Abstract: By using multi-temporal Landsat TM images and the Kappa index, this paper studied the location variation and quantification variation of the landscape elements (except for mountains and large water bodies) along the urban-rural gradient of Nanjing in 1998-2008, aimed to quantify the landscape stability and spatial differentiation during urbanization. In the study area, cultivated land presented high quantification stability but low location stability, whereas settlement had high location stability but low quantification stability. Both the location stability and the quantification stability of the waters were high, but those of forested land and other types of landscape elements were low. Along the urban-rural gradient, landscape showed increasing location stability but declining quantification stability with the increasing level of urbanization. For the urbanized area, quantification stability increased rapidly, and the composition and spatial features of landscape elements were prone to be steady. Settlement and cropland showed substantial variations in location stability and quantification stability in different zones along the urban-rural gradient, while waters and forestland were less affected in terms of the location stability and quantification stability in the zones.

Key words: supplemental irrigation by measuring soil moisture content, soil water consumption, photosynthesis, grain yield, water use efficiency, winter wheat.