Abstract:

【Objective】 The spatial variability of the soil cation exchange capacity (CEC) was studied in order to provide a theoretical basis for the improvement of saline soil fertility management in saline soil improvement of cultivated land of Yucheng City. 【Method】 With the GIS technical support, using Sequential Gaussian Simulation to achieve variance (SGSV),Sequential Gaussian simulation of the average achieved (SGSA) and the Ordinary Kriging interpolation (OK) to study the spatial variability of soil CEC in cultivated land of Yucheng City. And the statistic characteristics, spatial structure of semi-variances and spatial distribution trend were compared between the unobserved value, SGSV, SGSA and OK. 【Result】 SGSV had the same data configuration as the measured values and the simulated value was uncertain for the unobserved points. The estimated value by OK and SGSA changed the original data configuration with obviously smoothing-average effect, and SGSA is better than OK method in eliminating smoothing-average effects. The soil CEC of high levels are mainly distributed in the north and east side of Yucheng City, and the low levels are mainly in the north, north-west and south areas. 【Conclusion】 The results of SGSA were of great significance for reduction of salinity content and rational fertilization of the saline-alkali soil in Yucheng city.

Key words: GIS, soil cation exchange capacity (CEC), semi-variances, Kriging, Sequential Gaussian Simulation