Objective To reveal the spatial distribution characteristics of soil nutrients in cultivated land of the Tarim River Basin, quantitatively evaluate the comprehensive soil fertility level, and provide a theoretical basis for regional precision fertilization and cultivated land quality improvement.
Methods Soil samples in the 0–20 cm plow layer were collected from the Shajingzi Reclamation Area, Tarim South Area and Tarim North Area. Soil organic matter, alkali-hydrolyzable nitrogen, available phosphorus, available potassium and pH were determined. Spatial variability of soil nutrients was analyzed by descriptive statistics, spatial distribution maps of soil nutrients were drawn by Kriging interpolation, and comprehensive soil fertility was evaluated by the Nemerow comprehensive index method.
Results Soil organic matter in the study area was generally deficient; alkali-hydrolyzable nitrogen was at a medium or higher level; available phosphorus and available potassium were at an abundant or higher level. Spatial heterogeneity of all nutrient indicators was significant, and comprehensive soil fertility was mainly limited by organic matter. The comprehensive fertility indices of the Shajingzi Reclamation Area, Tarim South Area and Tarim North Area were 1.39, 1.25 and 1.32, respectively, all graded as moderate.
Conclusion Soil nutrients in cultivated land of typical cotton-growing areas in the Tarim River Basin show significant spatial differences, and soil fertility is restricted by insufficient organic matter. In agricultural production, the input structure of nitrogen, phosphorus and potassium should be optimized, and organic fertilization and cultivated land conservation management should be strengthened.
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