An understanding of soil fertility and its change in oasis cropland plays crucial role in sustainable development of agriculture in arid areas. Geographical information system and geo-statistics were employed to reveal spatial and temporal variability of soil fertility quality in topsoil (0～20 cm) in Linze oasis cropland in northwestern of China during 1982—2008. Soil fertility quality indices in 287 soil samples in the study area included soil organic matter (SOM), total N, available N, available P, and available K. Results showed that concentrations of SOM, total N, available N, available P, and available K were 13.8 g·kg^-1, 0.81 g·kg^-1, 64.4 mg·kg^-1, 32.3 mg·kg^-1, 199 mg·kg^-1, respectively, and they increased from 1982 to 2008 by 13.5%, 7.8％, 9.3%, 225.6％, and 26.8％, respectively. The variation coefficients of soil fertility indicators were more than 25%. Fuzzy mathematics comprehensive evaluation method is a valuable tool for evaluation of soil fertility quality in the study area. The integrated soil fertility quality developed from an intensive spatial variability in 1982 into a moderate spatial variability. The soil fertility quality in 2008 in the study area were 4, 5, 6 and 7 grades based on national agricultural soil fertility grading standards, and there were increasing trends for soil fertility compared with in 1982. Distribution map of integrated soil fertility quality in the study provides new insights in the reasonable utilization of soil resources.

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