Assimilate translocation to the rhizosphere of two wheat lines and subsequent utilization by rhizosphere microorganisms at two soil nitrogen concentrations

Liljeroth, Erland; Veen, Johannes A. van; Miller, H. J.

doi:10.1016/0038-0717(90)90026-v

Cited by 178 publications

(104 citation statements)

References 31 publications

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“…This would partly explain the negative relationships found between both N 2 O production and denitrification rates and soil WSOC contents. Indeed, a lack of available mineral N can decrease the capacity of soil heterotrophs to use soluble organic C (Merckx et al 1987;Liljeroth et al 1990). On the same experimental plots, Chantigny et al (1998) have found that soil WSOC accumulated in soil at low mineral N contents, suggesting that this C source was less degraded by microbes as available N decreased in soil.…”

Section: Nitrogen Gas Production In Relation To Soilmentioning

confidence: 99%

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Nitrous oxide production in soils cropped to corn with varying N fertilization

Chantigny¹,

Prévost²,

Angers³

et al. 1998

Can. J. Soil. Sci.

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. 1998. Nitrous oxide production in soils cropped to corn with varying N fertilization. Can. J. Soil Sci. 78: [589][590][591][592][593][594][595][596]. Mineral N fertilizers may contribute to N gas emissions to the atmosphere. Soil cores were collected in 1993 and 1994, in a sandy loam and a sandy clay cropped with an early-maturing corn (Zea mays L.) hybrid and fertilized with ammonium nitrate at rates of 10, 60, 120 or 180 kg N ha -1 . Denitrification and N 2 O production rates, air-filled porosity (AFP), water-soluble mineral N (WSMN) and water-soluble organic C (WSOC) were measured. Denitrification and N 2 O production rates were generally small, but values >2 µg N 2 O-N kg -1 h -1 were measured (i) when WSMN contents exceeded 5 mg kg -1 , and (ii) when AFP was <50 to 55% in the sandy loam, and <40 to 45% in the sandy clay. For most sampling dates, N 2 O production and denitrification rates increased with N fertilizer level. In 1993, AFP was relatively high and variable in soil cores, and regression analyses revealed that denitrification rates were closely related to AFP. In 1994, AFP was relatively low in soil cores, and regression analyses showed that denitrification and N 2 O production rates were positively related to WSMN and negatively to WSOC. It is suggested that provided AFP was low, N fertilization may have had either a direct effect on denitrification and N 2 O production rates by determining WSMN availability to microorganisms, or an indirect effect by affecting WSOC metabolism in soil. Depending on the year and soil type, mean denitrification rates were 40 to 130% greater in the soil with 180 than with 120 kg N ha -1 . Corresponding N 2 O production rates were 50 to 200% higher in the 180 than in the 120 kg N ha -1 treatment. It appears that limiting N fertilizer to 120 kg ha -1 , under early-maturing corn production, may prevent excessive gaseous N losses due to denitrification. Il semble que, lorsque la POA était faible, le fertilisant azoté a eu un effect direct sur la dénitri-fication et la production de N 2 O en conditionnant la disponibilité de l'AMH. Le fertilisant aurait aussi eu un effet indirect en affectant le métabolisme du COH. Selon l'année et le type de sol, les taux moyens de dénitrification ont été de 40 à 130 % supérieurs dans les sols recevant 180 que dans ceux recevant 120 kg N ha -1 . Les taux de production de N 2 O ont été de 50 à 200 % supérieurs dans les parcelles avec 180 que dans celles avec 120 kg N ha -1 . Sous une culture de maïs hâtif, restreindre la fertilisation à 120 kg N ha -1 permettrait d'éviter des pertes excessives d'azote causées par la dénitrification.

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Section: Nitrogen Gas Production In Relation To Soilmentioning

confidence: 99%

“…A lack of mineral N may also decrease the capacity of microorganisms to use soluble organic C (Merckx et al 1987;Liljeroth et al 1990), and thus could indirectly reduce the capacity of denitrifiers and heterotrophic nitrifiers to produce N gases.…”

mentioning

confidence: 99%

Nitrous oxide production in soils cropped to corn with varying N fertilization

Chantigny¹,

Prévost²,

Angers³

et al. 1998

Can. J. Soil. Sci.

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“…Accumulated evidence suggests that a big proportion of root exudates is utilized and released as CO 2 in a very short period of time; only a small portion becomes microbial biomass (Dyer et al 1991;Harris and Paul 1991). The microbial assimilation efficiency of these exudates (6.5-15%; Helal and Sauerbeck 1989;Liljeroth et al 1990;Martin and Merckx 1992), is considerably lower than the theoretical maximum of 60 percent (Payne 1970) and of other sources of carbon in the soil. The microbial assimilation efficiency is 61 percent for glucose added to the soil after about 40 hours of incubation (Elliott et al 1983), 27 percent after 61 weeks of incubation (Johansson 1992), and 47 percent for rye shoots added to the soil after 7 weeks of incubation (Cheng and Coleman 1990).…”

Section: Microbial Assimilation Efficiency Of Rhizodepositsmentioning

confidence: 98%

“…If a large proportion of root exudates is used by diazotrophs in the rhizosphere, the assimilation efficiency of root exudates will be much lower than if it is being used by non-nitrogen-fixing microbes. Several studies (Liljeroth et al 1990;Van Veen et al 1991) have shown that the assimilation efficiency of root-derived materials is higher when more nitrogen fertilizer has been used. It is likely that nitrogen fertilization suppresses diazotrophic activity in the rhizosphere, which contributes to higher assimilation efficiency.…”

Section: Microbial Assimilation Efficiency Of Rhizodepositsmentioning

confidence: 99%

“…Because of the abundant supply of available carbon in the form of exudates, microbial growth in the rhizosphere may be highly limited by mineral nutrients. For example, microbial respiration rate in the young wheat rhizosphere is not stimulated by addition of glucose (Cheng et al 1994), but the assimilation efficiency of root-derived materials is higher when more nitrogen fertilizer has been used (Liljeroth et al 1990;Van Veen et al 1991).…”

Section: Microbial Assimilation Efficiency Of Rhizodepositsmentioning

confidence: 99%

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Carbon Fluxes in the Rhizosphere

Cheng¹,

Gershenson²

2007

The Rhizosphere

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Review: Factors affecting rhizosphere priming effects

Kuzyakov

2002

Z. Pflanzenernähr. Bodenk.

911

525

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Living plants change the local environment in the rhizosphere and consequently affect the rate of soil organic matter (SOM) decomposition. The rate may increase for 3‐ to 5‐folds, or decrease by 10 % to 30 % by plant cultivation. Such short‐term changes of rate (intensity) of SOM decomposition are due to the priming effect. In the presence of plants, a priming effect occurs in the direct vicinity of the living roots, and it is called rhizosphere priming effect (RPE). Plant‐mediated and environmental factors, such as, plant species, development stage, soil organic matter content, photosynthesis intensity, and N fertilization which affect RPE are reviewed and discussed in this paper. It was concluded that root growth dynamics and photosynthesis intensity are the most important plant‐mediated factors affecting RPE. Environmental factors such as amount of decomposable C in soil and Nmin content are responsible for the switch between following mechanisms of RPE: concurrence for Nmin between roots and microorganisms, microbial activation or preferential substrate utilization. Succession of mechanisms of RPE along the growing root in accordance with the rhizodeposition types is suggested. Different hypotheses for mechanisms of filling up the C amount loss by RPE are suggested. The ecosystematic relevance of priming effects by rhizodeposition relates to the connection between exudation of organic substances by roots, the increase of microbial activity in the rhizosphere through utilization of additional easily available C sources, and the subsequent intensive microbial mobilization of nutrients from the soil organic matter.

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Assimilate translocation to the rhizosphere of two wheat lines and subsequent utilization by rhizosphere microorganisms at two soil nitrogen concentrations

Cited by 178 publications

References 31 publications

Nitrous oxide production in soils cropped to corn with varying N fertilization

Nitrous oxide production in soils cropped to corn with varying N fertilization

Carbon Fluxes in the Rhizosphere

Review: Factors affecting rhizosphere priming effects

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