Soil health impacts of rubber farming: The implication of conversion of degraded natural forests into monoculture plantations

High revenues from rubber latex exports have led to a rapid expansion of commercial rubber cultivation and, as a consequence, the conversion of different land use types (e.g., natural forests) into rubber plantations, which may lead to a decrease in soil health. In this study in Quang Tri Province, Vietnam, we determined: (1) the variation of soil health parameters along a chronosequence of rubber tree stands and natural forests and (2) the relationships and potential feedback between vegetation types, vegetation structures and soil health. Our results revealed that: (1) soil health was higher in natural forests than in rubber plantations with a higher values in higher biomass forests; (2) soil health was lower in younger rubber plantations; (3) soil health depends on vegetation structure (with significantly positive relationships found between soil health and canopy cover, litter biomass, dry litter cover and ground vegetation cover). This study highlights the need for more rigorous land management practices and land use conversion policies in order to ensure the long-term conservation of soil health in rubber plantations

Compositional analysis of the leaf, stem and rhizome oils of Piper lolot C. DC. from Vietnam

The essential oils isolated by hydrodistillation from the fresh leaves, stems and rhizomes of Piper lolot C. DC. have been analyzed for the first time by a combination of GC and GC/MS. The oils contained more than 35 compounds, of which 25 constituents could be identified according to their chromatographic retention indices and mass spectra. The main constituent of the oils was beta-caryophyllene (26.1-30.9%). The rhizome oil contained bornyl acetate (10.0%) as second major component

Chemical composition of the essential oil of Artemisia vulgaris L. var. indica Maxim. from Vietnam

The essential oil of the leaves of A. vulgaris var. indica of Vietnamese origin was analyzed by a combination of GC and GC/MS. Forty-six components were identified, of which the major ones were b-caryophyllene (24.1%) and b-cubebene (12.0%

Composition of the essential oil from the aerial parts of Piper pierrei C.DC. from Vietnam

The oil of Piperpierrei C.DC. (local name Teau nlii, Tieu pierrei - Piper grown on the mountain) was isolated from its aerial parts by hydrodistillation. The oil was analyzed for the first time by high resolution GC, GC/MS and 13C-NMR. It contained more than 80 constituents of which 67 compounds have been identified. The major components were a-methylbenzyl cinnamate (28.0%) and an isomeric methylbenzyl cinnamate (18.1%), esters never found before