Abstract:
Objective The aims were to comprehensively evaluate the soil nutrients’ levels of the cultivated land in Lanzhou city, to find out their distribution characteristics and influence factors, and then to propose reasonable fertilization suggestions.
Method In this study, 618 cultivated soil samples were collected from five counties of Lanzhou, and the soil organic matter, total nitrogen, rapidly available potassium, available phosphorus contents and pH value were determined. Principal component analysis was used to evaluate soil nutrients comprehensively, and the influence factors of soil nutrient comprehensive level were analyzed by geographically weighted regression model (GWR).
Result ①The cultivated soil in the research area was alkaline, the contents of soil organic matter and total nitrogen were generally low, the rapidly available potassium contents were rich, and the available phosphorus contents were uneven. ②The soil comprehensive nutrients in the research area were mainly of low-level, accounting for 50.46% of the total cultivated area in the research area, medium and extremely low grades were next, accounting for 29.61% and 19.30% of the total cultivated area, and the higher level land rarely accounted for only 0.63%. Soil organic matter and total nitrogen contents were the main limiting factors for the comprehensive level of soil nutrients in cultivated land. ③The comprehensive level of soil nutrients of cultivated land in the study area was relatively low and greatly affected by altitude and annual average temperature.
Conclusion In the research area, the cultivated land soil nutrients distribution is uneven, and the comprehensive level of nutrients is low. The comprehensive nutrient level is mainly affected by altitude and the average annual temperature factors. It is suggested to balance fertilization according to the soil comprehensive nutrient levels, nutrient abundance and crop growth requirements.
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