Integrating Pterocarpus indicus (Narra) into Your Agroforestry System
Narra is an excellent nitrogen-fixing tree that enhances soil fertility and supports high-value crops like Aquilaria malaccensis (Agarwood). Below are key strategies for maximizing its benefits in your agroforestry plantation:
1. Ideal Planting Arrangement
To optimize nitrogen fixation and provide shade without excessive competition, follow these planting layouts:
✅ Alley Cropping (Row Planting):
- Plant Narra in rows 5-7 meters apart with Agarwood, Sandalwood, or Nutmeg in between.
- Ensures nitrogen enrichment and shade regulation.
✅ Scattered Planting (Canopy Integration):
- Space individual Narra trees 10-12 meters apart within mixed plantations.
- Reduces competition for sunlight and maximizes root-zone nitrogen sharing.
✅ Windbreak or Boundary Planting:
- Plant Narra along farm borders (3-4 meters apart) to serve as windbreaks and soil stabilizers.
- Ideal for protecting essential oil crops from strong winds and soil erosion.
2. Soil Enrichment & Nitrogen Fixation
Narra enriches the soil by shedding nutrient-rich leaf litter, which decomposes and releases nitrogen. To maximize soil fertility:
Mulching: Use fallen Narra leaves around tree bases for natural fertilization.
Mycorrhizal & Bacterial Enhancement: Apply biofertilizers containing Rhizobia or Frankia bacteria to boost nitrogen fixation.
Companion Cropping: Combine Narra with leguminous cover crops (e.g., Arachis pintoi or Desmodium spp.) to further enrich the soil.
3. Pruning & Shade Management
To prevent excessive shading and competition:
Light Pruning (Every 6-12 months): Maintain an open canopy to allow sufficient sunlight for intercropped species.
Coppicing (Selective Cutting): If Narra grows too dense, cut back some branches and use them as organic mulch.
4. Additional Benefits of Pterocarpus indicus
✅ High-Value Timber: Narra is prized for durable, termite-resistant wood used in furniture and construction.
✅ Medicinal Properties: Bark and leaves have anti-inflammatory, antimicrobial, and wound-healing properties.
✅ Erosion Control: Deep root systems help prevent soil degradation in sloped plantations.
✅ Bee Forage & Biodiversity: Flowers attract pollinators, improving productivity in fruit-bearing crops like Nutmeg and Citrus.