CO2 efflux by rapid decomposition of low molecular organic substances in soils

Kuzyakov, Yakov; Демин, В. В.

doi:10.1007/s10112-998-0002-2

Cited by 39 publications

(28 citation statements)

References 22 publications

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“…3 g,h). This clearly implies that rapid decomposition of glycine occurred in soils as observed by other studies (Kuzyakov and Demin 1998;Jones 1999), providing available 15 NH þ 4 or 15 NO À 3 for plant uptake. As a result, the contribution of organic N to plants might be strongly overestimated by using The rapid mineralization of glycine and the rapid nitrification of ammonium (Fig.…”

Section: Discussionsupporting

confidence: 79%

“…15 N-glycine uptake was very similar to 15 NH þ 4 uptake by maize seedlings under the two light conditions. This might be explained by rapid decomposition of glycine by microorganisms to inorganic N (Kuzyakov and Demin 1998;Jones 1999;Jones and Kielland 2002;Nordin et al 2004) and thereafter uptake of 15 N from glycine in the form of NH þ 4 or NO À 3 4 h following tracer addition. In this study we didn't determine the rate of glycine turnover in the soil.…”

Section: Discussionmentioning

confidence: 99%

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Light affects competition for inorganic and organic nitrogen between maize and rhizosphere microorganisms

Stange

Richter

et al. 2007

Plant Soil

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Light affects competition for inorganic and organic nitrogen between maize and rhizosphere microorganisms

Stange

Richter

et al. 2007

Plant Soil

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“…This substitution is valid because low molecular weight sugars are the main component of root exudates (Jones and Darrah, 1993;Merbach et al, 1999). The other components of rhizodeposits-carboxylic acids, amino acids, etc.-have similar microbial availability as sugars (Kuzyakov and Demin, 1998). Originally (Swinnen, 1994), 12 C glucose solution was used as one variant.…”

Section: Model Rhizodeposition Methodsmentioning

confidence: 99%

Separating microbial respiration of exudates from root respiration in non-sterile soils: a comparison of four methods

Kuzyakov

2002

Soil Biology and Biochemistry

143

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Partitioning the root-derived CO 2 efflux from the soil into actual root respiration (RR) and microbial respiration of exudates and root residues is very important for determining the carbon (C) and energy balance of soils. Studies based on artificial root environments like hydroponics or sterile soils give unrealistic figures for C partitioning and are unsuitable for predicting C flows under natural conditions. To date, only four methods have been suggested to separate RR and rhizomicrobial respiration in non-sterile soils: (1) the isotope dilution method, (2) the model rhizodeposition technique, (3) modeling of 14 CO 2 efflux dynamics, and (4) the exudate elution procedure. All four methods are based on the pulse labeling of shoots in a 14 CO 2 atmosphere and subsequent monitoring of 14 CO 2 efflux from the soil. However, the basic assumptions and principles of these methods, as well as the results observed in the original papers, all differ from one another. This study describes the separation of RR of Lolium perenne grown on a loamy Haplic Luvisol from microbial respiration of rhizodeposits by means of all four methods under the same experimental conditions.In spite of alternative principles, the isotope dilution and the 14 CO 2 dynamics methods show a similar level of RR: accordingly, 39 and 45% of total root-derived CO 2 efflux were accounted for by RR. The remainder is rhizomicrobial respiration. The exudate elution method, which underestimates the total rhizodeposition, shows that at least 19% of root-derived CO 2 is produced by exudate decomposition. The microbial respiration of rhizodeposits calculated using the model rhizodeposition technique is also underestimated. The exudate elution method is the only procedure allowing physical separation of both C flows. The assumptions and principles of all four methods are reviewed and the effects of possible shortcomings on the separation results are discussed. In conclusion, RR contributes about 40 -50% to the rootderived CO 2 efflux. The remaining 50 -60% comprise the microbial decomposition of root exudates and other rhizodeposits. The longer the period of monitoring the CO 2 efflux after the pulse labeling is, the higher the contribution of rhizomicrobial respiration to the total rootderived CO 2 efflux from soil. q

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“…The rhizosphere can also be a source of carbon dioxide through the decomposition of soil organic matter, as most of the root exudates are oxidized to carbon dioxide within a few hours (Jones and Hodge 1999;Kuzyakov and Demin 1998). Therefore, both plant productivity and soil organic carbon dynamics can be influenced indirectly by the labile carbon fractions occurring in the plant rhizosphere zone (Kant et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Soil labile organic carbon fractions in rhizosphere soil in citrus plantations in the Three Gorges Reservoir Area

et al. 2015

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Rhizosphere carbon sequestration plays a crucial role in soil carbon dynamics. Little information is available on the dynamics of rhizosphere soil labile organic carbon fractions compared with bulk soil at different citrus stand age. Two replicate sites of three stand ages (10-, 20-, and 30-year) of citrus in the Three Gorges Reservoir area of China were studied. The results showed that rhizosphere soil organic carbon has an increases of 18.76 % under 20-year stand and 11.09 % under 30-year stand compared with bulk soil (P \ 0.05), respectively. The dissolved organic C of rhizosphere soil was 31.32, 19.57 and 31.81 % higher compared with bulk soil under 10-, 20-to 30-year stands (P \ 0.05), respectively, whereas readily oxidizable organic C (ROC) was 50.47, 70, and 64.54 % higher (P \ 0.05). Microbial biomass (MBC) and water-soluble carbohydrate (WSCh) had no significant difference between rhizosphere and bulk soils in the 10-and 20-year stands, whereas a 9.88 % lower for MBC and a 36.47 % higher for WSCh in rhizosphere soil compared with bulk soil under 30-year stand were found (P \ 0.05). Rhizosphere soil respiration showed a significantly negative relationship with ROC (r = 0.51, P \ 0.05), WSCh (r = 0.60, P \ 0.01) and MBC (r = 0.68, P \ 0.01). The effect of the citrus rhizosphere on measured soil labile organic carbon fractions differed for each citrus stand age.

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CO2 efflux by rapid decomposition of low molecular organic substances in soils

Cited by 39 publications

References 22 publications

Light affects competition for inorganic and organic nitrogen between maize and rhizosphere microorganisms

Light affects competition for inorganic and organic nitrogen between maize and rhizosphere microorganisms

Separating microbial respiration of exudates from root respiration in non-sterile soils: a comparison of four methods

Soil labile organic carbon fractions in rhizosphere soil in citrus plantations in the Three Gorges Reservoir Area

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