Spatial variations of soil silicon availability and biogenic silicon flux in a lowland tropical forest in Malaysia

Abstract

Tropical tree species differ widely in their silicon (Si) accumulation patterns, but the implications of such species differences for ecosystem Si flux remain unexplored. We analyzed how biogenic Si flux via leaf litter and soil Si availability in the upper soil vary spatially within a 2 ha area in a lowland Dipterocarp forest in Peninsular Malaysia. Silicon concentration per unit leaf dry mass of 86 dominant tree species in this plot ranged from 0.4 to 126 mg/g. Soil Si availability at 100 sampling points and Si flux via leaf litter at 66 litter traps showed large variations up to 3.3‐ and 17.9‐folds, respectively. However, they correlated neither with each other nor with the expected Si flux from tree species composition in the neighborhood. When we classified tree species to four groups by their leaf Si concentrations (negligible, low, moderate and high), tree species with moderate leaf Si concentrations were significantly more abundant on Si‐rich soils. In contrast, the other three groups did not show any significant spatial relationships with soil Si availability. These results indicate that soil Si availability, Si accumulation by vegetation and Si flux via leaf litter show wide spatial variations in a lowland tropical forest, without a simple relationship with each other.

A shift from phenol to silica‐based leaf defences during long‐term soil and ecosystem development

“…5) (Zemunik et al 2015), and other species might benefit from the carboxylate exudation of their neighbours (Lambers et al 2018). This mechanism may also explain why we observed species with some of the highest leaf [Si] found in literature (up to 43 g kg −1 DW for Mesomelaena pseudostygia at stage 4) (Schoelynck et al 2010;Carey et al 2017Carey et al , 2019Schaller et al 2018;Ishizawa et al 2019;Nakamura et al 2019), despite Jurien Bay soils being among the most desilicated worldwide, with one of the lowest Si availability for plants (de Tombeur et al 2020b).…”

“…2018; Ishizawa et al . 2019; Nakamura et al . 2019), despite Jurien Bay soils being among the most desilicated worldwide, with one of the lowest Si availability for plants (de Tombeur et al .…”

Variation of foliar silicon concentrations in temperate forbs: effects of soil silicon, phylogeny and habitat

“…About 20% of the studied forb species can be classified as high-accumulating species (foliar Si > 5 mg g −1 ) and contributed most to the observed interspecific variation in foliar Si concentrations. Previous studies showed similar skewed distributions of Si concentration in dicots, with few high-accumulating and many lowaccumulating species (Schaller et al 2018;Ishizawa et al 2019;Hodson et al 2005;Deshmukh et al 2020). Physiological and ecological benefits of Si in alleviating abiotic and biotic stress, which were initially found in monocots and more recently in dicots (reviewed in Cooke and Leishman 2016;Putra et al 2020), are assumed to be especially pronounced in high accumulators (Ma 2004).…”

Silicon Cycling in Soils Revisited

“…Si cycling ultimately primarily depends on the parent material in terms of mineral composition, with every mineral exhibiting different Si dissolution rates affecting Si availability [ 103 ]. The Si availability of soils is highly heterogenic at the landscape level [ 232 ], which might be due to hydrological effects. However, only a few articles show a larger dataset for Si availability in soils.…”

“…ability [103]. The Si availability of soils is highly heterogenic at the landscape level [232], which might be due to hydrological effects. However, only a few articles show a larger dataset for Si availability in soils.…”