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191.
Highland catchments in tropical regions are frequently subjected to soil erosion and the transport of chemicals downstream.
Any drastic changes in land use will increase the severity of these processes of land degradation. A simulation study using
GLEAMS (Groundwater Loading Effects of Agricultural Management Systems) was conducted at a catchment presently under tea farming
in Cameron Highlands, Malaysia. Soil, water and nutrient transport associated with several alternative land uses was studied.
In addition, the effect of a disruptive form of land clearing on soil, water and nutrient losses was also investigated. Modelling
with GLEAMS required information from field measurements and observations, laboratory analyses, guide tables, industry records,
maps and reports published by soil survey and meteorological departments.
The most critical step in simulating soil and water movement using GLEAMS is the identification of a representative flow sequence.
In the catchment under study, the representative flow sequence was overland flow–channel 1–channel 2. Input data on soil erodibility,
porosity and surface roughness were manipulated to represent various degrees and forms of disturbance to the surface soil
layer. For all land uses studied, the highest soil loss was predicted for the overland flow area where slope gradient is high
and the soil friable. The variations in soil loss, runoff and nutrient loss between landscape elements and between land uses
were consistent with soil erosion features observed in the field. Soil and nutrient losses were substantial for crops such
as cabbage that required land shaping activities and frequent ploughing of the soil. Predicted data on enrichment ratio of
specific surface (ERSS) are consistent with nutrient enrichment processes in the field and could prove to be useful in studies
on chemical transport in highland catchments. 相似文献
192.
Biomonitoring of multi-element atmospheric deposition using terrestrial moss is a well-established technique in Europe. Although
the technique is widely known, there were very limited records of using this technique to study atmospheric air pollution
in Malaysia. In this present study, the deposition of 11 trace metals surrounding the main petroleum refinery plant in Kerteh
Terengganu (eastern part of peninsular Malaysia) has been evaluated using two local moss species, namely Hypnum plumaeforme and Taxithelium instratum as bioindicators. The study was also done by means of observing whether these metals are attributed to work related to oil
exploration in this area. The moss samples have been collected at 30 sampling stations in the vicinity of the petrochemical
industrial area covering up to 15 km to the south, north, and west in radius. The contents of heavy metal in moss samples
were analyzed by energy dispersive x-ray fluorescence technique. Distribution of heavy metal content in all mosses is portrayed
using Surfer software. Areas of the highest level of contaminations are highlighted. The results obtained using the principal
components analysis revealed that the elements can be grouped into three different components that indirectly reflected three
different sources namely anthropogenic factor, vegetation factor, and natural sources (soil dust or substrate) factor. Heavy
metals deposited mostly in the distance after 9 km onward to the western part (the average direction of wind blow). V, Cr,
Cu, and Hg are believed to have originated from local petrochemical-based industries operated around petroleum industrial
area. 相似文献
193.
Abdullah E. Akay Fatih Sivrikaya Sercan Gulci 《Environmental monitoring and assessment》2014,186(5):2741-2747
Riparian forests adjacent to surface water are important transitional zones which maintain and enrich biodiversity and ensure the sustainability in a forest ecosystem. Also, riparian forests maintain water quality, reduce sediment delivery, enhance habitat areas for aquatic life and wildlife, and provide ecological corridors between the upland and the downstream. However, the riparian ecosystems have been degraded mainly due to human development, forest operations, and agricultural activities. In order to evaluate the impacts of these factors on riparian forests, it is necessary to estimate trends in forest cover changes. This study aims to analyze riparian forest cover changes along the Firniz River located in Mediterranean city of Kahramanmaras in Turkey. Changes in riparian forest cover from 1989 to 2010 have been determined by implementing supervised classification method on a series of Landsat TM imagery of the study area. The results indicated that the classification process applied on 1989 and 2010 images provided overall accuracy of 80.08 and 75 %, respectively. It was found that the most common land use class within the riparian zone was productive forest, followed by degraded forest, agricultural areas, and other land use classes. The results also indicated that the areas of degraded forest and forest openings increased, while productive forest and agricultural areas decreased between the years of 1989 and 2010. The amount of agricultural areas decreased due to the reduction in the population of rural people. According to these results, it can be concluded that special forest management and operation techniques should be implemented to restore the forest ecosystem in riparian areas. 相似文献