Abstract: 【Objective】By studying the spatial-temporal variation characteristics of tobacco-planting soil nutrients in Erhai Lake Basin (ELB), the objective of grading evaluation and spatial visualization of tobacco-planting soil fertility in this region was achieved, so as to provide scientific basis for the nutrient management, balanced fertilization, and the control of agricultural non-point source pollution of tobacco-planting areas in ELB.【Method】Based on the 964 tobacco-planting soil samples in ELB collected in 2011-2013, 2018 and 2020, this study explored the spatial-temporal variability of nutrients and regional distribution patterns using Geostatistics, Geographic Information Systems (GIS) technology, and Fuzzy integrated fertility index method to quantify the soil fertility in tobacco-planting areas. 【Result】The average values of soil pH, soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP) and available potassium (AK) of tobacco-planting soil in the ELB were 7.34, 59.55 g kg^-1, 3.49 g kg^-1, 54.43 mg kg^-1, and 191.99 mg kg^-1, all of which belonging to moderate variation. Tobacco-planting soil was rich in SOM, TN, available AP and AK, and the proportions of areas within the upper-middle level accounted for 85.2%, 93.8%, 94.2% and 78.8% , respectively, showing obvious variation at regional scale. The area of tobacco-planting soil fertility were graded to five levels (from high to low: I to V), which accounted for 8.0%, 21.60%, 38.11%, 28.9% and 3.49%, respectively. 【Conclusion】The pH of tobacco-planting soil was relatively alkaline in ELB, which was higher in the northern than in the southern; the highest concentrations of SOM and TN occurred in the northern and the western region; the areas with high AP concentration were distributed in patches in the upper and middle region of the Sanjiang River, Eastern eastern and western region; the areas with high AK concentration were distributed in flakes in the northern and eastern of Erhai Lake. Collectively, the fertility of the tobacco-growing soil in ELB was in high level, and the high-quality soil areas above Grade III were mainly distributed in the northern and eastern region.

Key words: tobacco field, soil nutrient, spatial-temporal variability, assessment of soil fertility, Erhai Lake Basin