TY  - JOUR
A1  - Tran, C. T.
A1  - Mai, N. T.
A1  - Nguyen, V. T.
A1  - Nguyen, H. X.
A1  - Meharg, A.
A1  - Carey, M.
A1  - Dultz, S.
A1  - Marone, F.
A1  - Cichy, Sarah Bettina
A1  - Nguyen, Minh N.
T1  - Phytolith-associated potassium in fern
BT  - characterization, dissolution properties and implications for slash-and-burn agriculture
JF  - Soil use and Management
N2  - 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.
KW  - Potassium
KW  - phytolith
KW  - fern
KW  - Dicranopteris linearis
Y1  - 2018
U6  - https://doi.org/10.1111/sum.12409
SN  - 0266-0032
SN  - 1475-2743
VL  - 34
IS  - 1
SP  - 28
EP  - 36
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Kaiser, M.
A1  - Ellerbrock, Ruth H.
A1  - Wulf, M.
A1  - Dultz, S.
A1  - Hierath, C.
A1  - Sommer, M.
T1  - The influence of mineral characteristics on organic matter content, composition, and stability of topsoils under long-term arable and forest land use
JF  - Journal of geophysical research : Biogeosciences
N2  - 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.
Y1  - 2012
U6  - https://doi.org/10.1029/2011JG001712
SN  - 0148-0227
VL  - 117
IS  - 4
PB  - American Geophysical Union
CY  - Washington
ER  -