Research & Domain Knowledge
Proximal sensing
Proximal sensing is one of the most important branches in the field of smart agriculture. My research focuses on combining two devices: portable X-ray fluorescence spectrometry (pXRF) and visible and near-infrared spectrometer (VisNIR). We applied machine learning algorithms to build models to predict soil properties with high efficiency with both sensors. Portable XRF can quantify the elemental concentration of soils, and VisNIR detects the reflectance spectrum in the range of 350-2500 nm, which contains features of iron oxides, functional groups of organic matter, and phyllosilicate. Specifically, we are investigating the interpretability of machine learning models by incorporating knowledge of pedogenesis. Hence, we selected podzolic soils that possess clear migration of Fe/Al organometallic complexes as study subjects. The results have been published in the journal Geoderma titled “Using pXRF and Vis-NIR for characterizing diagnostic horizons of fine-textured podzolic soils in subtropical forests (https://doi.org/10.1016/j.geoderma.2023.116582).”
Podzolization
The podzolization process refers to a complex pedogenesis pathway, which involves the translocation of organic matter and sesquioxides (e.g. Fe2O3 and Al2O3) from eluvial horizons to illuvial horizons. The eluvial horizons (usually called E horizons) typically present white colors due to leaching. On the other hand, the illuvial horizons (B horizons) are characterized by dark-reddish colors because of the accumulation of organometallic complexes, called spodic materials. If the accumulation reaches a certain degree, the soils are classified as Spodosols. The accumulation of spodic material in Spodosols results in higher organic carbon content compared to other soils, and it’s one of the reasons that Spodosols are important. Our research is dedicated to elucidating the process and formation of Spodosols with fine texture in central Taiwan. Our results have been published in the journal Geoderma! You can see interesting outcomes in our publication “Differentiation of fine-textured podzolic soils controlled by climate and landscape in Taiwan (https://doi.org/10.1016/j.geoderma.2022.116155).” A pdf file of the article can be found here.
Micromorphology
Soil micromorphology is a fascinating field of study! We collect Kubiena Boxes in the field to obtain soils in their natural structure, embedded with resin and sliced into thin sections. Thin sections are observed under a polarized light microscope to find the birefringent fabric (b-fabric). The beauty of thin sections is that we get to explore features such as oriented clay coatings and minerals while delving deep into the past of the soils. It is by beholding the tiniest components of soils, we find evidence of the complex pedogenesis process.
Silicon availability
My undergraduate project was mainly about silicon (Si) availability in the paddy fields and forests in Taiwan. I conducted physiochemical analysis on soils and extract the plant-available Si using acetate buffer. In the study, we found available Si is controlled by pH, clay, and Fe/Al oxides, and paddy rice cultivation resulted in the depletion of available Si. You can find the results of this study in my publication “Silicon availability in relation to soil properties in Inceptisols on uncultivated lands and paddy fields in Taiwan (https://doi.org/10.1016/j.geodrs.2021.e00406).” A pdf file of the article can be found here.
Anthropology
When I was a sophomore, I started to have continuous cooperation between my laboratory and the Department of Anthropology, NTU. The site we are focusing on is the Hutoushan Park site from Linkou Terrace, Taiwan. The Hutoushan Park site belongs to the Botanical Garden Culture of the Late Neolithic Period, and it’s believed to last approximately from 2,800~1,800 BP. My participation was mainly assisting soil analysis, and it was such a cool experience to see people studying archaeology in soil pits. The way we see soil profiles are different, and our interpretations are different. Until now, the exchange of ideas keeps giving me a lot of pleasure.