???? Introduction: What Are Nitrogen-Fixing Trees?
Nitrogen-fixing trees (NFTs) are special trees that can convert nitrogen gas from the air into a form that plants can use. This process is called nitrogen fixation, and it is done with the help of Rhizobia bacteria or actinomycetes in the tree’s root system.
✨ Benefits of Nitrogen-Fixing Trees in Plantations
| Benefit | Explanation |
|---|---|
| ???? Improves Soil Fertility | Adds nitrogen to the soil naturally, reducing the need for synthetic fertilizers |
| ???? Supports Tree Health | Strengthens surrounding crops or trees by sharing nutrients through roots |
| ???? Boosts Organic Matter | Leaf litter and biomass improve soil structure and moisture retention |
| ???? Enhances Biodiversity | Provides shelter and food for beneficial insects and animals |
| ???? Increases Yield | Healthier trees and better soil conditions support higher productivity |
???? Common Nitrogen-Fixing Trees in the Philippines
| Tree Species | Fixation Type | Notes |
|---|---|---|
| Gliricidia sepium | Rhizobial | Excellent hedgerow or shade tree; fast-growing |
| Leucaena leucocephala | Rhizobial | Good for fodder, alley cropping, and erosion control |
| Sesbania grandiflora | Rhizobial | Useful as windbreak and fast decomposer |
| Calliandra calothyrsus | Rhizobial | Provides nitrogen and high biomass for mulch |
| Pterocarpus indicus (Narra) | Rhizobial | Native NFT and national tree of the Philippines |
| Intsia bijuga (Ipil) | Rhizobial | Nitrogen-fixer and high-value timber tree |
| Moringa concanensis | Rhizobial | Reported to show signs of nitrogen fixation, good for agroforestry |
| Caesalpinia pulcherrima | Rhizobial (when inoculated) | Ornamental and potential nitrogen-fixer with Rhizobia inoculation |
???? What is Inoculation?
Inoculation means adding beneficial Rhizobia bacteria to the roots of nitrogen-fixing trees to ensure successful nitrogen fixation.
☑️ Benefits of Inoculating NFTs:
- Improves early growth
- Ensures nodule formation
- Increases nitrogen input to the soil
???? Tip: Inoculate tree seedlings in the nursery using commercial Rhizobia powders or slurries before field planting.
???? Planting NFTs in Agroforestry Systems
???? Suggested Spacing:
- Gliricidia/Leucaena: 1.5 to 2 meters apart
- Large NFTs (Narra/Ipil): 4 to 6 meters apart
???? Interplanting:
- Combine NFTs with main crops like Aquilaria (agarwood), coffee, cacao, or fruit trees
- Plant NFTs on borders or in alleys for maximum soil benefit
???? Visual Guide to NFT Benefits
✅ Nitrogen Fixation
✅ Soil Enrichment
✅ Mulching & Green Manure
✅ Support for Main Tree Crops
[Insert infographic with illustrations of root nodules, intercropping layout, and benefits]
???? Management & Maintenance
- Prune regularly to avoid shading of main crops
- Use pruned branches as mulch or compost
- Monitor for pests (especially in young seedlings)
- Replenish inoculants if trees are stunted
???? Tools & Supplies
- Inoculated seedlings or Rhizobia packs
- Trowel or spade
- Watering can
- Organic mulch
???? Sustainability Impact
NFTs help reduce reliance on chemical fertilizers, protect watersheds, and increase resilience of farming systems.
???? Field Application Tip:
Alternate every 2–3 rows of agarwood with a row of NFTs to maximize long-term soil fertility and tree health.
Let nature help your farm grow sustainably! ????