Nitrogen transformations and emission of greenhouse gases from three acid soils of humid tropics amended with n sources and moisture regime. II. Nitrous oxide and methane fluxes

Khalil, Mohammad Ibrahim; Boeckx, Pascal; Rosenani, A. B.; Cleemput, Oswald Van

doi:10.1081/css-120000971

Cited by 19 publications

(7 citation statements)

References 42 publications

(31 reference statements)

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“…This is in accordance with findings for temperate forest soils, where the organic layer and SOC rich uppermost mineral layers which immediately show methanogenic activity and net emission of CH 4 if oxygen becomes limited (Saari et al 1997;Butterbach-Bahl and Papen 2002). This indicates that methanogenic activity is ubiquitous in upland soils, especially in C rich microhabitats, supporting active mineralization associated with O 2 consumption and in turn anaerobiosis at the microscale (Khalil et al 2001;Khalil and Baggs 2005).…”

Section: Discussionmentioning

confidence: 78%

Site specific and regional estimates of methane uptake by tropical rainforest soils in north eastern Australia

2008

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Methane flux from rainforest soils in northeast Queensland, Australia, was investigated using a combination of laboratory, field and simulation modelling. In aerobic laboratory incubations, CH 4 uptake in the top 0.1 m of the soil (−2.5 to −7.3 μg CH 4 kg −1 SDW day −1 ) is approximately one order of magnitude higher than CH 4 production under anaerobic conditions. The highest CH 4 uptake, as well as potential CH 4 production is found in the uppermost C rich soil layers. Detailed measurements from three contrasting rainforest sites identified the soils to be functioning as sinks for atmospheric CH 4 . Fifteen months continuous measurement at one of the lowland rainforest sites showed that the seasonality of CH 4 uptake was mainly driven by changes in soil moisture rather than by temperature changes. Maximum CH 4 uptake (109 μg CH 4 m −2 h −1 ) was observed during dry season conditions, whereas during the wet season, CH 4 uptake decreased significantly to near zero. Based on our laboratory experiments and on published literature we developed a semi-empirical CH 4 module for the biogeochemical model ForestDNDCtropica. Tests at several sites showed the robustness of our modelling approach with mean simulated values within 12% of observed values. To estimate regional CH 4 uptake by rainforest soils in the region of the 'Wet Tropics', Queensland, Australia, we linked CH 4 uptake and production algorithms to a regional GIS database. We estimated that the lowland and montane rainforest soils in northeast Queensland, Australia, were a net sink for CH 4 with a mean uptake rate of −2.89 kg CH 4 ha −1 year −1

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Section: Discussionmentioning

confidence: 78%

Site specific and regional estimates of methane uptake by tropical rainforest soils in north eastern Australia

2008

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“…With this, we verified that nitrification did not significantly affect the rhizospheric acidity, supposedly due to the low rates achieved. Other studies also report a low nitrification rate in soil (Khalil, Boeckx, Rosenani, & Cleemput, 2001;Zhao, Cai, & Xu, 2007).…”

Section: Discussionmentioning

confidence: 89%

Effect of Millet Growth, N Sources and Previous Phosphorus Availability on the Efficiency of P Sources

Silva¹,

Mattiello²,

Santos³

et al. 2018

JAS

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The efficiency of phosphate fertilization has been a major challenge for tropical agriculture. Lately, cover plants better adapted to tropical conditions have allowed non-tillage in these areas. Our aim was to investigate the effects of soil and plant (millet) on the efficiency of different P sources combined with N sources in an oxisol with medium and low initial P availability. For this, rhizotubes filled with oxisol under different combinations of P and N source were exposed to the absence and presence of millet plant (Pennisetum glaucum L., Leeke). We characterized the soil before and after, as well the fertilizer sources and plants. There was no effect of medium or low initial P availability in the soil on the P recovery rate (PRR). NH4+ was advantageous mainly combined with a soluble P source, increasing up to 40% the P recovery rate in relation to NO3−. Bayóvar phosphate rock (PR) had higher solubilization than Araxá PR, as well as a significant soil pH increase. Without plants, there was no significant correlation among the variables evaluated, evidencing the plant’s role in dissolving less soluble P sources in an oxisol. Our findings suggest no effect of previous medium P availability on the P recovery rate regardless of phosphorus sources. In addition, an improvement in the P recovery rate when an ammoniacal source is used is observed when soluble phosphate fertilizers are used. Cover plants on oxisols are crucial for increasing the efficiency of phosphorus fertilizers and their plant availability over time.

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“…Consequently, soil organic carbon input increased (Loya et al 2004), resulting in increased available substrate during the green and tillering periods, which further led to higher mean CO 2 flux and higher cumulative CO 2 emission than those from the SR-S treatment. However, the anaerobic conditions (Spormann & Widdel 2000) present after irrigation and the high carbon/nitrogen ratio (Khalil et al 2001) retarded straw decomposition for the entire growing period during spring in the SR-S treatment. Abundant substrate was thereby made available for a longer period, leading to a CO 2 flux peak several days later (first peak), and in the SR-S treatment this led to greater CO 2 mean flux compared to the SR-A treatment in combination with higher cumulative CO 2 emissions during the booting to grain-filling periods.…”

Section: Discussion Co 2 Fluxmentioning

confidence: 95%

Different Responses of Greenhouse Gas Emissions to Straw Application at Different Seasons in Northeast China

Liang¹,

Zhang²

2019

JSM

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Although straw return plays a role in regulating greenhouse gas (GHG) emissions from rice paddy fields, little quantitative information is available on the extent at different periods. In this study, gas samples were collected during the rice growing period from an in-situ experiment comprising three treatments: no straw return (CK); straw return in the autumn (SR-A), and; straw return in the spring (SR-S). The results showed that SR-A and SR-S enhanced CO 2 and CH 4 emissions, but reduced N 2 O emissions during the growing period. The total cumulative CO 2 emissions over the entire growing period in the SR-S treatment reached 20,383.72 kg ha −1 , significantly higher than those of the SR-A and CK treatments. CH 4 emissions for all the growing periods were in the order SR-S > SR-A > CK. The CK and SR-S treatments released the most and least N 2 O during the different periods, respectively. The global warming potential (GWP) of CH 4 released by the SR

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Nitrogen transformations and emission of greenhouse gases from three acid soils of humid tropics amended with n sources and moisture regime. II. Nitrous oxide and methane fluxes

Cited by 19 publications

References 42 publications

Site specific and regional estimates of methane uptake by tropical rainforest soils in north eastern Australia

Site specific and regional estimates of methane uptake by tropical rainforest soils in north eastern Australia

Effect of Millet Growth, N Sources and Previous Phosphorus Availability on the Efficiency of P Sources

Different Responses of Greenhouse Gas Emissions to Straw Application at Different Seasons in Northeast China

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