Assessment for Salinized Wasteland Expansion and Land Use Change Using GIS and Remote Sensing in the West Part of Northeast China

Abstract

Due to human impact under climatic variations, western part of Northeast China has suffered substantial land degradation during past decades. This paper presents an integrated study of expansion process of salinized wasteland in Da'an County, a typical salt-affected area in Northeast China, by using Geographic Information Systems (GIS) and remote sensing. The study explores the temporal and spatial characteristics of salinized wasteland expansion from 1954 to 2004, and land use/cover changes during this period. During the past 50 years, the salinized wasteland in study area have increased by 135,995 ha, and in 2004 covers 32.31% of the total area, in the meantime grassland has decreased by 104,697 ha and in 2004 covers only 13.15% of the study area. Grasslands, croplands and swamplands were found the three main land use types converted into salinized wasteland. Land use/cover changes shows that between 1954 and 2004, 48.6% of grasslands, 42.5% of swamplands, and 14.1% of croplands were transformed into salinized wasteland, respectively. Lastly, the major factors influencing salinized wasteland expansion and land use/cover changes were also explored. In general, climatic factors supplied a potential environment for soil salinization. Human-related factors, such as policy, population, overgrazing, and intensified and unreasonable utilization of land and water resources are the main causes of salinized wasteland expansion.

The causes of soil alkalinization in the Songnen Plain of Northeast China

“…In 2000, there was only about 1.8 9 10 6 ha grassland and 1.0 9 10 6 ha wetland, decreased by 71.9 and 86.8%, respectively; while the salinized area was up to 3.2 9 10 6 ha (Wang et al 2004a, b, c;Zhao et al 2004;Wang et al 2005;), increased about 18.5%. Li et al (2007) studied that increased salinized area mainly originated from grassland and wetland.…”

Variations on Soil Salinity and Sodicity and Its Driving Factors Analysis under Microtopography in Different Hydrological Conditions

“…Songnen Plain, northeast China, is one of three major saline-sodic soil distribution regions in the world. The area of saline-sodic soil is about 2.57ˆ10 6 ha, approximately 22.62% of its total area [4,5]. The area of saline-sodic soil is increasing at an annual rate of 1.35ˆ10 4 ha.…”

“…The area of saline-sodic soil is increasing at an annual rate of 1.35ˆ10 4 ha. In some counties, the salinization land accounts for more than 20% of the total area and has been changed into wasteland [6]. Soil salinization has caused serious soil degradation, which negatively influences the economic development and decreased the yield of local crops.…”

Impacts of Climate Change and Anthropogenic Activities on the Ecological Restoration of Wetlands in the Arid Regions of China

“…Blindly exploiting agricultural land and occupying natural wetlands for the purposes of building urban constructions in the reserve zone directly resulted in the abatement of natural wetland areas of the HRB and their reduced ability to support ecological functions. Since the building of large reservoirs and canals in the late 1970s to the late 1990s in the Sanjiang Plain will altered the hydrological process of the study region and led to wetland degradation [48,49]. There are two sides to human interference in wetland; however, the key is to ensure a balance.…”