Increased silicon concentration in fen peat leads to a release of iron and phosphate and changes in the composition of dissolved organic matter

Self Cite

149

Silicon (Si) speciation and availability in soils is highly important for ecosystem functioning, because Si is a beneficial element for plant growth. Si chemistry is highly complex compared to other elements in soils, because Si reaction rates are relatively slow and dependent on Si species. Consequently, we review the occurrence of different Si species in soil solution and their changes by polymerization, depolymerization, and condensation in relation to important soil processes. We show that an argumentation based on thermodynamic endmembers of Si dependent processes, as currently done, is often difficult, because some reactions such as mineral crystallization require months to years (sometimes even centuries or millennia). Furthermore, we give an overview of Si reactions in soil solution and the predominance of certain solid compounds, which is a neglected but important parameter controlling the availability, reactivity, and function of Si in soils. We further discuss the drivers of soil Si cycling and how humans interfere with these processes. The soil Si cycle is of major importance for ecosystem functioning; therefore, a deeper understanding of drivers of Si cycling (e.g., predominant speciation), human disturbances and the implication for important soil properties (water storage, nutrient availability, and micro aggregate stability) is of fundamental relevance.

Section: Importance Of Si For Crop Productionmentioning

confidence: 99%

Silicon Cycling in Soils Revisited

Schaller

Puppe

Kaczorek

et al. 2021

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149

“…Most recently, it was shown that the effect of Si stimulating respiration of organic matter is only occurring under oxic conditions, whereas under long-term reduced conditions, no effect was found [398]. This effect of Si increasing soil respiration under oxic conditions may be explained by the fact that Si increases P concentrations in soil pore water [83,398,399] and with this the nutrient availability for the microbial decomposer community. Furthermore, it was shown that an increase of Si in soil pore water might also be able to mobilize carboxylic groups from soil organic matter particles, hence potentially additionally increasing litter decomposition [399].…”

Section: Effects On Biogeochemical Cycles 631 the Ecosystem Scalementioning

confidence: 99%

“…This effect of Si increasing soil respiration under oxic conditions may be explained by the fact that Si increases P concentrations in soil pore water [83,398,399] and with this the nutrient availability for the microbial decomposer community. Furthermore, it was shown that an increase of Si in soil pore water might also be able to mobilize carboxylic groups from soil organic matter particles, hence potentially additionally increasing litter decomposition [399]. Another potential explanation for how Si is accelerating organic matter respiration is by a change in soil microbial decomposer community, as shown for reed litter decay-where Si reduced the concentration of ergosterol as a measure of sporulating fungi [395]-and for rice litter-where the abundance of increase in saprotrophic fungi increased with increasing Si availability [396].…”

Section: Effects On Biogeochemical Cycles 631 the Ecosystem Scalementioning

confidence: 99%

Silicon in the Soil–Plant Continuum: Intricate Feedback Mechanisms within Ecosystems

Katz

Puppe

Kaczorek

et al. 2021

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Plants’ ability to take up silicon from the soil, accumulate it within their tissues and then reincorporate it into the soil through litter creates an intricate network of feedback mechanisms in ecosystems. Here, we provide a concise review of silicon’s roles in soil chemistry and physics and in plant physiology and ecology, focusing on the processes that form these feedback mechanisms. Through this review and analysis, we demonstrate how this feedback network drives ecosystem processes and affects ecosystem functioning. Consequently, we show that Si uptake and accumulation by plants is involved in several ecosystem services like soil appropriation, biomass supply, and carbon sequestration. Considering the demand for food of an increasing global population and the challenges of climate change, a detailed understanding of the underlying processes of these ecosystem services is of prime importance. Silicon and its role in ecosystem functioning and services thus should be the main focus of future research.

“…Furthermore, exogenous Si also was proved to contribute to the increased P activization from Fe-P phases on mineral surfaces [ 94 , 95 ]. Many studies have shown that the increased soil P availability under high Si can be explained by Si competition with P for binding at the surface of soil minerals resulting in P mobilization [ 96 , 97 , 98 , 99 , 100 , 101 , 102 ]. Several studies suggest that the competitive ability of Si against P may be pH-dependent [ 21 , 103 , 104 , 105 ].…”

Section: Mechanisms Of Si Alleviation Of P-deficiency Stress In Plmentioning

confidence: 99%

Role of Silicon in Mediating Phosphorus Imbalance in Plants

Qin

et al. 2020

The soil bioavailability of phosphorus (P) is often low because of its poor solubility, strong sorption and slow diffusion in most soils; however, stress due to excess soil P can occur in greenhouse production systems subjected to high levels of P fertilizer. Silicon (Si) is a beneficial element that can alleviate multiple biotic and abiotic stresses. Although numerous studies have investigated the effects of Si on P nutrition, a comprehensive review has not been published. Accordingly, here we review: (1) the Si uptake, transport and accumulation in various plant species; (2) the roles of phosphate transporters in P acquisition, mobilization, re-utilization and homeostasis; (3) the beneficial role of Si in improving P nutrition under P deficiency; and (4) the regulatory function of Si in decreasing P uptake under excess P. The results of the reviewed studies suggest the important role of Si in mediating P imbalance in plants. We also present a schematic model to explain underlying mechanisms responsible for the beneficial impact of Si on plant adaption to P-imbalance stress. Finally, we highlight the importance of future investigations aimed at revealing the role of Si in regulating P imbalance in plants, both at deeper molecular and broader field levels.