Sodicity is a major issue affecting irrigated agriculture worldwide. Approximately 10% of the global land surface (13.2 billion hectares) is salt-affected due to long-term accumulation of dissolved salts in arid and semi-arid regions. These conditions damage soil structure, reduce fertility, and lead to significant agricultural losses.
Challenges in Sodic Soil Reclamation
Traditional methods of sodic soil reclamation involve costly amendments, water management, and drainage infrastructure. However, an alternative approach is to cultivate salt-tolerant crops that can grow and produce an economic yield under high sodicity.
Medicinal and Aromatic Plants for Sodic Soil Reclamation
Several medicinal and aromatic plants not only survive in sodic soils but also help in soil restoration while providing economic benefits. These crops can enhance rural employment opportunities and contribute to foreign exchange earnings.
Examples of beneficial plants:
- Palmarosa (Cymbopogon martini)
- Lemon grass (Cymbopogon flexuosus)
- Vetiver grass (Vetiveria zizanoides)
- Isabgol (Plantago ovata)
- Marigold (Tagetes sp.)
- Artemisia annua
- Senna (Cassia angustifolia)
- Periwinkle (Catharanthus sp.)
- Tulsi (Ocimum sp.)
These plants help reduce soil sodicity and improve physico-chemical properties through their root activities and organic matter contributions.
Enhancing Crop Productivity
The yield and quality of medicinal and aromatic plants can be further improved by applying:
- Organic amendments: Farmyard manure (FYM) and spent wash.
- Inorganic amendments: Gypsum, iron pyrite, and phosphogypsum.
However, the effect of sodicity on the biosynthesis of secondary metabolites (which determine medicinal plant quality) needs further research.
Vetiver Grass: A Natural Solution for Sodic Soil Reclamation
Vetiver grass (Vetiveria zizanioides), native to South and Southeast Asia, has been traditionally used to mark field boundaries. Today, it is widely recognized as the best natural solution for soil conservation due to its low cost, adaptability, and effectiveness.
Key Benefits of Vetiver Grass
- Prevents soil erosion and conserves moisture on rainfed lands.
- Low maintenance and cost-effective for small farmers.
- Resistant to burning, slashing, and moderate tractor traffic.
- Tolerant to pests, diseases, and nematodes.
- Thrives in open areas (but highly sensitive to shade).
Best Planting Practices for Vetiver Grass
- Planted along contours to control erosion.
- Slips should be planted at 20 cm spacing at the start of the rainy season.
- A vertical interval of 2 meters between hedges is usually sufficient.
- Takes 1 to 4 years to form a dense protective barrier.
Applications of Vetiver Grass
- Gully stabilization
- Waterway and drainage stabilization
- Soil erosion control
- Improving water quality by filtering sediment
- Flood damage reduction
- Land rehabilitation (quarries, mine spoils, acid sulfate soils, and contaminated sites)
Conclusion
Vetiver grass and other medicinal/aromatic plants offer a sustainable, eco-friendly, and cost-effective solution for reclaiming sodic soils. These plants not only restore soil health but also support rural economies by generating employment and income.
Dr. N. Satheeshkumar, Dr. P. Thukkaiyannan, Dr. R. Jeya Srinivas, Dr. R. Shri Rangasamy.
