The Ecological Perspective of Landslides at Soils with High Clay Content in the Middle Bogowonto Watershed, Central Java, Indonesia

Abstract

e clay layers at hilly regions in the study area were very thick. e presence of very thick clay caused several difficulties in terms of environmental management, particularly in reducing georisk due to landslide. However, initial observations proved that areas of active landslides had better vegetation cover. e objective of this study was to find out ecological roles of landslides in livelihood in the Middle Bogowonto Watershed. e ecological roles of landslide were examined through field empirical evidences. Texture, bulk density, permeability, structure, and index plasticity were conducted for analyses of soil physical properties.Stepwise interpretation was made using 1 : 100,000-1 : 25,000 Indonesian topographic maps and remote sensing images of 30 m-<10 m spatial resolution. e results showed that landslides formed three landform zones: residual, erosional, and depositional zones. e area that did not slid, the residual zone, had massive soil structure and very hard consistency. Crops cultivated in this zone did not grow well. In the areas of active landslide, the environmental conditions seemed to be more favorable for living creatures. e landslides resulted in depositional zones with gentle slopes (4°to 15°), higher water availability, and easier soil management. e landslides also acted as the rearrangement process of landforms for better living environment.

Environmental damage assessment due to traditional mining on local scale in the Wungkal Hills, Yogyakarta-Indonesia

“…Calculating the safety factors in southwest Saudi Arabia, Basahel and Mitri (2019) affirm that rock structure, slope gradient, and slope aspect significantly determine the slope condition. Also, Zapico et al (2018) The interaction between steep slopes and high rainfall intensities triggers the occurrence of landslides and erosions (Sartohadi et al, 2018). Excavation walls or cliffs that exceed the criteria create a risk of working accidents and endanger the surrounding settlements.…”

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

“…The landslides gravitationally redistribute soil mass and change the position of soil layers, which generally have different characteristics and have different potential uses [1][2][3][4][5]. The results of soil redistribution by landslides can be observed in three slope zones from the highest elevation to the lowest elevation, namely residual, erosion, and deposition [6][7][8].…”

“…Very thick soils combined with the high elevation, and the steep slope angles make the volcanic foot slope prone to landslides. On the contrary, the volcanic foot slope has a great potential for agricultural sector development, especially in the former landslide area, where the soils have favorable characteristics to support plant growth [8]. One of the problems that might limit the agricultural sector development at the volcanic foot slope zone is a limitation on irrigation water availability, thus rain-fed agriculture is widely applied in the area.…”

“…Land 2020, 9, x FOR PEER REVIEW 2 of 20 growth [8]. One of the problems that might limit the agricultural sector development at the volcanic foot slope zone is a limitation on irrigation water availability, thus rain-fed agriculture is widely applied in the area.…”

Relationship between soil morphology and variability of upland degradation in Bogowonto Watershed, Central Java, Indonesia

“…The middle side is the transition zone of Sumbing Quaternary Volcanic System and Menoreh Tertiary Volcanic-Structural System. Most of the middle side constituent material is based on weathered volcanic material and additional volcanic ash material, and is, therefore, extremely vulnerable to geomorphic processes (Sartohadi et al, 2018). Generally, land degradation in the agricultural sector causes a decrease in the soil quality and quantity in producing biomass, thereby disrupting the stability of the ecosystem, which impacts the harmony of human life.…”