Effect of α-Pinene on the Soil Bacterial and Fungal Population and Soil Organic Carbon in Eucalyptus Plantations
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Date
2019-02
Authors
Dahanayake, P.M.
Premetilake, M.M.S.N.
Henegamage, A.P.
Herath, H.M.S.K.
Journal Title
Journal ISSN
Volume Title
Publisher
Uva Wellassa University of Sri Lanka
Abstract
Nutrient cycling is essential for the stability of an ecosystem where soil microorganisms play a significant role. Some allelochemicals such as α-pinene produced by certain plant species may suppress the activity of these microorganisms. Eucalyptus, which is a popular plantation species in Sri Lanka, is known to emit α-pinene. However, its effect on soil microorganisms and soil fertility is not well known. The present study investigated the relationship between α-pinene content, soil microorganisms and soil organic carbon content in 7-year-old Eucalyptus grandis and Eucalyptus torelliana plantations. As the control plantation, an adjacent Patna grassland (previous land-use before afforestation) was used. Three subplots (20 × 20 m) were established within each site and soil was sampled up to 15 cm depth. Soil organic carbon content was measured according to the Walkley-Black method. Following a serial dilution, bacteria and fungi were cultured and CFU mL-1 was calculated. The α-pinene in soil samples was extracted using petroleum ether and was analyzed using GC-MS. According to the results, there was a significant (P<0.05) variation between organic carbon, α-pinene content and bacteria quantity between the plantations and the adjacent grasslands. However, there was no significant (P>0.05) variation in fungi quantity. The highest organic carbon content was observed in E. torelliana plantation (2.08% ±0.3), however; the highest α-pinene content was found under E. grandis plantation (0.14% ± 0.09). Interestingly, the highest bacterial count was recorded under E. grandis plantation (3.0 x 105 CFU mL-1) while the highest fungi count was recorded in grassland. There were no significant (P>0.05) correlations between the soil α-pinene content, soil bacterial and fungal count fungal and the organic carbon. There is no significant effect (P>0.05) of α-pinene content on the bacterial and fungal counts and organic carbon in young E. grandis and E. torelliana plantations.
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Keywords
Bioprocess Technology, Biotechnology, Bio Chemicals Engineering