Sustainable Management of Fruit Orchards in the Soconusco, Chiapas, Mexico - Intercropping Cash and Trap Crops

for the financial support for the work und their generous trust. Miss Buechl provided additional administrative support and moral support during the studies in Germany. Esta obra de esfuerzo y trabajo conjunto esta dedicada a mi querida familia. SUMMARY South Mexico belongs to the Mesoamerican tropical region. The typical production systems are characterized on the one side by high diversity home gardens and by export orientated plantations like mangoes, avocados, papayas, and minor fruit crops. On the other side, subsistence agriculture remains the rule for the production of basic food crops like maize and beans, through traditional management systems. Both production systems integrate practices based on intensive use of agrochemicals, which eventually affect the natural resources in the medium and long term. The alarming agro-ecological conditions of the tropical fruit systems have awakened our interest to conduce field experiments during 2005-2007 in the Soconusco Region. Special attention has been given to the different effects of intercropped annual crops within the fruit plantations on the dynamics and structure of the weed and insect populations as well as on the chemical and biological parameters of soil fertility. Moreover, growth and yield parameters of the selected fruit crops, mango and rambutan and of the integrated annual intercrops were evaluated. The investigations have been carried out in two typical fruit orchards in the Soconusco, the humid tropical region of Mexico. The experiments are located in a mango orchard at 14 x 14 m in Cintalapa (15º 19' 431" N, 92° 37' 369" W, altitude 184 m.a.s.l) and in a rambutan plantation at 8 x 8 m in El Triunfo (15º 21' 147" N, 92º 33' 176" W, altitude 335 m.a.s.l). Each experimental orchard with a total area of 9408m² includes eight intercropping scenarios, arranged in four major crop rotations together with a control plot of mango/rambutan without annual intercrops. Since May 2005, the traditional maize-straw fallow rotation and the improved maize + pumpkin-straw fallow crop rotation have been compared in cycles 1-2 and 3-4 together with the same rotations to which a leguminous intercrop had been added in the fallow cycles 2 and 4. The maize crop lasted from May to August and the legumes intercrop within the fallow cycle from august to march. For each legume crop rotation, three leguminous scenarios were implemented: Crotalaria spectabilis and Vigna unguiculata in both orchards, Crotalaria longirostrata in Rambutan and Phaseolus acutifolius in Mango only. In each …