RECENT LAND USE CHANGES IN CHINA 
FROM LANDSAT DATA 
by 
R. WELCH 
C.W. PANNELL 
Department of Geography 
University of Georgia 
Athens, GA 30602 
USA 
Acricultural land use in China is undergoing transformations which can 
be mapped and quantified from satellite image data.- Four regions are con- 
sidered to illustrate the possibilities of assessing agricultural development. 
In the Northeast, the formation of State farms, the introduction of 
mechanized farming practices and the reclamation of land (i.e. New Agri- 
cultural Land) have resulted in an increase in average field size from 
about 5 ha in the 1940's to greater than 20 ha in the 1870's. Shifts in 
cropping practices are apparent, with soybeans (a cash crop) declining in 
favor of food crops such as corn and wheat. 
  
In the arid far west, the Xinjiang Autonomous Region, attempts are 
underway to expand agricultural activities on marginal lands. For this 
region of China, it appears that a geographic information system (GIS) 
approach in which image data are combined with information on topography, 
soils, water, and settlement patterns can be used to evaluate the potential 
productivity of the marginal lands. An example of the GIS approach for the 
area around Urumqi will be presented. 
In the Guanzhong Plain, perhaps the oldest area of continuous Farming 
in China, very large fields up to 250 ha are associated with a crop rotation 
of winter wheat and corn or millet. Cotton is also common. Analyses of 
Landsat data reveal substantial fallow land in the Spring, which is contrary 
to the assumption that multiple cropping is a normal practice. Fallowing 
appears to be a function of several factors, including availability of 
irrigation water and proximity of the labor supply. : 
  
In the Pear] River Delta near Canton, cropping is continuous throughout 
the year, with two rice crops and a winter crop (vegetables, wheat or 
rapeseed) the normal practice. Lend quality is a major variable determining 
yields and output and may be categorized according to soil type, location, 
length of usage and distance from the sea. Based on Landsat data and 
collateral information, annual rice production figures have been estimated 
for three categories of land quality: 1) good--13.1 mt/ha; 2) adequate-- 
6.8 mt/ha; and 3) poor--2.6 mt/ha). . The distribution of these rice lands 
has been mapped and total rice production estimated for the study area. 
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