@article{TranMaiNguyenetal.2018,
  author    = {Tran, C. T. and Mai, N. T. and Nguyen, V. T. and Nguyen, H. X. and Meharg, A. and Carey, M. and Dultz, S. and Marone, F. and Cichy, Sarah Bettina and Nguyen, Minh N.},
  title     = {Phytolith-associated potassium in fern},
  series = {Soil use and Management},
  volume    = {34},
  journal   = {Soil use and Management},
  number    = {1},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0266-0032},
  doi       = {10.1111/sum.12409},
  pages     = {28 -- 36},
  year      = {2018},
  abstract  = {In recent time, phytoliths (silicon deposition between plant cells) have been recognized as an important nutrient source for crops. The work presented here aims at highlighting the potential of phytolith-occluded K pool in ferns. Dicranopteris linearis (D.linearis) is a common fern in the humid subtropical and tropical regions. Burning of the fern D.linearis is, in slash-and-burn regions, a common practice to prepare the soil before planting. We characterised the phytolith-rich ash derived from the fern D.linearis and phytolith-associated potassium (K) (phytK), using X-ray tomographic microscopy in combination with kinetic batch experiments. D.linearis contains up to 3.9g K/kgd.wt, including K subcompartmented in phytoliths. X-ray tomographic microscopy visualized an interembedding structure between organic matter and silica, particularly in leaves. Corelease of K and Si observed in the batch experiments confirmed that the dissolution of ash phytoliths is one of major factors controlling K release. Under heat treatment, a part of the K is made available, while the remainder entrapped into phytoliths (ca. 2.0-3.3\%) is unavailable until the phytoliths are dissolved. By enhanced removal of organic phases, or forming more stable silica phases, heat treatment changes dissolution properties of the phytoliths, affecting K release for crops and soils. The maximum releases of soluble K and Si were observed for the phytoliths treated at 500-800 degrees C. For quantitative approaches for the K provision of plants from the soil phytK pool in soils, factors regulating phytolith dissolution rate have to be considered.},
  language  = {en}
}
@article{KaiserEllerbrockWulfetal.2012,
  author    = {Kaiser, M. and Ellerbrock, Ruth H. and Wulf, M. and Dultz, S. and Hierath, C. and Sommer, M.},
  title     = {The influence of mineral characteristics on organic matter content, composition, and stability of topsoils under long-term arable and forest land use},
  series = {Journal of geophysical research : Biogeosciences},
  volume    = {117},
  journal   = {Journal of geophysical research : Biogeosciences},
  number    = {4},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0148-0227},
  doi       = {10.1029/2011JG001712},
  pages     = {16},
  year      = {2012},
  abstract  = {In this study, we analyzed the influence of soil mineral characteristics (e. g., clay concentration and mineralogical composition, iron and aluminum oxide concentration and crystallinity, specific surface area, and exchangeable cation concentration) on (i) organic carbon (OC) content (kg m(-2)) and (ii) the concentration (g kg(-1)), composition, and stability of the mineral-associated organic matter (OM) of arable and forest topsoils. We selected seven soil types with different mineral characteristics for this study. For each soil type, samples were taken from topsoils of a deciduous forest and an adjacent arable site. The arable and forest sites have been used continuously for more than 100 years. Na-pyrophosphate soluble OM fractions (OM(PY)), representing mineral-associated OM, were extracted, analyzed for OC and C-14 concentrations, and characterized by FTIR spectroscopy. For the forest and arable topsoils, a linear relationship was found between the OC content and exchangeable Ca. For the arable topsoils (pH 6.7-7.5), correlation analyses indicated that the OCPY concentration increased with an increase in oxalate soluble Fe and Al, exchangeable Ca, and Na-pyrophosphate soluble Mg and Fe concentrations. The stability of OM(PY) determined by the C-14 measurements of the near-neutral arable topsoils was shown to increase with the specific surface area and the concentration of exchangeable Ca. For the acidic forest topsoils (pH < 5), the stability of OM(PY) was found to increase as the pH, and the concentration of C=O groups and Na-pyrophosphate soluble Mg increase.},
  language  = {en}
}