Vegetable-agroforestry (VAF) system: Understanding vegetable-tree interaction is a key to successful farming enterprise
Intercropping vegetable under tree-based system is becoming popular practice in the uplands. Little information is available on the potentials of different vegetables species under tree-based systems. We hypothesised that in an intensive commercial vegetable production system in the uplands, monoculture system is not sustainable but integrating trees is feasible and offers better prospects. Our overall objective is to-integrate trees on intensive vegetable farming system with minimal negative interaction, thus increasing productivity, profitability, nutrient use efficiency and environmental services. An assessment of VAF systems was conducted in Lantapan, Bukidnon, Philippines, covering 21 farms, two agroforestry systems, six tree species, eight vegetables and four aspects. Data collected were tree parameters, spatial performance of vegetables, and spatial light transmission. Focus group discussion was also conducted with VAF farmers on ways of integrating trees on vegetable farms. Furthermore, a field experiment was established to evaluate 30 different indigenous and commercial, tree, fruit, leafy, root and climbing vegetables perpendicular to a six-year old Eucalyptus torillana hedgerows. Crop growth and yield data were collected spatially relative to tree distance in order to determine productivity, adaptability, competition, and complementarity indices. Net complementarity index (NCI) was used as a tool for assessing appropriate tree-vegetable integration. Adaptability indices of different types of vegetables to varying degree of light transmission as influenced by the tree hedge were also determined. Degree of competition (CD), supplementarity (SD), net supplementarity index (NSI), average relative yield (ARY) and percent yield increase or decrease (PY) due to the presence of trees in the intensive vegetables system were determine using the data generated from the experiment. Drip irrigation and tree root pruning were looked at their effect on Bell pepper productivity and VAF net complementarity. Elite lines of tomato which are resistant to tomato leaf curl virus (ToLCV), Bacterial wilt and Fusarium wilt were also evaluated under tree based systems in Lantapan, Bukidnon and Claveria, Misamis Oriental, Philippines.