Tapping panel diagnosis, an innovative on-farm decision support system for rubber tree tapping

Latex is a key product for many tropical countries, of which 80% is produced by smallholders. Latex is produced by the rubber tree (Hevea brasiliensis). Given the 7-year immature unproductive period, establishing a rubber plantation requires considerable investment by smallholders, emphasizing the need for sustainable management. The difficulty of performing an agronomic diagnosis of a tree crop is to obtain an accurate picture of current and past cultivation practices, to be able to assess their impacts on the agro-ecosystem as well as on sustainability. Smallholders do not usually keep records of latex yield or of their technical practices, making it impossible to perform a diagnosis based on productivity. As latex harvesting involves tapping the bark, which leaves scars on the trunk, we hypothesised that these morphological traces would be good indicators of current and past practices and would thus enable a diagnosis based on the economic lifespan of plantation. To this end, we formalised a tapping panel diagnosis that involved reproducing the scars on tapping panel diagrams, and analysing them using two indicators: the amount of virgin bark consumed and the number of tapping years that remained. We validated this tapping panel diagnosis in a sample of 25 smallholder plantations in Cameroon, where we characterised eight tapping management systems reflecting different levels of tapping intensity. The assessment of the respective share of each tapping practice on virgin bark consumption revealed major effects of tapping frequency and of shaving thickness. We showed that the tapping panel diagnosis used as a decision support tool can increase remaining tapping years by 33% to 355%. To conclude, the tapping panel diagnosis formalised here for the first time will be a useful support for the participatory development of innovating tapping management schemes involving both technicians and smallholders.

[1]  P. Compagnon Le caoutchouc naturel : biologie, culture, production , 1986 .

[2]  É. Gohet,et al.  Long-term effect of ethylene stimulation on the yield of rubber trees is linked to latex cell biochemistry , 2010 .

[3]  O. Luukkanen,et al.  Gum arabic yield in differently managed Acacia senegal stands in western Sudan , 2005, Agroforestry Systems.

[4]  Sanford Weisberg,et al.  An R Companion to Applied Regression , 2010 .

[5]  Thierry Michels Adapter la conduite des plantations d'hévéa à la diversité des exploitations villageoises : étude de cas au Cameroun , 2005 .

[6]  Wei Xiaodi,et al.  Special communication: Revised International notation for latex harvest technology , 2009 .

[7]  M. Olsson,et al.  Gum and resin resources from some Acacia, Boswellia and Commiphora species and their economic contributions in Liban, south-east Ethiopia , 2004 .

[8]  R. Gras,et al.  Le fait technique en agronomie : activité agricole, concepts et méthodes d'étude , 1989 .

[9]  B. Chambon,et al.  Commercialisation du caoutchouc naturel des plantations villageoises : un facteur essentiel du développement de l'hévéaculture au Cameroun , 2009 .

[10]  S. Bellon,et al.  Is the plot concept an obstacle in agricultural sciences? A review focussing on fruit production , 2010 .

[11]  U. Ligges Review of An R and S-PLUS companion to applied regression by J. Fox, Sage Publications, Thousand Oaks, California 2002 , 2003 .

[12]  P. Thaler,et al.  Carbohydrate reserves as a competing sink: evidence from tapping rubber trees. , 2007, Tree physiology.

[13]  J. Meynard,et al.  Yield and protein concentration of spring malting barley: the effects of cropping systems in the Paris Basin (France) , 2003 .

[14]  Eric Navarro,et al.  Using on-field data to develop the EFI© information system to characterise agronomic productivity and labour efficiency in peach (Prunus persica L. Batsch) orchards in France , 2009 .

[15]  L. Coulibaly,et al.  Effect of tapping systems and height of tapping opening on clone PB 235 agronomic parameters and it's susceptibility to tapping panel dryness in south-east of Côte d'Ivoire , 2009 .

[16]  David Makowski,et al.  Methodological progress in on-farm regional agronomic diagnosis. A review , 2011, Agronomy for Sustainable Development.

[17]  D. Plénet,et al.  Relevance of orchard design issuing from growers' planting choices to study fruit tree cropping systems , 2003 .

[18]  Eric Scopel,et al.  Diagnosis of the productivity gap using a crop model. Methodology and case study of small-scale maize production in central Brazil , 2003 .

[19]  D. Roussel,et al.  Yield limiting factors, latex physiological parameters, latex diagnosis, and clonal typology , 1989 .

[20]  T. Doré,et al.  A diagnostic method for assessing regional variations in crop yield , 1997 .

[21]  David Makowski,et al.  Which decision support tools for the environmental management of nitrogen , 2002 .

[22]  É. Gohet,et al.  Panel management in rubber (Hevea brasiliensis) tapping and impact on yield, growth, and latex diagnosis , 2004 .

[23]  P. George,et al.  Natural rubber agromanagement and crop processing , 2000 .

[24]  André Fel R. Gras, M. Benoit, J.-P. Deffontaines, P.-L. Osty et alii, Le Fait technique en agronomie. Activité agricole, concepts et méthodes d'étude , 1990 .

[25]  Christine Aubry,et al.  DéciBlé, a software package for wheat crop management simulation , 2005 .

[26]  V. Souchère,et al.  Agronomy for sustainable agriculture. A review , 2011, Agronomy for Sustainable Development.