Plant rhizodeposition: A key factor for soil organic matter formation in stable fractions

Villarino, Sebastián Horacio; Pinto, Priscila; Jackson, Robert B.; Piñeiro, Gervasio

doi:10.1126/sciadv.abd3176

Cited by 217 publications

(115 citation statements)

References 76 publications

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“…Soil biodiversity is linked to soil organic matter (SOM), which composition, and origin are a matter of debate and ongoing studies (2,3). It is accepted that both microbial necromass (4) and plant rhizo-deposition (5) are critical factors in SOM build-up and C sequestration. Both microbial necromass and microbial-derived compounds explain soil mineral-associated (MAOM) and particulate (POM) organic matter aggregation as a result of microbial activity (5).…”

Section: Introductionmentioning

confidence: 99%

“…It is accepted that both microbial necromass (4) and plant rhizo-deposition (5) are critical factors in SOM build-up and C sequestration. Both microbial necromass and microbial-derived compounds explain soil mineral-associated (MAOM) and particulate (POM) organic matter aggregation as a result of microbial activity (5). Soil organic matter (SOM) changes and losses have commonly been associated with soil cultivation, especially conventional agriculture practices (6).…”

Section: Introductionmentioning

confidence: 99%

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Agriculture by Irrigation Modifies Microbial Communities and Soil Functions Associated With Enhancing C Uptake of a Steppe Semi-Arid Soil in Northern Patagonia

et al. 2022

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The transformation of the semiarid steppe soil after 5 years of intensive irrigated agriculture in Northern Patagonia was analyzed in an on-farm study. The private grower venture used conservative practices, including no-till to maintain soil structure, high crop rotation and cover crops. To characterize steppe soil changes by irrigated agriculture, we analyzed the enzymatic activities involved in the biogeochemical cycles (carbon, nitrogen, phosphorus and sulfur), the whole soil fatty acids profile, the state of soil aggregation, and the bacterial and fungal microbiota through DNA sequencing methods. After 5 years of management, irrigated agriculture soil increased organic matter (25–33%), enzymatic activities -Cellobiose-hydrolase (60–250%), Phosphatase (35–60%), Xylanase (101–185%), Aryl-sulphatase (32–100%), Chitinase (85%), β-Glucosidase (61–128%), Leucine-aminopeptidase (138%)—depending on soil series, and macro-aggregate formation at the expense of the abundance of micro-aggregates in the first 0–5 cm of soil. Whole soil fatty acids profiles changed, enhancing mono-unsaturated, branched, cyclic and methylated fatty acids. Microbial communities showed significant differences between irrigated agriculture sites and pristine valleys. The richness-based alpha-diversity established increased bacterial communities but decreased fungal communities in cultivated soil. Indicators selected using the LEfSe method revealed the bacterial taxa Acidothermus, Conexibacter and Thermoleophilum, associated with semiarid steppe soil while Asticcacaulis, Aquicella and Acromobacter with irrigated agriculture. Ascomycota Phylum changed its community composition, being both taxa Aspergillus and Alternaria reduced while Stagonospora and Metarhizium were enhanced in irrigated agriculture. Taxa belonging to Acidobacteria, Chloroflexi, and Betaproteobacteria, that were enriched in irrigated agriculture soils, were associated with higher capture of C but smaller values of aggregation, while taxa abundant on steppe soils belonging to Actinobacteria, Alphaproteobacteria, and Firmicutes were positively associated with soil aggregation but negatively with C uptake.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Agriculture by Irrigation Modifies Microbial Communities and Soil Functions Associated With Enhancing C Uptake of a Steppe Semi-Arid Soil in Northern Patagonia

et al. 2022

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“…Therefore, considering that biodiversity loss is a major driver of reduced multifunctionality across all terrestrial ecosystems (Cardinale et al, 2012;Fanin et al, 2018), biodiversity-based, resilience-oriented farming practices must be targeted if the aim is to restore landscape multifunctionality (Foley et al, 2005(Foley et al, , 2011Kremen and Merenlender, 2018). Alternatives for the re-diversification of agricultural systems with associated gains in ES delivery include the use of diversified crop rotations or polycultures (Kremen and Merenlender, 2018;Bowles et al, 2020;Guzman et al, 2021), cover crops (Pinto et al, 2017;Sekaran et al, 2021;Villarino et al, 2021) and the recoupling of crop and livestock production (Soussana and Lemaire, 2014;Sekaran et al, 2021).…”

Section: Restoring Landscape Multifunctionality: Planned Biodiversity Reconnecting Grazing Animals To Crop Landscapesmentioning

confidence: 99%

Reconnecting Grazing Livestock to Crop Landscapes: Reversing Specialization Trends to Restore Landscape Multifunctionality

Carvalho

Nunes

Pontes-Prates

et al. 2021

Front. Sustain. Food Syst.

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Closely integrated crop and livestock production systems used to be the rule in agriculture before the industrial revolution. However, agricultural landscapes have undergone a massive intensification process in recent decades. This trajectory has led to uniform landscapes of specialized cropping systems or consolidated zones of intensive livestock production. Loss of diversity is at the core of increasing side effects on the environment from agriculture. The unintended consequences of specialization demand the reconciliation of food production with environmental quality. We argue that the reconnection of grazing livestock to specialized crop landscapes can restore decoupled biogeochemical cycles and reintroduce the necessary complexity to restore ecosystem functioning. Besides, the reconnection of crops and livestock promotes several ecosystem services underlying multifunctionality. We focus on the capacity of integrated crop-livestock systems to create biophysical and socioeconomic resilience that cope with weather and market oscillations. We present examples of redesigned landscapes that leverage grazing animals to optimize food production per unit of land while mitigating the externalities of specialized agriculture. We also debate mindset barriers to the shift of current specialization trends toward the design of multifunctional landscapes.

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“…Soil carbon is often considered in terms of distinct soil organic matter "pools": either associated with minerals, occluded within microaggregates, or "free" (not subject to either chemical or physical protection) (Poeplau et al, 2018). Recent studies have shown that labile carbon substrates can play an important role in SOM formation and stabilization in both physically (occluded) and chemically (mineral-associated) pools (Cotrufo et al, 2015;Totsche et al, 2017;Villarino et al, 2021), while plant litter is generally understood to largely comprise the free-light fraction material. The mineral-associated or "heavy fraction" is of particular interest for soil organic carbon persistence; it is typically the oldest distinct pool (Torn et al, 1997) and represents carbon stabilized via mineral sorption and co-precipitation mechanisms (Kogel-Knabner et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…The mineral-associated or "heavy fraction" is of particular interest for soil organic carbon persistence; it is typically the oldest distinct pool (Torn et al, 1997) and represents carbon stabilized via mineral sorption and co-precipitation mechanisms (Kogel-Knabner et al, 2008). This fraction of SOM, commonly termed MAOM (mineral-associated organic matter) (Cotrufo et al, 2019), is largely of microbial origin and thought to be derived from relatively labile C substrates (Clemente et al, 2011;Cotrufo et al, 2013;Villarino et al, 2021). Recent work has suggested that microbial necromass may be a primary precursor to stable organic matter in grasslands (Angst et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Belowground allocation and dynamics of recently fixed plant carbon in a California annual grassland soil

Fossum

Estera-Molina

Yuan

et al. 2021

Preprint

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Plant roots and the organisms that surround them are a primary source for stabilized organic C, particularly in grassland soils, which have a large capacity to store organic carbon belowground. To quantify the flow and fate of plant fixed carbon (C) in a Northern California annual grassland, we tracked plant carbon from a five-day 13CO2 pulse field labeling for the following two years. Soil and plant samples were collected immediately after the pulse labeling, and again at three days, four weeks, six months, one year, and two years. Soil organic matter was fractionated using a sodium polytungstate density gradient to separate the free-light fraction (FLF), occluded-light fraction (OLF), and heavy fraction (HF). Using isotope ratio mass spectrometry, we measured 13C enrichment and total C content for plant shoots, roots, soil, soil dissolved organic carbon (DOC), and the FLF, OLF, and HF. The HF was further analyzed by solid state 13C NMR spectroscopy. At the end of the labeling period, the largest amount of 13C was recovered in plant shoots (60%), but a substantial amount (40%) was already found belowground in roots, soil, and soil DOC. Density fractionation of 4-week soil samples (from which living roots were removed) indicated that the highest isotope enrichment was in the mineral-rich heavy fraction, with similar enrichment of the FLF and OLF. At the 6-month sampling, after the dry summer period during which plants senesced and died, the amount of label in the FLF increased such that it was equal to that in the HF. By the 1-year sampling, 13C in the FLF had declined substantially and continued to decline by the 2-year sampling. 13C recovery in the OLF and HF, however, was qualitatively stable between sampling times. By the end of the 2-year experiment, 69% of remaining label was in the HF, 18% in the FLF and 13% in the OLF. While the total 13C content of the HF did not change significantly from the 4-week to the 2-year sample time, 13C NMR spectroscopic analysis of spring HF samples from 2018, 2019, and 2020 suggests that the relative proportion of aliphatic/alkyl functional groups declined in the newly formed SOC over the 2-year period. Simultaneously, aromatic and carbonyl functional groups increased, and the proportion of carbohydrate groups remained relatively constant. In summary, our results indicate that initial associations between minerals and root-derived organic matter are significant and form rapidly; by 4 weeks, a substantial amount (17%) of the total plant-derived 13C had become associated with the heavy fraction (HF) of soil. While the majority of annual C input cycles rapidly (<2-year timescale), a sizeable proportion (~12% of the original inputs) persisted for 2 years.

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Plant rhizodeposition: A key factor for soil organic matter formation in stable fractions

Cited by 217 publications

References 76 publications

Agriculture by Irrigation Modifies Microbial Communities and Soil Functions Associated With Enhancing C Uptake of a Steppe Semi-Arid Soil in Northern Patagonia

Agriculture by Irrigation Modifies Microbial Communities and Soil Functions Associated With Enhancing C Uptake of a Steppe Semi-Arid Soil in Northern Patagonia

Reconnecting Grazing Livestock to Crop Landscapes: Reversing Specialization Trends to Restore Landscape Multifunctionality

Belowground allocation and dynamics of recently fixed plant carbon in a California annual grassland soil

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