Effect of acetate on soil respiration, N2O emissions and gross N transformations related to fungi and bacteria in a grassland soil

Abstract. Most recently atmospheric studies have evidenced the imprint of large N2O sources in tropical/subtropical lands. This source might be attributed to agricultural areas as well as to natural humid ecosystems. The uncertainty related to both sources is very high, due to the paucity of data and small frequency of sampling in tropical studies. This is particularly relevant for the African continent. The principal objective of this work was to quantify the annual budget of N2O emissions in an African tropical rain forest. Soil N2O emissions were measured over 19 months in Ghana, National Park of Ankasa, in upland and lowland areas, for a total of 119 days of observation. The calculated annual average emission was 2.33 ± 0.20 kg N-N2O ha−1yr−1, taking into account the proportion of upland vs. lowland, as the two areas showed significantly different fluxes, the lowland being characterized by lower N2O emissions. N2O fluxes peaked between June and August and were significantly correlated with soil respiration on a daily and monthly basis. No clear correlation was found in the upland areas between N2O fluxes and soil water content or rain whereas in the lowland soil water content concurred with soil respiration in determining N2O flux variability. The N2O source strength calculated in this study, very close to those reported for the other two available studies in African rain forests and to the estimated mean derived from worldwide studies in humid tropical forests (2.96 ± 2.0 kg N-N2O ha−1 yr−1), supports the concept that tropical humid forests represent the strongest natural source of N2O emissions, most probably the strongest source of N2O in the African continent.

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Pure stands of temperate forest tree species modify soil respiration and N turnover

Biogeosciences Discussions ◽

10.5194/bgd-2-303-2005 ◽

2005 ◽

Vol 2 (2) ◽

pp. 303-331 ◽

Cited By ~ 24

Author(s):

N. Brüggemann ◽

P. Rosenkranz ◽

H. Papen ◽

K. Pilegaard ◽

K. Butterbach-Bahl

Keyword(s):

Soil Respiration ◽

Tree Species ◽

N Mineralization ◽

Forest Type ◽

Organic Layer ◽

Pedunculate Oak ◽

Gross Nitrification ◽

N Transformations ◽

Soil C ◽

Gross N Mineralization

Abstract. The effects of five different tree species common in the temperate zone, i.e. beech (Fagus sylvatica L.), pedunculate oak (Quercus robur L.), Norway spruce (Picea abies [L.] Karst), Japanese larch (Larix leptolepis [Sichold and Zucc.] Gordon) and mountain pine (Pinus mugo Turra), on soil respiration, gross N mineralization and gross nitrification rates were investigated. Soils were sampled in spring and summer 2002 at a forest trial in Western Jutland, Denmark, where pure stands of the five tree species of the same age were growing on the same soil. Soil respiration, gross rates of N mineralization and nitrification were significantly higher in the organic layers than in the Ah horizons for all tree species and both sampling dates. In summer (July), the highest rates of soil respiration, gross N mineralization and gross nitrification were found in the organic layer under spruce, followed by beech > larch > oak > pine. In spring (April), these rates were also higher under spruce compared to the other tree species, but were significantly lower than in summer. For the Ah horizons no clear seasonal trend was observed for any of the processes examined. A linear relationship between soil respiration and gross N mineralization (r2=0.77), gross N mineralization and gross nitrification rates (r2=0.72), and between soil respiration and gross nitrification (r2=0.81) was found. The results obtained underline the importance of considering the effect of forest type on soil C and N transformations.

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In situ changes in gross N transformations in bare soil after addition of straw

Soil Biology and Biochemistry ◽

10.1016/s0038-0717(98)00113-8 ◽

1998 ◽

Vol 31 (1) ◽

pp. 119-133 ◽

Cited By ~ 77

Author(s):

Sylvie Recous ◽

Celso Aita ◽

Bruno Mary

Keyword(s):

Bare Soil ◽

N Transformations ◽

Gross N Transformations

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The influence of soil fertility on carbon cycling and storage in temperate tree bioenergy crops

10.5194/egusphere-egu2020-3686 ◽

2020 ◽

Author(s):

Leigh-Anne Kemp

Keyword(s):

Soil Respiration ◽

Carbon Cycling ◽

Tree Species ◽

Mycorrhizal Fungi ◽

Community Dynamics ◽

Block Design ◽

Nitrogen Fertilizers ◽

Bioenergy Crops ◽

N2o Emissions ◽

And Storage

LA Kemp, Supervisors: A. Karley, A. Bennett, A. Taylor, N. McNamara, E.J SayerShort &#8211; rotation woody perennials such as Populus and Salix are often selected for bioenergy crops in temperate climates. In conjunction with providing a renewable crop, bioenergy crops can improve carbon storage in previously degraded soils and associate with beneficial mycorrhizal fungi. Applying nitrogen fertilizers to bioenergy crops can increase yield and carbon sink but may also increase CO2 emissions through increased soil respiration and N2O through increased microbial activity which alter population and community dynamics.Changing environmental conditions due to climate change such as prolonged droughting and increasing intensity of rewetting are also impacting plant-soil interactions. However, there are gaps in the understanding of the mechanisms responsible for plant responses to changing abiotic conditions. Therefore, the scale of future carbon cycling, CH4 and N2O emissions by temperate tree species are still very unclear.To address this my experiment, focuses on two temperate tree species used in bioenergy production known to associate with mycorrhizal fungi. The study will run over two growing seasons, using a randomized block design with four fungal treatments, four nutrient treatments and then implementing two abiotic treatments during the second growing season. I aim to determine how soil nutrient availability influences: i) plant &#8211; mycorrhiza associations, ii) plant carbon cycling and storage, iii) soil respiration rates, iv) plant and soil GHG emission rates. v) carbon cycling and GHG emissions under different climate controls.

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