Predicting soil depth to bedrock in an anthropogenic landscape: a case study of Phewa Watershed in Panchase region of Central-Western Hills, Nepal

The Soil Depth to Bedrock (SDtB) parameter is highly variable over the landscape and is an important input for soil surface modeling including various types of mass movement that most often ignores the variability of soil depth. In landscapes that have been heavily modified by humans, SDtB parameters do not necessarily depend on natural processes, making it difficult to apply physically-based approaches. This study explored the possibility of using topographic attributes to model the SDtB in the complex topography of Phewa watershed in the Panchase region of Nepal. In June 2017, 865 SDtB points were surveyed along the excavated rural roads (approximately 300 km) within the watershed (111 km2). Topographic attributes such as slope, curvatures, altitude and compound terrain index were derived from a Digital Terrain Model along with Land use land cover attributes derived from recent Landsat remote sensing images. Utilizing these attributes as explanatory variables, we implemented simple kriging (SK) and multiple linear regressions (MLR) to predict SDtB for the watershed. The results showed that the MLR predicted SDtB map was statistically significant (R2 = 68%, EC = 0.93) over the SK (R2 = 12%, EC = -0.46). We concluded that the MLR approach in predicting SDtB for the complex geo-morphologic landscape such as the Phewa watershed in the Panchase region of Nepal can effectively be used, helping to inform the evolution of land-use as the region continues to develop.

Download Full-text

DEGRADASI LAHAN PADA KEBUN CAMPURAN DAN TEGALAN DI KABUPATEN DHARMASRAYA

Jurnal Solum ◽

10.25077/js.4.1.5-9.2007 ◽

2007 ◽

Vol 4 (1) ◽

pp. 5

Author(s):

Syafrimen Yasin ◽

Gusnidar Gusnidar ◽

Dedy Iskandar

Keyword(s):

Land Use ◽

Soil Depth ◽

Soil Surface ◽

Soil Samples ◽

Imperata Cylindrica ◽

Undisturbed Soil ◽

Fertility Status ◽

Land Use Types ◽

Bulk Volume ◽

Soil Fertility Status

A research conducted in Sungai Rumbai, Dharmasraya Regency and in Soil Laboratory Andalas university was aimed to evaluate soil fertility status on the depth below 0-20 cm from several land use types , especially under Mixed Garden and annual cultivated dryland soil. Soil samples were taken on Ultisol at 0-8% slope (late-waving soil surface). Land use types evaluated were forest, annual cultivated dryland, bush land, rangeland covered by Imperata cylindrica and mixed garden. Composite soil samples for soil chemical analysis were taken on the 0-20 cm soil depth with four replications, and 5 drillings for each replication. Undisturbed soil samples by using sample ring were used to analyze sol bulk volume. The data resulted were compared to the criteria and were statistically tested using Analysis of Variance and then were continued by LSD at 5% level. From the results of analyses could be concluded that land use for mixed garden had the higher Organic Carbon (OC) content and the lower bulk volume (BV) than those for annual cultivated dryland soil.Key Words: Degradasi Lahan, Kebun Campuran, Tegalan

Download Full-text

KLASSIFIKASI BAHAN ORGANIK TANAH BUKIT PINANG-PINANG KAWASAN HUTAN HUJAN TROPIK GUNUNG GADUT PADANG

Jurnal Solum ◽

10.25077/js.6.2.54-65.2009 ◽

2009 ◽

Vol 6 (2) ◽

pp. 54

Author(s):

Yulnafatmawita Yulnafatmawita ◽

Asmar Asmar ◽

Mimien Harianti ◽

Suci Betrianingrum

Keyword(s):

Land Use ◽

Organic Matter ◽

Soil Organic Matter ◽

Soil Depth ◽

Soil Surface ◽

Heavy Fraction ◽

The Other ◽

Annual Rainfall ◽

Mineral Particles ◽

Very High

A research about soil organic matter (SOM) classification based on the density was conducted for soil in Bukik Pinang-Pinang region. The objective of this research was to identify whether the SOM in Pinang-Pinang area, having very high annual rainfall, was mostly particulate or had been associated with mineral particles. Soils were sampled at three different land use, forest, bush, and mixed wood land on 0-10, 10-20, and 20-30 cm soil depth. Soil organic matter was classified into 2 classes, < 1.0 g cm-3 and ≥ 1.0 g cm-3 by using pure aquadest. Total and fractionated SOM samples were analyzed by using Walkley and Black method in soil laboratory, Agriclculture College, Andalas University. The result showed that, among the three land use surveyed, mixed wood land use gave the highest SOM, then followed by bush land. Soil OM content in forest ecosystem was much lower than the other two land use for the whole depth. Based on the density, SOM particulate was higher on the soil surface and decrease by depth in each land use. Among the ecosystem, SOM under forest was less associated with soil particles than that under bush and mixed wood land. Key Words: SOM-light fraction, SOM-heavy fraction, land use

Download Full-text

Proposta de Zoneamento Ambiental para a Reserva Biológica das Araucárias com Base em Atributos Topográficos

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v13.6.p3025-3041 ◽

2020 ◽

Vol 13 (6) ◽

pp. 3025

Author(s):

Ronaldo Ferreira Maganhotto ◽

Luis Claudio De PAula Souza ◽

Jairo Calderari De Oliveira Junior ◽

Marciel Lohmann

Keyword(s):

Land Use ◽

Natural Resources ◽

Digital Terrain Model ◽

Management Plan ◽

Conservation Units ◽

Terrain Model ◽

Digital Terrain ◽

Topographic Attributes ◽

Cross Tabulation ◽

Biological Reserve

O consumo dos recursos naturais trouxe à tona questionamentos sobre o que pode ser feito para evitar prejuízos cada vez maiores à natureza. Sendo assim, as Unidades de Conservação (UCs) passam a exercer papel primordial no processo de proteção ambiental. Soma-se a isso o plano de manejo, instrumento que estabelece o zoneamento da UC e as normas que devem presidir o uso da área. Nesse contexto, este trabalho objetivou propor o zoneamento ambiental da REBIO das Araucárias a partir do processamento de atributos topográficos e das suas correlações com o uso do solo. Para tanto, foram gerados diversos atributos topográficos derivados do Modelo Digital do Terreno (MDT). Como resultados, verificou-se que a utilização dos atributos topográficos possibilitou o entendimento das informações pedológicas e de limitação de uso (susceptibilidade ambiental). Logo, para o zoneamento, realizou-se tabulação cruzada entre a Limitação de Uso e o Uso do Solo, sendo delineadas as Zonas de Manejo da unidade. Environmental zoning proposal for the Araucária Biological Reserve based on topographic attributes A B S T R A C TThe consumption of natural resources has raised questions about what can be done to avoid increasing damage to nature. Thus, Conservation Units (PAs) play a major role in the process of environmental protection. Add to this the management plan, an instrument that establishes the zoning of the CU and the norms that should govern the use of the area. In this context, this work aimed to propose the environmental zoning of REBIO das Araucárias from the processing of topographic attributes and their correlations with land use. For this, several topographic attributes derived from the Digital Terrain Model (DTM) were generated. As results, it was verified that the use of the topographic attributes made possible the understanding of the pedological information and of limitation of use (environmental susceptibility). Therefore, for the zoning, a cross-tabulation was performed between the Use Limitation and the Land Use, and the Management Areas of the unit were delineated.Keywords: Geotechnology; Topographic Attributes; Protected Áreas.

Download Full-text

LYSIMETERS WITH RAINFALL AND SOIL WATER CONTROL

Hydrology Research ◽

10.2166/nh.1971.0006 ◽

1971 ◽

Vol 2 (2) ◽

pp. 79-92 ◽

Cited By ~ 17

Author(s):

K. J. KRISTENSEN ◽

H. C. ASLYNG

Keyword(s):

Soil Moisture Content ◽

Soil Depth ◽

Irrigation System ◽

Drainage System ◽

Soil Surface ◽

Trickle Irrigation ◽

Water Control ◽

Radiation Equipment ◽

Different Depths ◽

Growth Experiments

The lysimeter installation described comprises 36 concrete tanks each with a soil surface of 4 m2. The installation is useful for plant growth experiments under natural conditions involving different treatment combined with various controlled water supplies. The ground installation is at least 20 cm below the soil surface and tillage can be done with field implements. The lysimeter tanks are provided with a drainage system which can drain the soil at the bottom (100 cm depth) to a tension of up to 100 cm. A constant ground-water table at less than 100 cm soil depth can also be maintained. The soil moisture content at different depths is determined from an underground tunnel by use of gamma radiation equipment in metal tubes horizontally installed in the soil. Rainfall is prevented by a movable glass roof automatically operated and controlled by a special rain sensor. Water is applied to the soil surface with a special trickle irrigation system consisting of a set of plastic tubes for each lysimeter tank and controlled from the tunnel. Fertilizers in controlled amount can be applied with the irrigation water.

Download Full-text

Effect of period of sugarcane cultivation on the abundance and distribution of weed seeds in the soil profile

Planta Daninha ◽

10.1590/s0100-83582014000300006 ◽

2014 ◽

Vol 32 (3) ◽

pp. 507-513

Author(s):

R.O. Adereti ◽

F.O Takim ◽

Y.A. Abayomi

Keyword(s):

Land Use ◽

Soil Depth ◽

Seed Banks ◽

Soil Samples ◽

Soil Tillage ◽

Fallow Period ◽

Tillage Practices ◽

Weed Seeds ◽

Seed Distribution ◽

Screen House

An experiment was laid down in a screen house to determine the distribution of weed seeds at different soil depths and periods of cultivation of sugarcane in Ilorin, Nigeria. Soil samples from different depth levels (0-10 cm, 11-20 cm and 21-30 cm) were collected after harvesting of canes from three different land use fields (continuous sugarcane cultivation for > 20 years, continuous sugarcane cultivation for < 10 years after long fallow period and continuous sugarcane cultivation for < 5 years after long fallow period) in November, 2012. One kilogram of the sieved composite soil samples was arranged in the screen house and watered at alternate days. Germinating weed seedlings were identified, counted and then pulled out for the period of 8 months. Land use and soil depth had a highly significant (p £ 0.05) effect on the total number of weeds that emerged from the soil samples. The 010 cm of the soil depth had the highest weed seedlings that emerged. There was an equal weed seed distribution at the 11-20 cm and 21-30 cm depths of the soil. Sugarcane fields which have been continuously cultivated for a long period of time with highly disturbing soil tillage practices tend to have larger seed banks in deeper soil layers (11-20 cm and 21-30 cm) while recently opened fields had significantly larger seed banks at the 0-10 cm soil sampling depth.

Download Full-text

Correlating elements content in mosses collected in 2015 across Germany with spatially associated characteristics of sampling sites and their surroundings

Environmental Sciences Europe ◽

10.1186/s12302-019-0260-7 ◽

2019 ◽

Vol 31 (1) ◽

Author(s):

Stefan Nickel ◽

Winfried Schröder

Keyword(s):

Land Use ◽

Population Density ◽

Atmospheric Deposition ◽

Vegetation Structure ◽

Urban Areas ◽

Explanatory Power ◽

Spatial Density ◽

Area Index ◽

Explanatory Variables ◽

Tree Layer

Abstract Background The aim of the study was a statistical evaluation of the statistical relevance of potentially explanatory variables (atmospheric deposition, meteorology, geology, soil, topography, sampling, vegetation structure, land-use density, population density, potential emission sources) correlated with the content of 12 heavy metals and nitrogen in mosses collected from 400 sites across Germany in 2015. Beyond correlation analysis, regression analysis was performed using two methods: random forest regression and multiple linear regression in connection with commonality analysis. Results The strongest predictor for the content of Cd, Cu, Ni, Pb, Zn and N in mosses was the sampled species. In 2015, the atmospheric deposition showed a lower predictive power compared to earlier campaigns. The mean precipitation (2013–2015) is a significant factor influencing the content of Cd, Pb and Zn in moss samples. Altitude (Cu, Hg and Ni) and slope (Cd) are the strongest topographical predictors. With regard to 14 vegetation structure measures studied, the distance to adjacent tree stands is the strongest predictor (Cd, Cu, Hg, Zn, N), followed by the tree layer height (Cd, Hg, Pb, N), the leaf area index (Cd, N, Zn), and finally the coverage of the tree layer (Ni, Cd, Hg). For forests, the spatial density in radii 100–300 km predominates as significant predictors for Cu, Hg, Ni and N. For the urban areas, there are element-specific different radii between 25 and 300 km (Cd, Cu, Ni, Pb, N) and for agricultural areas usually radii between 50 and 300 km, in which the respective land use is correlated with the element contents. The population density in the 50 and 100 km radius is a variable with high explanatory power for all elements except Hg and N. Conclusions For Europe-wide analyses, the population density and the proportion of different land-use classes up to 300 km around the moss sampling sites are recommended.

Download Full-text

Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions

Forests ◽

10.3390/f12060666 ◽

2021 ◽

Vol 12 (6) ◽

pp. 666

Author(s):

Guilin Han ◽

Anton Eisenhauer ◽

Jie Zeng ◽

Man Liu

Keyword(s):

Soil Depth ◽

Isotope Composition ◽

Soil Surface ◽

Natural Soil ◽

Calcium Isotope ◽

Karst Forest ◽

Content Ratio ◽

The Difference ◽

Preferential Uptake ◽

Vital Factor

In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope (40Ca) is in the following order: farmland > burnt grassland > forests > grassland > shrubland. Our results further indicate that biological fractionation in a soil–plant system is a vital factor for Ca–geochemical transformations in soil surface systems.

Download Full-text

Seasonal cycles in germination and seedling emergence of summer and winter populations of catchweed bedstraw (Galium aparine) and wild mustard (Brassica kaber)

Weed Science ◽

10.1614/ws-05-107r1.1 ◽

2006 ◽

Vol 54 (1) ◽

pp. 114-120 ◽

Cited By ~ 50

Author(s):

Husrev Mennan ◽

Mathieu Ngouajio

Keyword(s):

Soil Depth ◽

Cropping Systems ◽

Seedling Emergence ◽

Seed Mass ◽

Soil Surface ◽

Burial Depth ◽

Galium Aparine ◽

Wild Mustard ◽

Seed Population ◽

Brassica Kaber

Catchweed bedstraw and wild mustard each produce two populations per year: a winter population (WP) in June, and a summer population (SP) in September. Experiments were conducted to determine whether the WP and SP differ in seed mass and seasonal germination. Seeds of both weeds were buried at 0, 5, 10, and 20 cm in cultivated fields, and retrieved at monthly intervals for 24 mo for germination tests in the laboratory. Additionally, seedling emergence from seeds buried at 0, 5, and 10 cm in the field was evaluated for 1 yr. Seeds from the WP were heavier than those from the SP for both species. Germination of exhumed seeds was affected by burial depth and by seed population. It was highest for seeds that remained on the soil surface and declined with increasing depth of burial. The WP of catchweed bedstraw produced two germination peaks per year, whereas the SP and all populations of wild mustard had only one peak. The WP of both weeds germinated earlier than the SP. Seedling emergence for both species in the field was greater for the WP than for the SP. Increasing soil depth reduced seedling emergence of both the WP and SP of wild mustard and affected only the WP of catchweed bedstraw. We conclude that the WP and SP of catchweed bedstraw and wild mustard seeds used in this study differed in seed mass, seasonal germination, and seedling emergence. The ability of a WP to produce large seeds that germinate early and have two germination peaks per year could make these populations a serious problem in cropping systems.

Download Full-text

Alpine and Subalpine Wetland Vegetation on the Bogong High Plains, South-eastern Australia

Australian Journal of Botany ◽

10.1071/bt97106 ◽

1999 ◽

Vol 47 (2) ◽

pp. 165 ◽

Cited By ~ 31

Author(s):

C.-H. Wahren ◽

R. J. Williams ◽

W. A. Papst

Keyword(s):

Soil Depth ◽

Vegetation Type ◽

Soil Surface ◽

Wetland Vegetation ◽

High Plains ◽

Composition And Structure ◽

Eastern Australia ◽

Drainage Channels ◽

Floristic Variation ◽

Steep Slopes

The botanical composition and structure of wetland vegetation from seven sites in the alpine and subalpine tracts of the Bogong High Plains was sampled in 1995 and 1996. Sites were in the vicinity of Mts Nelse, Cope and Fainter. Sampling was based on contiguous 1-m2 quadrats along transects 20−70 m long across each wetland. Samples were ordinated using non-metric multidimensional scaling (NMDS). Floristic variation was assessed both within selected individual wetlands, and between wetlands from different regions. The relationship between the ordinations and environmental variables such as soil surface texture, soil depth and the amount of bare ground was tested by fitting vectors. Three dominant vegetation assemblages were identified. Closed heath, of hygrophyllous, scleromorphic shrubs such as Richea continentis and Baeckea gunniana, the rush Empodisma minus and the moss Sphagnum cristatum occurred on the deeper peats. Low open heath of Epacris glacialis and Danthonia nivicola occurred on shallow peats. Herbfields of Caltha introloba and Oreobolus pumilio occurred on stony pavements in two different physiographic situations&horbar;on relatively steep slopes (10−20°) at the head of wetlands, and on flat ground (slope < 2°), below the head of wetlands. The pavements on the steeper sites appeared to be associated with periglacial features such as solifluction lobes and terraces. Those on the flatter ground appeared to have been derived more recently. Wetlands in the Mt Cope region consisted of closed heath, low open heath and pavement herbfield in various proportions. Wetlands on Mt Fainter, which are subject to heavy trampling by cattle, were in a degraded condition, with a low cover of major hygrophyllous mosses and shrubs, and a high cover of introduced species. Long-ungrazed wetlands in a 50-year exclosure at Rocky Valley had high cover of closed heath, no pavements, numerous ponds and virtually no entrenched drainage channels or exposed peat. The Caltha herbfields are significant features nationally, both floristically and geomorphologically. Alpine and subalpine wetlands have been listed under the Victorian Flora and Fauna Guarantee Act 1988, and continued grazing by cattle is not compatible with the conservation objectives for this alpine vegetation type.

Download Full-text

Reconnaissance Mapping for Land-use Planning in the Natal Drakensberg, South Africa

Environmental Conservation ◽

10.1017/s0376892900025315 ◽

1977 ◽

Vol 4 (2) ◽

pp. 103-108 ◽

Cited By ~ 2

Author(s):

Gerald G. Garland ◽

J. Pelham Chisholm ◽

Colin R. Christian

Keyword(s):

Land Use ◽

Land Use Planning ◽

Land Use Changes ◽

Mass Movement ◽

Land Use Pattern ◽

Erosion Rates ◽

Reconnaissance Survey ◽

Adequate Understanding ◽

Geomorphological Processes ◽

Detailed Work

Changes in land-use can have an important effect on rates of erosion and denudation. In order to avoid accelerating erosion rates, decision makers in land-use planning require adequate information on the contemporary geomorphological processes and hydrology of areas where modifications in the land-use pattern are envisaged. The first phase in the acquisition of the information is the reconnaissance survey, which shows where and how the erosional status of an area is likely to be affected, and also acts as a foundation on which to base more detailed work in the future.The Solitude area is an active erosional system, dominated by mass movement and fluvial processes. The rate of removal of material is likely to be increased by modifications in land-use which, from other points of view, would be considered entirely suitable for the area. Therefore, if accelerated denudation is to be avoided, projects involving land-use changes should be implemented only by those having an adequate understanding of the mechanism of geomorphological processes operating in the area.

Download Full-text