Stone Hill: Restoring Land for Sustainable Agriculture

A Rocky Beginning – The Origins of Stone Hill

Nestled near Nam Cat Tien National Park, Dong Nai, Stone Hill stands as a testament to perseverance and sustainability. Its original Vietnamese name, “Đồi Đá” (Stone Hill), was given by its founder, Teacher Phước, a respected Plant Physiology professor at Nong Lam University in Ho Chi Minh City.

I studied under him during my university years, and looking back, I realize that fate—or perhaps my natural inclination for agricultural science—led me here.

Back in 2010, Stone Hill was nothing more than a barren, rocky landscape spanning over 10 hectares. The soil was severely depleted from years of cassava farming, and water scarcity made cultivation nearly impossible. Yet, Teacher Phước embarked on an ambitious mission—to restore the land and turn it into a thriving cacao farm while ensuring long-term sustainable livelihoods for farmers.

However, the journey was far from easy.
 

The Challenge – Healing Depleted Soil & Water Scarcity

Before cacao could grow, two major obstacles had to be overcome:

1. Depleted Soil – Years of cassava farming had stripped the land of nutrients, leaving it uninhabitable for new crops.
2. Water Scarcity – Maintaining an entire farm with limited water sources posed a serious challenge.

In this article, I'll focus on the techniques Teacher Phước used to enrich the soil. In the next, I’ll dive into his water management strategies.

Compost & Soil Enrichment – Rebuilding the Earth

Early in my training, I studied two composting methods at Stone Hill:

• Compost Tea
• Compost Piles

These techniques weren’t new to me, but I had never fully implemented them due to the labor-intensive process of gathering materials and managing compost piles. Like many farmers, I took shortcuts—buying pre-composted manure or organic fertilizers from suppliers.

While this saved time, it came with several downsides:

✅ High costs – Store-bought fertilizers drain resources over time.
✅ Lack of control – Outsourcing compost means losing control over soil health.
✅ Uncertain quality – The consistency of purchased fertilizers varies.

Since my goal is sustainable farming, learning to create my own compost became essential. Even though I still source cow manure externally, making compost ensures better quality control and disease prevention.

Cold Composting Method – Slow but Effective

There are two primary composting methods:

• Hot Composting – A faster method that requires frequent maintenance.
• Cold Composting – Slower, but retains more nutrients in the soil.

At Stone Hill, I practiced the cold composting method due to its ability to preserve microbial diversity and improve soil health over time.
 

Step-by-Step Process:

1. Base Layer – Start with bamboo or wooden sticks to create airflow.
2. Organic Layers – Alternate between:
   • Slow-decomposing materials (straw, leaves).
   • Biochar (burned charcoal for potassium retention).
   • Fresh/dry manure (to introduce essential nutrients).
3. Moisture Control – Water each layer for steady decomposition.
4. Kitchen Waste – Add organic scraps to boost microbial activity.
5. Top Cover – Use soil or plastic sheets to preserve nitrogen and maintain humidity.
6. Temperature Monitoring – Insert a bamboo stick with a thermometer to track changes.

During the first 2-3 weeks, temperatures rise to 60-70°C, then gradually drop to 20-30°C, fostering fungi and beneficial microbes. Over time, this method will fully restore Stone Hill’s soil.

Compost Tea – A Microbial Powerhouse

Though rarely practiced due to its complexity, compost tea is one of the most powerful tools for soil restoration. At Stone Hill, I learned how to make it properly.

✅ Enhances soil fertility & microbial diversity
✅ Suppresses plant diseases naturally
✅ Cost-effective for small farms

Preparation Process:

1. Collect live earthworm compost (forest soil works best).
2. Prepare a water container (1:5 ratio for fertile soil, 1:10 for worm compost).
3. Add mashed ripe bananas or pure cane sugar (to feed microbes).
4. Aerate the mixture using an air pump for 24-48 hours.
5. Apply to soil for improved nutrient absorption and long-term regeneration.

With consistent use over 10 years, Stone Hill will transform into a forest again—a vision that reinforces the power of regenerative agriculture.

Biochar – Enhancing Soil Sustainability

While not part of my official training, Teacher Phước briefly touched on biochar’s benefits, and I made sure to take notes.

According to agricultural studies, one hectare requires 100 tons of biochar to maintain fertility and microbial balance. Farmers in the area use a simple method—digging pits and burning wood, skipping sophisticated designs.

Though this method isn’t perfect, biochar remains permanently in the soil, improving overall nutrient retention and soil structure.

Final Thoughts – Lessons from Stone Hill

During one of my training sessions, I asked Teacher Phước a simple yet profound question:
"What if I’m poor? What if I have no help?"

He answered:
"I have money, so I can buy truckloads of compost. If you’re poor, carry it by motorbike or by hand. It costs nothing. Poverty means you must work harder."

This struck a chord with me.
For farmers, making compost or compost tea can be a financial challenge. Large-scale farms may struggle with labor costs unless the owner personally manages the composting process.

At HuyEco Coffee Farm, I worry about rust fungi in compost piles, so I integrate hot and cold composting to maximize soil health.

Based on calculations, my farm requires:
✅ 34 tons of manure per hectare per year
✅ 100 tons of biochar for long-term soil improvement
✅ Compost tea for small-scale crops before applying it to coffee farms

Once my automatic irrigation system is fully operational, compost tea will be integrated, ensuring long-term sustainability at HuyEco Coffee Farm.