Phytolith-associated potassium in fern

characterization, dissolution properties and implications for slash-and-burn agriculture

authored by: Chin T. Tran, N. T. Mai, Van Thanh A. Nguyen, A. Meharg, M. Carey, Stefan Dultz, Federica Marone, Sarah B. Cichy, Minh Ngoc Nguyen, Huan Huu Nguyen
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 3.9 g K/kg d.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 °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.
Organisation(s): Institute of Soil Science
Section Soil Chemistry
External Organisation(s): Vietnam National University
Ha Tay Community College (HTCC)
Queen's University Belfast
Paul Scherrer Institut (PSI)
University of Potsdam
Type: Article
Journal: Soil Use and Management
Volume: 34
Pages: 28-36
No. of pages: 9
ISSN: 0266-0032
Publication date: 27.03.2018
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Agronomy and Crop Science, Soil Science, Pollution
Sustainable Development Goals: SDG 2 - Zero Hunger
Electronic version(s): https://pureadmin.qub.ac.uk/ws/files/148837918/Manuscript_without_changes_marked.pdf (Access: Open)
https://doi.org/10.1111/sum.12409 (Access: Closed)