Soil acidification under long-term tobacco plantation results in alterations of mineralogical properties in an Alisol |
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| Authors: | Yuting Zhang Xinhua He Jian Zhao Yueqiang Zhang |
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| Institution: | 1. College of Resources and Environment, Southwest University, Chongqing, China;2. National Monitoring Station of Soil Fertility and Fertilizer Efficiency on Purple Soils, Chongqing, China;3. Centre of Excellence for Soil Biology, College of Resources and Environment, Southwest University, Chongqing, China;4. Technology Research Center, Zunyi Tobacco Company, Zunyi, China |
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| Abstract: | In the present study, soil samples collected from 20-year (1993?2013) long-term tobacco plantation and perennial fallow were analyzed to study the influence of soil acidification on soil physicochemical and mineralogical properties. Results showed a significant decrease of soil pH, Ca2+, Mg2+, Na+ and total exchangeable cations, except K+, under tobacco plantation than under fallow land. Further X-ray diffraction (XRD) analysis for 1 mm soil size demonstrated an increase of vermiculite and kaolinite, but an obvious decrease of original potassium-bearing mica and potassium feldspar, under tobacco plantation than under fallow. For the <2 μm soil clay fraction, the XRD patterns showed an obvious desilication and accumulation of Al and Fe under tobacco plantation than under fallow. Other potassium-bearing minerals, such as illite and chlorite, had also visibly weathered and slaked under tobacco plantation than under fallow, resulting in an increase of vermiculite and hydroxy-Al-vermiculite, and an accelerated decomposition of 2:1 minerals and formation of 1:1 minerals. These results demonstrated that long-term continuous tobacco plantation has exerted negative effects on soil acidification and maintenance of soil potassium-bearing minerals. |
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| Keywords: | Alisol cation Nicotiana tabacum potassium-bearing minerals X-ray diffraction (XRD) |
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