Qualification Level: TESDA NC I – Sustainable Soil Management
Crop Focus: Agarwood (Aquilaria spp.)
Objective: Understand how nutrients move through the soil–plant system and how to manage them sustainably
I. INTRODUCTION
Nutrients in the soil are continuously recycled through physical, chemical, and biological processes.
Healthy nutrient cycling ensures sufficient supply for plant growth, reduces the need for chemical fertilizers, and supports long-term soil fertility.
Key Nutrients for Agarwood:
- Macronutrients: Nitrogen (N), Phosphorus (P), Potassium (K)
- Secondary nutrients: Calcium (Ca), Magnesium (Mg), Sulfur (S)
- Micronutrients: Iron (Fe), Zinc (Zn), Manganese (Mn), Boron (B)
II. NUTRIENT CYCLE IN SOIL
1. Nitrogen (N)
- Source: Organic matter, fertilizers, nitrogen-fixing microbes
- Transformations:
- Mineralization: Organic N → ammonium (NH₄⁺)
- Nitrification: NH₄⁺ → nitrate (NO₃⁻)
- Uptake: Roots absorb NH₄⁺ and NO₃⁻
- Losses: Leaching, volatilization, denitrification
- Role in Agarwood: Leaf growth, photosynthesis, resin precursor formation
2. Phosphorus (P)
- Source: Organic matter, phosphate fertilizers, phosphate-solubilizing microbes
- Transformations: Mineralization → phosphate ions (H₂PO₄⁻, HPO₄²⁻)
- Uptake: Absorbed as phosphate by roots (enhanced by mycorrhizal fungi)
- Role: Root development, energy transfer, flowering
3. Potassium (K)
- Source: Soil minerals, compost, organic fertilizers
- Function: Osmotic regulation, enzyme activation, water stress tolerance
- Uptake: Soluble K⁺ in soil solution
4. Micronutrients
- Iron, Zinc, Manganese, Boron, Copper
- Mostly present in trace amounts; availability depends on pH, organic matter, and microbial activity
III. SOIL–PLANT NUTRIENT DYNAMICS
- Organic Matter Decomposition
- Organic residues → microbes → mineralized nutrients → plant uptake
- Root Uptake
- Roots absorb nutrients via mass flow (water movement) and diffusion
- Mycorrhizal fungi and biofertilizers enhance uptake efficiency
- Nutrient Redistribution
- Nutrients move from old leaves to new growth
- Nutrient deficiencies often appear first in older leaves (mobile nutrients like N) or new leaves (immobile nutrients like Ca)
- Feedback to Soil
- Leaf litter, root exudates, pruned branches return nutrients to soil
- Supports microbial activity and continued nutrient cycling
IV. ROLE OF BIOFERTILIZERS
| Product | Function in Nutrient Cycling |
|---|---|
| Biogrow | N-fixers and P-solubilizers increase N and P availability |
| Mycoboost | Mycorrhizal fungi enhance P and micronutrient uptake |
| VitaSoil | Stimulates microbial activity → faster organic matter decomposition |
| EcoZyme | Enzymes accelerate nutrient mineralization from organic residues |
| BioKelp | Provides trace elements and plant hormones → improves nutrient use efficiency |
Key Principle: Healthy soil biology ensures nutrients are available when plants need them, while reducing losses due to leaching or volatilization.
V. FARMER-FRIENDLY NUTRIENT MANAGEMENT PRINCIPLES
- Maintain soil organic matter (3–5% minimum)
- Apply biofertilizers at proper doses and intervals
- Mulch and recycle plant residues
- Avoid over-application of chemical fertilizers (prevents nutrient imbalance)
- Monitor soil pH (5.5–6.8 for optimal nutrient availability)
- Consider plant stage:
- Early growth: focus on N and P
- Resin induction: moderate N, maintain P and K for stress tolerance
VI. INTEGRATED NUTRIENT CYCLE IN AGARWOOD SYSTEM
- Soil → Microbes → Roots → Tree → Resin Production
- Leaf litter and pruned branches return organic nutrients to soil
- Biofertilizers accelerate mineralization and nutrient availability
- Soil moisture management ensures efficient nutrient uptake
- Balanced nutrient cycling supports resin quality and tree survival
VII. TESDA NC I PERFORMANCE STANDARD
Learner must demonstrate ability to:
- Explain key nutrient cycles (N, P, K, micronutrients)
- Identify signs of nutrient deficiencies and excesses
- Apply biofertilizers and organic amendments to optimize nutrient cycling
- Monitor plant growth and soil health for nutrient efficiency
VIII. FARMER CHECKLIST
☐ Organic matter maintained
☐ Biofertilizers applied according to stage
☐ Mulch or plant residue returned to soil
☐ Soil pH suitable for nutrient availability
☐ Nutrient deficiencies identified and corrected
☐ Irrigation supports nutrient uptake
This module links soil biology, biofertilizer use, and nutrient cycling directly to Agarwood growth, health, and resin formation.