The Role of Microbial Communities in the Formation and Decomposition of Soil Organic Matter

Abstract. Soil fungi and bacteria are the key players in the transformation and processing of carbon and nutrients in terrestrial ecosystems, yet controls on their abundance and activity are not well understood. Based on stoichiometric principles, soil microbial processes are expected to be limited by mineral nutrients, which are particularly scarce in often highly weathered tropical forest soils. Such limitation is directly relevant for the fate of soil carbon and global element cycles, but its extent and nature have never been assessed systematically across the tropical biome. Here, we address the relative importance of nitrogen, phosphorus, and other nutrients in limiting soil microbial biomass and process rates in tropical forests. We conducted an in-depth literature review and a meta-analysis of the available nutrient addition experiments in tropical forests worldwide. Our synthesis showed predominant and general phosphorus limitation of a variety of microbial processes across tropical forests, and additional nitrogen limitation in tropical montane forests. The apparent widespread microbial phosphorus limitation needs to be accounted for in the understanding and prediction of biogeochemical cycles in tropical forests and their future functioning. Other mineral nutrients or carbon may modify the importance of phosphorus, but more experimental studies are urgently needed.

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“…, Condron et al. ). This may even be an explanation for some negative effects observed following N additions (Hagedorn et al.…”

Section: Embracing the Complexity Of Soil Microbial Nutrient Limitatimentioning

confidence: 99%

Nutrient limitation of soil microbial processes in tropical forests

Camenzind

Hättenschwiler

Treseder

et al. 2017

Ecological Monographs

307

183

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“…In general, the application of organic amendments such as crop residues and/or farmyard manure increases significantly SOC (Diacono and Montemurro, 2010;Lützow et al, 2006;Maltas et al, 2013), whereas the long-term application of only inorganic fertilizers often has the opposite effect (Edmeades, 2003). The decomposition rate of SOM is influenced by many factors such as (i) the chemical composition and the molecular structure of organic matter (OM) (Kögel-Knabner, 2002); (ii) the physical protection of OM within soil aggregates (Six et al, 2002) and/or (iii) the soil biological activity (Condron et al, 2010). Since processes involved in the accumulation and/or the mineralization of SOM can be particularly slow (Diacono and Montemurro, 2010;Rasmussen et al, 1998), the relative importance of soil properties and farm practices on SOC dynamics should be evaluated in long-term experiments.…”

Section: Introductionmentioning

confidence: 98%

Responses of soil properties and crop yields to different inorganic and organic amendments in a Swiss conventional farming system

Blanchet

Gavazov

Bragazza

et al. 2016

Agriculture, Ecosystems & Environment

146

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In agro-ecosystems, fertilization practices are crucial for sustaining crop productivity. Here, based on a\ud 50-year long-term experiment, we studied the influence of fertilization practices (inorganic and/or\ud organic) and nitrogen (N) application rates on (i) soil physicochemical properties, (ii) microbial and\ud earthworm communities and (iii) crop production. Our results showed that soil organic carbon content\ud was increased by incorporation of crop residues (+2.45%) and farmyard manure application (+6.40%) in\ud comparison to the use of mineral fertilizer alone. In contrast, soil carbon stock was not significantly\ud affected by these fertilization practices. Overall, only farmyard manure application improved soil\ud physicochemical properties compared to mineral fertilization alone. Soil microbial population was\ud enhanced by the application of organic amendments as indicated by microbial biomass and\ud phospholipid-derived fatty acids contents. The fertilization practices and the N application rates\ud affected significantly both the biomass and composition of earthworm populations, especially the epigeic\ud and endogeic species. Finally, farmyard manure application significantly increased crop yield (+3.5%) in\ud comparison to mineral fertilization alone. Crop residue incorporation rendered variable but similar crop\ud yields over the 50-year period. The results of this long-term experiment indicate that the use of organic\ud amendments not only reduces the need for higher amount of mineral N fertilizer but also improves the\ud soil biological properties with direct effects on crop yield

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“…Almost all of the organic C added to soil is derived from plant photosynthesis, and is ultimately returned to the atmosphere as carbon dioxide as a result of microbial respiration (Wolf and Wagner 2005;Condron et al 2010). While it has been shown that amounts of organic C in soil can be substantially altered by shifts in landuse (e.g.…”

Section: Introductionmentioning

confidence: 99%

Effects of long-term fertiliser inputs on the quantities of organic carbon in a soil profile under irrigated grazed pasture

Condron

Black

Wakelin

2012

New Zealand Journal of Agricultural Research

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The long-term fertiliser field trial at Winchmore was used to investigate relationships between pasture production and soil organic carbon (C) storage. In 2009, soil samples to 1 m depth were taken from plots that had been subject to three levels of annual superphosphate fertiliser input for 57 years (nil, 188 kg ha(1 [188PA] and 376 kg ha. Although annual pasture production was 2.4Á2.8 fold higher for the fertiliser treatments compared with nil P, concentrations and amounts of organic C were similar for the various treatments at most soil depths. Furthermore, differences in total quantities of organic C in the soil profile between the nil P (107 t ha (1 ) treatments were not significant. The absence of any significant accumulation of soil organic C in response to increased production was attributed to accelerated decomposition of organic matter inputs linked to a combination of improved pasture quality and increased earthworm activity.

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The Role of Microbial Communities in the Formation and Decomposition of Soil Organic Matter

Cited by 73 publications

References 212 publications

Nutrient limitation of soil microbial processes in tropical forests

Nutrient limitation of soil microbial processes in tropical forests

Responses of soil properties and crop yields to different inorganic and organic amendments in a Swiss conventional farming system

Effects of long-term fertiliser inputs on the quantities of organic carbon in a soil profile under irrigated grazed pasture

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