cone, volcanic slope, volcanic foot, volcanic foot plain, and fluvio-volcanic plain. Each of these morphological units has specific characteristic and natural resources potential. Based on the condition of geomorphology, the regional zoning can be compiled to support the land use planning and to maintain the conservation of environmental function in the Merapi Volcanic area.

Groundwater Characteristic and Fresh Water Supplying System of the East Slope Merapi Volcano

slope of Merapi Volcano in Boyolali. The aims of this study are first to know the characteristic of groundwater in every morphological unit, second to know supplying system of fresh water in every each unit.The method used is survey method. The sampling use to know the characteristic groundwater both quality and quantity of the water, and supplying system of fresh by using area sampling. As basic of stratification of its region is morphological unit. Analysis method used is tabulation, laboratory analysis, and graphic analysis to describe its space.The result of the study shows that the quality of groundwater in every morphological unit is good enough, but in general the contents of element Ca, Mg, N03, CI, SO4, HCO3 shows that the lower the region is, the higher the content of the element . But if it is seen from the depth of its groundwater, so that the fluvial volcanic plain is the shallowest, then the fluvial volcanic foot plain and the last the volcanic foot area. Supplying system of fresh water, which derived from the dominant of well water, is especially used in morphological unit in fluvial "volcanic foot plain. The spring water is used by the population in the morphological unit in volcanic foot plain and then in morphological unit of fluvial volcanic foot plain. The population uses much rainwater in the morphological unit of volcanic foot plain.

Geographical Distribution of Dairy Cattle in Boyolali

The researcch about the geographic distribution of diary cattle breeders, is held in Subdistrict of Selo, Cepogo, Musuk, Boyolali, Mojosongo, Teras, and Banyudono, Boyolali regency. This research aims to investigate potential areas for dairy attle breeding and the physical factors (availability of groundwater, average temperature, altitude, accesibility) that contribute most to the density of cattle in the research site. In addition, it investigates the differences m water supply for dairy cattle breeding and the ratio of income to cost at every morphological units as well as the effect of the amount of water supply on milk production and the effect of the Ca content of groundwater on the density of dairy cattle. The methods use in the research is survey method. The data colleted in the research consist of 200 primary data of the respondents taken from head of dairy cattle breeders families using a questionnare. Secondary data are obtained from related agencies, reference books and other authorized source dealing with the research yopic. In order to find out the differences in water supply for dairy cattle breeding and the ratio of income to cost, a statistical measurenment with Anova test is carried out. A multiple regression test is used to find out the effects of the availability of groundwater, altitude, average temperature, and accesibility on the density of dairy cattle. A simple regression test is used to find out the effects of water supply on milk producctin and the Ca sontent of groundwater on the density of dairy cattle.The result of the research indicate that the research site consist of four morphological units, namely the Volcanic slope, Volcanic foot, fluvio Volcanic foot, fluvio volcanic plain. The potential areas for dairy cattle breeding are situated at an altitude of 700 meters, temperature 17o C – 21o C especially the areas in the subdistrict of Selo and Cepogo. The result of the statistical test indicate that the most differences in the amount of water supply for dairy attle breeding as well as in the rasio between income and cost among morphological units. Water supply for dairy cattle breeding has no effect on milk production, whereas the Ca content of groundwater has no effect on the density of dairy cattle.

Land Capability in Gobeh Sub Watershed Wonogiry Regency Central Java Province

The research held on Sub DAS of Gobeh, Wonogiri Regency, have the aims to kno about class and sub-class of land capability in the research area. The other aim is to know about some area developed to the farming land, and to evaluate about land apability currently. The method used in this research is field-survey method, including about observation, measurenment, reording, and laboratory analysis. The sampling method applied in this research is stratified sampling, with land unit stratum. Measurenment and recording in the field inluding about degree of slope, erosion level, soil-deepening, drainage, stone or gravel and flood hazard. The laboratory analysis including about land erodibility, texture, and permeability. The research result identify that, researh fields have three lanf form unit, they are the fluvio volanic foot plain of old Lawu vulcan area flat relief slightly dissected, the fluvio volcanic foot plain of old Lawu mountain area rolling relief medium dissected, and flat foot plain unit can be separated to thirty two land unit. Land capability of the research field identify between level II to level VII. The wide of each land capability are, level II 3 – 8 Ha (2,4%), level III 38,18 Ha (23,7%), level IV 10 Ha (6,33%), level V 107,62 Ha (66,8%), level VII 1,2 Ha (0,75%).

The Potential of Umbul Sungsang Spring Water for Drinking Wate, PDAM, and Irigation Purposes at Banyudono, Boyolali, Central Java

Umbul Sungsang spring located in the foot of a Merapi is on shift zone between volcanic foot plain and fluvial volcanic fott plain constitutes spring belt. Up to the present, the population use that spring for drinking water and irrigation. The planning of taking water by Municipal Waterworks to supply Solo population causes people around it worried because the usually use that spring. Therefore it is needed to conduct a research to know the potential of that spring. The aim of this research is to account how much the need of drinking water, manucipal waterworks and irrigation and the potential of the spring which is available. The research uses survey method. Primary and secondary data are collected, analyzed quantitatively by using software aid to do simulation the need of irrigation. The result of the research shows that the need of drinking water is 0.068 lt/second/day taken in dry season; manucipal waterworks uses 200 lt/second/day and for irrigation is about 442.2 lt/second/day with the pattern rice – tobacco – rice. Irrigation is also supplied from Bendung Bukur Ireng. The result of the research also shows that in October period I, II, III, and November period II and I lack of water. Therefore municipal waterworks must not use water on Otober and November, while on July and September adjust to the rest of discharge of water, which is available. Its water quality fulfils the requirement for various needs.

DEFORMATION OF IWAKI VOLCANO, NORTHERNMOST HONSHU, JAPAN

The final purpose of this study is to clarify the relation between the deformation of Iwaki volcano and that of its adjacent areas from a viewpoint of “tectono-volcanology”. In this paper, however, the author discussed mainly on the deformation of the volcano itself. The geomorphological and volcanological significances of the deformation of Iwaki volcano and the relation to the deformation of adjacent areas will be discussed in the following paper which will be appeared in this Review. Iwaki volcano (1625m) rests on the tilting hills which are mainly made up of the gently inclined monoclinic sedimentary rocks older than upper Pliocene (Figs. 1, 2 and 3). This volcano is a composite volcano composed of a main strato-volcano, three parasitic lava domes, and some craterlets (Figs. 4 and 5). Some tens of eruptions of rather small scale took place on the flank of the main cone in historic times. The latest one was solf atara activity in 1970. It is noteworthy for geomorphology of the Iwaki volcano that conspicuous asymmetry between the western half of the volcanic cone and the eastern is found in some features such as the gradient of restored original slope of the main cone, the distribution of “planezes” or volcanic initial surfaces of the main cone, the development of alluvial fans at the volcanic foot, and so on (Figs. 4, 6 and 11). There are, however, no evidences showing that the above-mentioned asymmetry depends on the geologic structures of the volcano (Fig. 6). Lateral volcanoes and craterlets are also distributed asymmetrically (Fig. 5). At the foot of the volcano except the western foot are found some deformed geomorphic surfaces. They are the Rdaino surface which is a part of older volcanic initial surface in the earlier stage of Young Iwaki volcano, the Nenoyama surface which is a part of volcanic initial surface of the main cone, the Hiramitai surface which is a part of Oldermost alluvial fan at the volcanic foot, and the Oldermost, Old and Middle alluvial fans at the volcanic foot, in descending order of their formations (Figs. 12, 13, 15, 16 and 17). Among these geomorphic surfaces, the older three were reversely inclined toward the main cone from which the materials forming these surfaces were derived, and also the younger three were decreased in their gradients in similar trend to that of the older ones. The present main cone is surrounded except at the western foot by the circular hills, named Old Iwaki volcanic hills, which are higher than the foot of the main cone (Fig. 18) and are composed of lavas and pyroclastics of Old Iwaki volcano (Fig. 6). Old Iwaki volcano is presumed to be a strato-volcano and now to be buried in the inside of the present main cone of Young Iwaki volcano. The inner border line of the Old Iwaki volcanic hills is circular in shape and is about 5.5 to 6.5 km in radius from the topographic center of the present main cone. At the southern foot of the present main cone, the innermost part of Old Iwaki volcanic hills is deformed by normal faults dipping toward the center of the volcano (Figs. 12 and 19). These faults run in the direction which is not parallel to the general trend of fault system in adjacent areas of the volcano (Fig. 2), but concentric to the center of present main cone. Deformation processes of Iwaki volcano inferred from the facts mentioned above are as follows: The central part (about 5km in radius) of Old Iwaki volcano subsided forming the circular faults before the beginning of the activities of Young Iwaki volcano. The main cone of Young Iwaki volcano had been also subsiding or down-warping slowly so as to incline eastward during the period from the formation of most parts of volcanic initial surfaces of the main cone to at least just before the formation of Young alluvial fan at the volcanic foot.