Erosion in hill soils of bangladesh (original) (raw)
Related papers
Estimation of soil erosion on cultivated fields on the hilly Meghalaya Plateau, North-East India
Geochronometria, 2011
The estimation of soil erosion rates in complex subtropical agricultural systems of hilly environment is difficult and most of the traditional methods have serious limitations. The 137 Cs technique allows to obtain relatively quickly retrospective medium term soil erosion results. The objective of this study was using 137 Cs approach to quantify soil loss under agricultural system which develops under growing human pressure on the hilly terrain of the Meghalaya Plateau. The measured values of caesium inventory for all sampling points are between 2% and 63% of the reference value of caesium inventory. The estimated annual soil loss for sampling points located on the slope are between 29 and 79 Mg·ha -1 ·yr -1 in the case of an improved mass balance model. It means that soil erosion in this manually tilled agricultural area cannot be neglected.
A Study on Soil Erosion in Pasighat Town (Arunachal Pradesh) India
Natural Hazards, 2004
Pasighat which lies on the foothills of the Himalayas is one of the important towns of Arunachal Pradesh. A very turbulent river named Siang flows through the town and causes frequent flash floods, inundating the low-lying areas. This river and town is also under threat due to continuous soil erosion. This soil erosion affects the neighbouring state of Assam as well. Due to the soil erosion this river known as Brahmaputra in Assam is constantly changing its course making a large number of water channels with sand bars thus inundating vast cultivable land every year. The study analyses the cause of the problem at Pasighat in the backdrop of the existing river system, morphology and the geographical evolution of the Trans Himalayas.
An Appraisal of Soil Erosion in Dehradun Valley
Journal of Scientific Research
In the recent past, there has been a very rapid increase in the developmental activities in the Himalayas in general and Dehradun Valley in particular. These comprise large-scale construction, roads, mining activity, overgrazing, and deforestation etc. leading to the land degradation. A near exponential population growth has placed a further heavy demand on already limited natural resources. High rainfall coupled with fragile rocks and good relief provides a dense network of stream system. The debris from landslides and mine waste cause inequilibrium in flow regime causing meandering in both mountain and valley streams. These problems pose serious threat to environmental and ecological balance in an already fragile eco-system. Landslide, river sedimentation, disruption to communication lines and depletion of water sources are some of the direct consequences of mass erosion problem. The effect of majority of casualties and other natural hazards due to mass erosion often disrupts econ...
International Journal of Plant & Soil Science
The present study uncovering the impact of erosion conservation techniques on soil attributes in Shivaliks of lower Himalayas of Jammu. Soil erosion is considered as the main cause of land degradation in hilly areas espially in outer Himalayas. Although the problem persisted on the earth for a longer period, it has become severe in recent times due to increased man-environment interactions. The study was conducted in 2021 at the Merth village of Jammu and Kashmir, India, which is situated in the Kathua district. The catchment area investigated had a clay loam texture and a slope gradient of 3-6%, with a total area of 24.8 acres. The result shows that mean value of bulk density under various erosion control techniques was highest in overgrazing prevention (1.40g cm-3) followed by perimeter runoff control, terrace farming and contour plowing and was lowest in cover crop (1.33g cm-3). The carbon content also increased with the and was highest under cover crop. Carbon act as bridge betw...
Soil erosion associated with an upland farming system under population pressure in Northeast India
Land Degradation & Development, 2012
Rapid increase in population and growing demand for agricultural products has generated changes in land use and upland farming systems and resulted in erosion and land degradation over large tracts of northeast India. The spatial variation of soil erosion rates was studied, in a small catchment under a modified form of shifting cultivation on the hilly Meghalaya Plateau, using the 137 Cs technique. Soil erosion and deposition patterns are much influenced by land use. The estimated annual soil loss from cultivated fields ranged from 32 to 79 Mg ha À1 y À1 and reached only 0Á5 Mg ha À1 y À1 from degraded grassland. Calculated soil erosion rates from cultivated fields exceed that which can be produced by weathering of new soil from parent materials. Observed intensification of agricultural production will lead to progressive conversion of cultivated fields into degraded grasslands and other changes to land use in the upper part of the Meghalaya Plateau.
Thesis: TRIBHUVAN UNIVERSITY CENTRAL DEPARTMENT OF GEOLOGY NEPAL, 2005
ABSTRACT The present dissertation work covers the monitoring and observation of erosion processes in the study area. The work correlates these activities with the local geology. The degradation and loss of soil is a serious problem affecting the production of the world’s food crops. The present study area lies in the Siwalik rocks, which are chiefly represented by, channel lag, vertical accretion and lateral accretion deposit. Such very loose, fragile and less consolidated rocks are some factors of Soil Erosion in the Siwalik. Moreover, the thrusts, steep topography and intense rainfall within a limited time period are the most prominent triggering factors for the Soil Erosion. The soil erosion includes the erosion of sediment and the nutrient element of the soil. The erosion from gullies, hill slopes and bank cutting were considered for the determination of the soil erosion. From active Gullies, Erosion plots and Bank scouring the rate of erosion was observed with iron peg method (Moeyersons and Tervuren 1990). In possible cases, a visible portion of painted red iron rod is exposed and was monitored on regular basis. The gullies were also monitored from their head, side bank, width and longitudinal slopes. The flood level was measured with the measuring rod at possible condition. At the time of high flood and impossible cases (night and unhealthy condition), record of the peak flows were measured from the line drawn on the monitoring stations painted in the wall of embankment. The sediment concentrations were determined through the filtration of floodwater. The velocities of the flow were measured from the floatation method. The total erosion or gross erosion within the catchment is the sum of all types of erosion as inter rill, rill, gully, channel, and other mass wasting. The relative importance of different type of erosion varies from one area to another. The soil erosion from the Khajuri Catchment indicate from origination and development of gully, surface erosion and bank cutting respectively places the first, second and third position. The net erosion from the Khajuri catchment is estimated 34,700 m³ per year which is equivalent to 92, 000 ton km¯². Using rational formula for estimating the peak flows and empirical formula given by Rziha in the same site, the estimation of the sediment yield is 6,000 ton km¯² (Ghimire et al. 2003). This study was estimated the suspended sediment from the catchment at the same location, without considering the riverbed load. The gross estimation of sediment production in this study gives the sediment delivery ratio is 15 per year. The different techniques are available in computing the soil loss. The model applied RUSLE, Musgrave, A. Zingg model gives the soil loss rate 2380, 2307, 3153 tons per year. It is nature’s law that upland area is prone to degradation. The issue is how to protect the environment and conserve the available resources. The activity of denudation and deposition should favour the environment of upper and lower reach.
Causes and consequences of soil erosion in northeastern Himalaya, India
Current Science
The Northeastern Region of India, due to its geographical location in the eastern Himalaya, exhibits unique features of hilly terrain and abundant rainfall with wide spatial variability. Due to inappropriate and unsustainable land-use practices along the steep hill slopes, the region is prone to severe water erosion and soil loss. Only a few discrete, small-scale studies on measured soil loss in the region are available. Inadequate information at the regional level restricts devising site-specific soil and water conservation measures for the vulnerable areas of this region. To illustrate regional scenarios for future use, including projection studies, we have reviewed studies of soil loss in the region over the past three decades. The literature revealed significant variation in annual soil loss measured or estimated (range) across different land-use practices: traces to 229.5 t ha-1 yr-1 in shifting cultivation (jhum) and traces to 836.0 t ha-1 yr-1 in other non-jhum major land uses (agriculture, open forest and wasteland). The information generated will help prioritize research activities and in planning conservation measures for various stakeholders.
International Journal of Environment, 2020
The coastal soils of Bangladesh are preferentially dominated by silt content and stressed by salinity (Na+) as well as low humus content . Hence, these soils are moderately to extremely vulnerable to water erosion, which is a major form of land degradation. The aim of this study was to estimate the soil erosion rate from maize fields in the southwestern coastal region. A field experiment was conducted on maize grown field, which is nearly level, moderately saline, and silt dominated coastal land. The plots were amended with inorganic fertilizer, sieved sand, and decomposed cow dung. Each runoff plot was connected to separate reservoirs and was exposed to rainfall. From the erosive rainstorms, representative critical rainfall intensity was determined. The entrapped eroded material in the reservoirs was collected to estimate the loss of soil. The efficacy of the applied amendments was studied in terms of lowering seasonal (maize growth period) soil loss and erosion associated deter...
Stochastic Environmental Research and Risk Assessment
Soil erosion due to anthropogenic interventions is an emerging threat to the southeastern coastal districts of Bangladesh. In the recent decade, land degradation intensi ed this process in this region due to the settlement of the Forcibly Displaced Myanmar Nationals (FDMNs) popularly known as 'Rohingya', who ed from Myanmar in 2017. The present study has attempted to quantify the regional soil loss (from 2015 to 2020) using the Revised Universal Soil Loss Equation (RUSLE) model. Results showed that the year 2015 and 2020 witnessed the mean soil erosion at a rate of around 58.2 and 59 t ha-1 yr-1, respectively in the Cox's Bazar district in which 20-21% of the study area was highly subjected to soil erosion. But in the Rohingya camps mean soil erosion for these periods is 59 and 78 t ha-1 yr-1, respectively with a cumulative increase of 32%. The sub-districts adjacent to the Rohingya refugee camps (Ramu, Ukhia, and Teknaf) have experienced intense erosion compared to the others. From 2015 to 2020, a large increase of about 4.54 (6%) t ha-1 yr-1 is observed in the Palongkhali union whereas a maximum decrease of about-8.08 (23%) t ha-1 yr-1 is observed in the Pokkhali union. In Rohingya camps, the worst soil erosion-affected areas are the camps 8E, 10, 14, 15, 16, and 17 having more than 100 t ha-1 yr-1 mean soil loss. Landuse change is the major contributing factor for soil erosion increase from 2015 to 2020 identi ed from the geographic detector method. The spatial variations are signi cantly controlled by slope and elevation factors. This work can help to understand the dynamics of soil erosion and the knowledge can be used for conservation planning in the Cox's Bazar and Rohingya camp areas.