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【Objective】 This paper aimed to clarify the chronological change in nutrients and fertility of soils grown with tobacco in Honghe prefecture. 【Method】 Total of 296 and 881 tobacco-growing topsoil samples were collected in 2014 and 2018, respectively. Soil fertility indexes and nutrients variation characteristics were evaluated and analyzed based on fuzzy mathematical theory, t-test and multiple comparison.【Result】 Compared with 2014, the average value of soil organic matter, alkali-hydrolyzable nitrogen and available potassium increased by 2.81 g/kg, 9.61 mg/kg and 16.74 mg/kg, respectively, and soil available boron and exchangeable magnesium decreased by 0.22 mg/kg and 51.69 mg/kg in 2018, respectively. Judging from the variation characteristics of nutrient groups, the group with slightly alkaline (7.5-8.5), the group with very high content (>40 g/kg) of organic matter, the group with moderate content of soil alkaline hydrolyzable nitrogen (100-150 mg/kg), the group with very high content (>350 mg/kg) of available potassium and the group with very low content (<0.3 mg/kg) of soil available boron were significantly higher in 2018 than in 2014, increased by 47.83%, 80.59%, 12.21%, and 72.19%, and 38.84%, respectively. In 2018, the group with very low (<10 g/kg) of organic matter, the group with low (65-100 mg/kg) of soil alkaline hydrolyzable nitrogen, the group with very low (<10 mg/kg) of soil available phosphorus, the group with medium (0.50-1.0 mg/kg) of soil available boron and the group with very high content (>400 mg/kg) of exchangeable magnesium group decreased by 46.0%, 17.02%, 16.57%, 41.36% and 30.87% compared with 2014, respectively. The group with high and very high content of effective zinc reached 80.14% and 85.37% in 2014 and 2018, respectively; And the group with moderate and above exchangeable magnesium content was ranged from 76.05% to 83.54%. The soil organic matter and alkaline hydrolyzable nitrogen contributed the most to the soil fertility of tobacco-growing soil in 2014 and 2018, respectively. In 2018, the average value of soil fertility index for tobacco-growing soil was 0.49, and the coefficient of variation was 26.53%. The soil with lower, medium and higher soil fertility index accounted for 20.66%, 61.29% and 17.03%, respectively. Compared with 2014, the percentage of lower and higher soil fertility index increased by 3.43% and 0.13%, respectively, and the percentage of medium soil fertility index decreased by 1.88%. There was no difference between low and medium soil fertility in each county ( city) in 2014 and 2018, only the higher soil fertility grade in Mile city showed significantly higher in 2018 than that in 2014. 【Conclusion】 The overall fertility of tobacco-growing soil in Honghe prefecture was good and the variation was small. Soil organic matter and alkaline-hydrolyzable nitrogen content were the main factors affecting the soil fertility of tobacco-growing soil in Honghe prefecture. The soil showed high content of available zinc and exchangeable magnesium, abundant organic matter, alkali-hydrolyzable nitrogen, and available potassium, but lack of available boron content. It is recommended to increase the use of boron fertilizer and reasonably control the application of zinc and magnesium fertilizers. [ABSTRACT FROM AUTHOR]

[Objective] The aim of this paper is to fully understand the temporal and spatial variation of soil nutrient in the cultivated land in Kunming district. [Method] Based on the analysis of 3907 farmland soil samples collected from 7 counties in Dianehi district of Kunming city, combined with ‘3S’ technology, the spatial distribution and change of soil nutrient content of farmland in Kunming city were studied. [Result] The results showed that the area with medium available boron content in the cultivated land in Dianehi district of Kunming city accounted for 70.08%, and the area with deficient available boron content accounted for 28.29%. The area with medium available zinc content accounted for 63.18% . Most areas of other nutrients were rich or more abundant. According to the average value of soil nutrient, the total nitrogen and alkali hvdrolysable nitrogen in the Dianehi district of Kunming city reached a rich level, while the organic matter, available phosphorus and available potassium were rich. Except for available boron, the average contents of effective manganese, effective zinc and effective molybdenum of trace elements were in high or higher level. The nutrient contents of vegetable land and seasonal vegetable land were higher than that of the dry land of fruit trees. [Conclusion]The total nutrient content of arable soil in Dianehi district of Kunming city is rich. Compared with the second national soil survey data, the contents of soil organic matter, total nitrogen, alkali hvdrolysable nitrogen, a-vailable phosphorus and available potassium are generally increasing. In the process of fertilization, it is necessary to combine the technology of improving the soil quality of cultivated land to achieve precise fertilization, and improve the utilization rale of fertilizer and the ability of soil fertilizer supply. [ABSTRACT FROM AUTHOR]