1. Tree – Vegetable Interaction in Vegetable Agroforestry Systems
Progress Report
Agustin R. Mercado, Jr
ICRAF .

2. TMPEGS
Technology:
Develop economically viable and ecologically-sound vegetable-agroforestry (VAF) systems

3. Overall hypothesis
In intensive vegetable production system in the uplands, monoculture systems are not sustainable, but integrating trees is feasible and offers better prospects.

4. Vegetable Agroforestry System (VAF) Research goal:
Tree-vegetable integration on farm with minimal negative interaction, thus increasing productivity, economic profitability, nutrient use efficiency and environmental services

5. VAF Research Issues AF systems Segregate Integrate Boundary planting
Parklands
Alleycropping or hedgerow intercropping
Tree species
Timber trees
Fruit trees
Canopy type: broad, medium, narrow
Vegetable types
Crucifers: Cabbages, Broccoli, Squash
Tubers: Potato,
Solanaceous: Tomato, eggplant,

6. Specific hypotheses
Vegetable based agroforestry (VAF) systems provide better productivity, increase fertilizer use efficiency (FUE), increase profitability and improve environmental services than vegetable monoculture system
Application of model allows a more rapid progress in on-farm trials and site-management designs
Integration (domestication) of indigenous tree vegetables offers additional option for sustained supply of vegetables for poor rural households.

7. Two research topics: VAF tree-soil-crop interaction
Domestication of indigenous tree vegetables

8. General objectives
To understand the nature of vegetable-soil-tree interactions in different types of tree integration on vegetable systems as the determinant for agro- silvocultural management options for enhancing the productivity of all components ( tree, vegetable, etc).
To examine service functions provided by VAF systems such as nutrient safety-net and nutrient pump functions, carbon stocks (above-and belowground) and build up of soil organic matter (SOM)

9. Specific objectives
To determine existing VAF systems and understand its potential and constraints
To evaluate existing VAF systems on light capture and tree growth and spatial vegetable productivity in relation to tree distance.
To improve VAF systems by understanding vegetable –soil – tree interaction and employing appropriate agro-silvocultural practices in order to attain optimum productivity of all components.
To test the hypothesis that tree roots act as safety-net for leached nutrients in intensive vegetable production system
To collect and evaluate indigenous tree vegetables under farmers management

10. Ongoing and planned research activities
Vegetable farming system diagnosis (VFSD)
Assessment of existing vegetable based agroforestry systems.
VAF system improvement.
Optimum light transmission as basis for silvicultural management (spacing, thinning, pruning, etc).
Vegetable and tree growth and productivity.
Tree-vegetable matching

11. Testing the hypothesis that tree roots act as safety-nets
Testing the hypothesis that tree roots act as safety-nets. Increased fertilizer use efficiency and reduction of fertilizer leaching (particularly on nitrate) thus avoiding contamination to water sources. (If 15N enriched fertilizer is available).
Testing the hypothesis that trees act as nutrient pump. Use of depth placement of 15N method. (If 15N isotope enriched fertilizer is available).
Quantification of environmental services (C sequestration – contribution of trees to soil organic matter build up (use of 13C method) and aboveground C stocks. Develop tree growth and allometric models)

12. Deliverables
Recommendation for vegetable- tree combination and management with minimal negative interaction
Improved options for tree spacing and vegetable-tree intercrop patterns
Profitable vegetable-tree systems identified

14. Net benefit= T+ (2y2-2y1)-D

16. D

17. Activities conducted so far:
Assessment of existing VAF systems covering 21 farms, 2 AF systems, 6 tree species, 8 vegetables, 4 aspects. Data collected were tree parameters (stem diameter, tree height, canopy height and width), spatial performance of vegetables (height, stem diameter, crown width, biomass), spatial light transmission (fish eye photography/quantum light meter)
Focus group discussion with 15 VAF farmers on various ways of integrating trees on vegetable farms and their practices and experiences on tree and vegetable managements addressing tree-vegetable competition and complementarity.
Nursery establishment and management of indigenous tree vegetables and medicinal trees. ,

18. Eucalyptus robusta + tomato at Gunayan’s farm at Bul-ogan, Sungco, Lantapan.

19. Eucalyptus- tomato interaction under boundary planting system

20. Three zones of tree-crop interaction in vegetable agroforestry systems

21. \ Effect was due to: Light competition (aboveground)
Nutrient competition
Effects were due to:
Aboveround (light competition)
Belowground (water, nutrients, etc)

22. Proportion of total light transmitted spatially using fish-eye photography analyzed with gap light analyzer software. Farmer removed approximately 40% of the canopy

23. Net complementarity as a simple tool in assessing appropriate tree-vegetable integration
Net complementarity = degree of complementarity-degree of competitiveness
Degree of complementarity = relative yield (at complementarity zone) – 1 x distance of influence
Degree of competitiveness = 1- relative yield (at competition zone) x distance of influence
Relative yield at complementarity zone = yield at complementarity zone/neutral zone
Relative yield at competition zone = yield at competition zone/neutral zone

24. Three zones of tree-vegetable interaction in vegetable agroforestry systems

25. Influence of timber tree species on net complementarity
Acacia mangium
Eucalyptus robusta
Eucalyptus torillana
Gmelina arborea
Maesopsis emini
0.23
0.48
0.30
0.85
1.67 1 7 3 8

26. Influence of vegetable crops on net complementarity
Vegetables
Net complementarity n
Bell pepper
Brocolli
Cabbage
Cauliflower
Chinese cabbage
Tomato
White beans
Maize
0.14
-7.54
0.98
0.44
0.57
-0.48
-1.67
-1.55 3 1 2 7 4

27. Influence of aspects on net complementarity
East (vegetables on west side)
West (vegetable on east side)
North (vegetable on south side)
South (vegetable on north side)
1.74
-1.06
0.54
2.09 7 4 3

32. Domestication of indigenous tree vegetables
Objectives:
- Collect and propagate indigenous tree vegetables
- Household food and nutritional security (available 365 days a year)
- Environment friendly (no pesticides, better carbon sequestration)
- Seed banking (in situ)
- Reduced production risks
Indigenous tree vegetable species:
Gnetum gnemon – “Bago”
Abelmuchos manihot – “Lagikway”
Sesbania sesban – “ Katuray”
Moringa oliefera – “Malunggay”
Looking for more entries
Evaluation activities:
- Propagation methods (clonal propagation and nursery establishment at Claveria)
- As contour hedgerows
- As live fences

33. Evaluation activities:
Medicinal trees
Cinnamomum mindanensi (Kalingag)
Cinchona pubescens (Kenina)
Camella sinensis (Tea)
Cinnamomum verum (Cinnamon)
Vitex negundo (Lagundi)
Evaluation activities:
- Clonal propagation methods
- As hedgerows (farmers –managed) as SPA
- As live fence (farmers –managed) as SPA
Progress so far
Clonal chamber has been established
Potted seedlings of 1000 pcs for each of the species have been raised
Collection of more entries

34. Summary and initial findings
1. Integration of trees on farm is only feasible if :
Complementarity is greater than competition (Net complementarity is > 0). Net complementarity can be a simple tool for assessing appropriate tree-vegetable integration.
The cumulative value of tree products is greater than the cumulative values of yield loss and crop displacement area (cropped area loss).
2. Optimum tree spacing or tree line (hedge spacing) in AF system can be achieved when two complementarity zones meet. Approximately meters apart.
3. Eucalyptus robusta, Eucalyptus torillana and Acacia mangium are promising trees for VAF system
4. Cabbage, Chinese cabbage, cualiflower and bell pepper are suitable vegetables for VAF

35. Thank you very much indeed for listening!!