Effects of an experimental drought on the functioning of a cacao agroforestry system, Sulawesi, Indonesia

Authors

  • LUITGARD SCHWENDENMANN,

    1. Tropical Silviculture and Forest Ecology, Burckhardt Institute, Georg-August-University Göttingen, Büsgenweg 1, 37077 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • EDZO VELDKAMP,

    1. Soil Science of Tropical and Subtropical Ecosystems, Büsgen Institute, Georg-August-University Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • GERALD MOSER,

    1. Ecology and Ecosystem Research, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • DIRK HÖLSCHER,

    1. Tropical Silviculture and Forest Ecology, Burckhardt Institute, Georg-August-University Göttingen, Büsgenweg 1, 37077 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • MICHAEL KÖHLER,

    1. Tropical Silviculture and Forest Ecology, Burckhardt Institute, Georg-August-University Göttingen, Büsgenweg 1, 37077 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • YANN CLOUGH,

    1. Agroecology, Georg-August-University Göttingen, Waldweg 26, 37073 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • ISWANDI ANAS,

    1. Department of Soil Sciences and Land Resources, Faculty of Agriculture, Bogor Agricultural University (IPB), Jl. Meranti, IPB Darmaga Campus, Bogor 16680, Indonesia
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • GUNAWAN DJAJAKIRANA,

    1. Department of Soil Sciences and Land Resources, Faculty of Agriculture, Bogor Agricultural University (IPB), Jl. Meranti, IPB Darmaga Campus, Bogor 16680, Indonesia
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • STEFAN ERASMI,

    1. Cartography, GIS and Remote Sensing, Institute of Geography, Georg-August-University Göttingen, Goldschmidtstr. 5, 37077 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • DIETRICH HERTEL,

    1. Ecology and Ecosystem Research, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • DANIELA LEITNER,

    1. Landscape Ecology, Institute of Geography, Georg-August-University Göttingen, Goldschmidtstr. 5, 37077 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • CHRISTOPH LEUSCHNER,

    1. Ecology and Ecosystem Research, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • BEATE MICHALZIK,

    1. Landscape Ecology, Institute of Geography, Georg-August-University Göttingen, Goldschmidtstr. 5, 37077 Göttingen, Germany
    2. Institute of Geography, Friedrich-Schiller-University Jena, Löbdergraben 32, 07743 Jena, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • PAVEL PROPASTIN,

    1. Cartography, GIS and Remote Sensing, Institute of Geography, Georg-August-University Göttingen, Goldschmidtstr. 5, 37077 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • AIYEN TJOA,

    1. Faculty of Agriculture, Tadulako University, Palu 94118, Indonesia
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • TEJA TSCHARNTKE,

    1. Agroecology, Georg-August-University Göttingen, Waldweg 26, 37073 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.

  • OLIVER Van STRAATEN

    1. Soil Science of Tropical and Subtropical Ecosystems, Büsgen Institute, Georg-August-University Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
    Search for more papers by this author
    • 1L. S., E. V., D. H., I. A., G. D., S. E., D. He., C. L., B. M., A. T., and T. T. designed the experiment; L. S., G. M., M. K., Y. C., D. L., P. P., and O. v. S. performed the field work and laboratory analyses; L. S., E. V., G. M., D. H., M. K., and Y. C. analyzed and discussed the data; L. S. and E. V. wrote the paper. All authors commented on the manuscript.


Luitgard Schwendenmann, tel. +49 551 399 1118, fax +49 551 394 019, e-mail: lschwen@gwdg.de

Abstract

Agroforestry systems may play a critical role in reducing the vulnerability of farmers' livelihood to droughts as tree-based systems provide several mechanisms that can mitigate the impacts from extreme weather events. Here, we use a replicated throughfall reduction experiment to study the drought response of a cacao/Gliricidia stand over a 13-month period. Soil water content was successfully reduced down to a soil depth of at least 2.5 m. Contrary to our expectations we measured only relatively small nonsignificant changes in cacao (−11%) and Gliricidia (−12%) sap flux densities, cacao leaf litterfall (+8%), Gliricidia leaf litterfall (−2%), soil carbon dioxide efflux (−14%), and cacao yield (−10%) during roof closure. However, cacao bean yield in roof plots was substantially lower (−45%) compared with control plots during the main harvest following the period when soil water content was lowest. This indicates that cacao bean yield was more sensitive to drought than other ecosystem functions. We found evidence in this agroforest that there is complementary use of soil water resources through vertical partitioning of water uptake between cacao and Gliricidia. This, in combination with acclimation may have helped cacao trees to cope with the induced drought. Cacao agroforests may thus play an important role as a drought-tolerant land use in those (sub-) tropical regions where the frequency and severity of droughts is projected to increase.

Ancillary