The application of remote sensing technology in evaluating, mapping the laterization area in Lang Son province


Posted at: 09:07:58 05/07/2016 - Read: 189
Từ khóa Key words: laterite, laterization, gis

Nowaday, environmental issues become top concerns of all humanity. In many countries in the world including Viet Nam, the environment are being degraded, natural resources become depleted. Laterization is one of the forms of land degradation; it’s affects the life of organisms which live inside and above the soil surface.

Literization is the process of leaching, accumulating the cations Fe 3+, Fe 2+, Al 3+, Mn6 +, in the soil, under the impact of environmental conditions such as weathering, runoff, groundwater level change, loss vegetation, erosion.

Determining the area and the level of soil laterization is one of the basis for assessing land degradation. Nowaday, the method of using GIS technology to mapping the laterization landis one of the advanced methods, it has great benefit in evaluating and determining the laterite area. The Geoinformatics research center, Thai Nguyen University of Agriculture and Forestry have used this method to serve the projects " Investigating land degradation in Lang Son province " according to the following diagram:

The diagram of mapping laterization

Firstly, we needs to identify the laterite area from the documents of another projects. The project has updated information related to the literization, rocks and stones from the related documents, then we compare the laterite areas that was drowed on the map with the new data that collected from fieldwork.

From the fieldwork data, and the result of comparison, we drow new laterite data and decentralize laterite levels as following table:

The table of decentralizing laterite levels

No

Laterite levels

Symbol

Value

1

No laterite

KvN

Not appear laterite

2

Low level laterite

Kv1

The amount of laterization area <5%, smooth size and less than 6mm, appear in the soil layer that ≤ 70cm depth.

3

Medium level laterite

Kv2

The amount of laterization area from 5-15%, medium size, appear in the soil layer from 30 -70cm depth.

4

High level laterite

Kv3

The amount of laterization area ≥ 15%, large size ≥20 mm, appear in the soil layer from 0-30cm depth or all the soil profile

Based on the available soil maps and results of the fieldwork, we import the laterization data into the land parcel. Using symbology tool in ArcGIS to editting and mapping the laterite map in Lang Son province. Finally, we obtained the following results:

The laterization map of Lang Son province
Posted by: GIRC

GeoInformatics Center - Thai Nguyen University of Agriculture and Forestry

Address: Quyet Thang commune, Thai Nguyen city, Vietnam | Tel: +84904.031.103

Email: girc.tuaf@gmail.com | Website: www.girc.tuaf.edu.vn