Fluxes of nitrous oxide from boreal peatlands as affected by peatland type, water table level and nitrification capacity

Land-use change in tropical peatlands substantially impacts emissions of methane (CH4) and nitrous oxide (N2O) in addition to emissions of carbon dioxide (CO2). However, assessments of peat GHG budgets are scarce and the contributions of CH4 and N2O remain highly uncertain. The objective of our research was to assess changes in peat GHG flux and budget associated with peat swamp forest disturbance and conversion to oil palm plantation and to evaluate drivers of variation in trace gas fluxes. Over a period of one and a half year, we monitored monthly CH4 and N2O fluxes together with environmental variables in three undrained peat swamp forests and three oil palm plantations on peat in Central Kalimantan. The forests included two primary forests and one 30-year-old secondary forest. We calculated the peat GHG budget in both ecosystems using soil respiration and litterfall rates measured concurrently with CH4 and N2O fluxes, site-specific soil respiration partitioning ratios, and literature-based values of root inputs and dissolved organic carbon export. Peat CH4 fluxes (kg CH4 ha-1 yr-1) were insignificant in oil palm (0.3 &#177; 0.4) while emissions in forest were high (14.0 &#177; 2.8), and larger in wet than in dry months. N2O emissions (kg N2O ha-1 yr-1) were highly variable spatially and temporally and similar across land-uses (5.0 &#177; 3.9 and 5.2 &#177; 3.7 in oil palm and forest). Temporal variation of CH4 was controlled by water table level and soil water-filled pore space in forest and oil palm, respectively. Monthly fluctuations of N2O were linked to water table level in forest. The peat GHG budget (Mg CO2 equivalent ha-1 yr-1) in oil palm (31.7 &#177; 8.6) was nearly eight times the budget in forest (4.0 &#177; 4.8) owing mainly to decreased peat C inputs and increased peat C outputs. The GHG budget was also ten times higher in the secondary forest (10.2 &#177; 4.5) than in the primary forests (0.9 &#177; 3.9) on the account of a larger peat C budget and N2O emission rate. In oil palm 96% of emissions were released as CO2 whereas in forest CH4 and N2O together contributed 65% to the budget. Our study highlights the disastrous atmospheric impact associated with forest degradation and conversion to oil palm in tropical peatlands and stresses the need to investigate GHG fluxes in disturbed undrained lands.

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Relationship Between Botanical Composition, Nitrogen Response, and Water Table Level on Wet Meadow Sod 1

Agronomy Journal ◽

10.2134/agronj1959.00021962005100090017x ◽

1959 ◽

Vol 51 (9) ◽

pp. 562-565

Author(s):

M. G. Klages ◽

J. A. Asleson

Keyword(s):

Water Table ◽

Botanical Composition ◽

Nitrogen Response ◽

Wet Meadow ◽

Water Table Level

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Automatic Control of Water Table Level in Soil Tanks

Soil Science Society of America Journal ◽

10.2136/sssaj1968.03615995003200040048x ◽

1968 ◽

Vol 32 (4) ◽

pp. 596-598

Author(s):

C. R. Willey

Keyword(s):

Automatic Control ◽

Water Table ◽

Water Table Level

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The biology of two species of Engaeus (Decapoda : Parastacidae) in Tasmania. III. Habitat, food, associated fauna and distribution

Marine and Freshwater Research ◽

10.1071/mf9770095 ◽

1977 ◽

Vol 28 (1) ◽

pp. 95 ◽

Cited By ~ 25

Author(s):

PJ Suter ◽

AMM Richardson

Keyword(s):

Dissolved Oxygen ◽

Geographical Distribution ◽

Water Table ◽

Freshwater Crayfish ◽

Associated Fauna ◽

Water Table Level ◽

Burrow Structure ◽

Study Sites ◽

North Western ◽

Temperature Water

The habitats of two apparently sympatric freshwater crayfish, Engaeus cisternarius and E. fossor, in north-western Tasmania were compared. At two study sites data on rainfall, temperature, water table level, dissolved oxygen and pH were collected. E. fossor occupies regions below the water table, whilst E. cisternarius occupies drier areas above the water table. The burrow structure, burrow fauna, ectofauna and food were compared. The geographical distribution of each species is discussed.

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