Abstract
Agroforestry experiments usually include control plots of either pure crop or pure tree stands. A clear distinction should be made between intensively managed biophysical controls and farming system controls with realistic labour input and management regimes. Trying to draw biophysical conclusions from farming system controls (or the reverse) is often not justifiable. The design and management of these elusive control plots is a complicated issue which is often overlooked. Many factors beyond the control of the experiment manager can disturb long term field agroforestry experiments. Some examples from French agroforestry experiments illustrate how uncontrolled factors may bias the results, including the proportion of harvested to planted trees, the weeding regimes, and the use of tree-shelters. The analysis of agroforestry data could be more efficient when considering a continuum of tree — crop mixture management options between the agroforestry plot and the non agroforestry plot. The concept of biophysical control plots becomes then less essential. A relevant modelling approach of interactions between trees and crops should 1) perform correctly for any tree/crop proportion and even for pure stands, when setting the parameters of the other component to zero, 2) provide for the inclusion of new, uncontrolled factors that could emerge through time. The biological efficiency of agroforestry systems may however be a subordinate criterion for agroforestry adoption, as observed at the moment in France. Agroforestry systems with poor biological outcomes can even be very attractive in some ecological or sociological conditions, and only farming system controls may bring this aspect to light.
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References
Bagnall-Oakeley H, Conroy C, Faiz A, Gunawan A, Gouyon A, Penot E, Liangsutthissagon S, Nguyen HD and Anwar C (1997) Imperata management strategies used in smallholder rubber-based farming systems. Agroforestry Systems 36: 83–104
Balandier P and Dupraz C (1999) The growth of widely spaced forest trees. A case study from recent temperate agroforestry plantations in France. Agroforestry Systems 43: 151–167
Bergez JE and Msika B (1996) A silvopastoral model for the EU. In: Etienne M (ed) Bergez JE and Msika B, pp 207–220. INRA Editions
Bergez JE, Balandier P and Etienne M (1997) Sensitivity analysis of the ALWAYS silvopastoral simulation model across contrasting pedoclimatic conditions. In: Proceedings of the Montpellier International Conference on Agroforestry for Sustainable Land-use, June 1997, pp 395–399. Inra-Cirad editors, Montpellier, France
Cannell MGR, Van Noordwijk M and Ong CK (1996) The central agroforestry hypothesis: the trees must acquire resources that the crop would not otherwise acquire. Agroforestry Systems 34: 27–31
Dupraz C (1994) Prospects for easing land tenure conflicts with agroforestry in Mediterranean France: a research approach for intercropped timber orchards. Agroforestry Systems 25: 181–192
Dupraz C and Lagacherie M (1990) Culture de feuillus à bois précieux en vergers pâturés sur des terres agricoles du Languedoc-Roussillon: le réseau expérimental APPEL. Forêt Méditerranéenne 12 (4): 447–457
Dupraz C, Dauzat M, Girardin N and Olivier A (1995) Root extension of young wide-spaced wild cherry trees in an agroforest as deduced from the water budget. In: Ehrenreich JH, Ehrenreich DL and Lee HW (eds) Growing a sustainable Future, pp 46–50. Proceedings of the 4th North-American Agroforestry Conference, Boise, Idaho, USA
Dupraz C,Bergez JE and Balandier P (1997) Improved ventilated tree shelters as a key tool for innovative agroforestry practices in Europe. In: Proceedings of the Montpellier International Conference on Agroforestry for Sustainable Land-use, June 1997, pp 275–280. Inra-Cirad editors, Montpellier, France
Dupraz C and Newman SM (1997) Temperate Agroforestry: The European Way. In: Gordon A and Newman S (eds) Temperate Agroforestry Systems, pp 181–236. CAB International, Wallingford, Oxon, UK
Etienne M and Rapey H (1999) Simulating integration of agroforestry into livestock farmers’ projects in France. Agroforestry Systems 43: 257–272
Fernandes ECM, Davey CB and Nelson LA (1993) Alley cropping on an acid soil in the upper Amazon: mulch, fertiliser, and hedgerow root pruning effects. In: Technologies for sustainable agriculture in the tropics. ASA Special publication 56, pp 77–96. Madison, American Society of Agronomy
Fukai S and Trenbath BR (1993) Processes determining intercrop productivity and yields of component crops. Field Crops Research 34: 274–271
Haggar JP, Tanner EVJ, Beer JW and Kass DCL (1993) Nitrogen dynamics of tropical agroforestry and annual cropping systems. Soil Biol Biochem 25: 1363–1378
Hiebsch CK and McCollum RE (1987) Area x time equivalency ratio: a method for evaluating the productivity of intercrops. Agron J 79: 15–22
Huxley PA (1990) Experimental agroforestry. In: MacDicken KG and Vergara NT (eds) Agroforestry Classification and Management, pp 332–353. John Wiley and sons, New York, USA
Langton S (1990) Avoiding edge effects in agroforestry experiments; the use of neighbourbalanced designs and guard areas. Agroforestry Systems 12: 173–185
Mead R and Willey RW (1980) The concept of a `Land Equivalent Ratio’ and advantages in yields from intercropping. Expl Agric 16: 217–228
Ong CK (1996) A framework for quantifying the various effects of tree—crop interactions. In: Ong CK and Huxley P (eds) Tree—Crop Interactions: A Physiological Approach, pp 1–23. CAB International, Wallingford, UK
Ong C (1994) Alley farming: pies in the sky? Agroforestry Today 6 (3): 8–11
Price C (1995) Economic evaluation of financial and non-financial costs and benefits in agroforestry development and the value of sustainability. Agroforestry Systems 30: 75–86
Ranganathan R and de Wit CT (1996) Mixed cropping of annuals and woody perennials: an analytical approach to productivity and management. In: Ong CK and Huxley P (eds) Tree—Crop Interactions: A Physiological Approach, pp 25–50. CAB International, Wallingford, UK
Sanchez PA (1995) Science in agroforestry. Agroforestry Systems 30: 5–55
Schroth G and Zech W (1995) Root length dynamics in agroforestry with Gliricidia sepium as compared to sole cropping in the semi-deciduous rainforest zone of West Africa. Plant Soil 170: 297–306
Van Noordwijk M and Ong C (1996) Lateral resource flow and capture — the key to scaling up agroforestry results. Agroforestry Forum 7 (3): 29–31
Vandermeer J (1989) The Ecology of Intercopping. Cambridge University Press, 237 pp
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Dupraz, C. (1999). Adequate design of control treatments in long term agroforestry experiments with multiple objectives. In: Auclair, D., Dupraz, C. (eds) Agroforestry for Sustainable Land-Use Fundamental Research and Modelling with Emphasis on Temperate and Mediterranean Applications. Forestry Sciences, vol 60. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-0679-7_2
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DOI: https://doi.org/10.1007/978-94-017-0679-7_2
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