 |
| Titel |
Spatial and temporal effects of drought on soil CO2 efflux in a cacao agroforestry system in Sulawesi, Indonesia |
| VerfasserIn |
O. Straaten, E. Veldkamp, M. Köhler, I. Anas |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 4 ; Nr. 7, no. 4 (2010-04-09), S.1223-1235 |
| Datensatznummer |
250004662
|
| Publikation (Nr.) |
 copernicus.org/bg-7-1223-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| Climate change induced droughts pose a serious threat to ecosystems across
the tropics and sub-tropics, particularly to those areas not adapted to
natural dry periods. In order to study the vulnerability of cacao
(Theobroma cacao) – Gliricidia sepium agroforestry
plantations to droughts a large scale throughfall
displacement roof was built in Central Sulawesi, Indonesia. In this 19-month
experiment, we compared soil surface CO2 efflux (soil respiration) from
three roof plots with three adjacent control plots. Soil respiration rates
peaked at intermediate soil moisture conditions and decreased under
increasingly dry conditions (drought induced), or increasingly wet
conditions (as evidenced in control plots). The roof plots exhibited a
slight decrease in soil respiration compared to the control plots (average
13% decrease). The strength of the drought effect was spatially variable
– while some measurement chamber sites reacted strongly (responsive) to the
decrease in soil water content (up to R2=0.70) (n=11), others did
not react at all (non-responsive) (n=7). A significant correlation was
measured between responsive soil respiration chamber sites and sap flux
density ratios of cacao (R=0.61) and Gliricidia (R=0.65). Leaf litter CO2
respiration decreased as conditions became drier. The litter layer
contributed approximately 3–4% of the total CO2 efflux during
dry periods and up to 40% during wet periods. Within days of roof
opening soil CO2 efflux rose to control plot levels. Thereafter,
CO2 efflux remained comparable between roof and control plots. The
cumulative effect on soil CO2 emissions over the duration of the
experiment was not significantly different: the control plots respired
11.1±0.5 Mg C ha−1 yr−1, while roof plots respired
10.5±0.5 Mg C ha−1 yr−1. The relatively mild decrease
measured in soil CO2 efflux indicates that this agroforestry ecosystem
is capable of mitigating droughts with only minor stress symptoms. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|