It’s easy to think all soil is the same. After all, dirt is dirt, right? 

Not really. Pedology, or the study of soils, is a vast and complex field, and the differences in soil types and qualities are well documented. 

In soil science, it’s widely accepted that volcanic soils are some of the most fertile, nutrient-dense, and desirable soils in the world. For farmers, volcanic soils mean higher harvests, stronger plant health, and longer production cycles. 

Let’s take a look at why volcanic soils are so highly sought after by farmers. 

Stronger Nutritional Profile

The high fertility of volcanic soil is due to the chemical composition of the volcanic matter (lava, ash, etc.) produced by eruptions. While the exact composition will vary from site to site, volcanic soils are notably high in:  

• Iron
• Calcium
• Magnesium
• Sodium
• Potassium
• Phosphorous
• Sulfur
• Silicon
• Many trace elements

Volcanic soil is also known for its dark color, excellent structure and consistency (especially in clay conditions), low bulk density, and ability to hold large amounts of moisture. 

The quality of volcanic soil is further enhanced by the lush foliage that thrives in it. Coupled with ample rainfall in the mountain elevations, the decomposition of the vegetation creates large amounts of organic matter which adds more nutrients and enhances the soil tilth.

Lava and ash are both components of volcanic rock and each has different effects on the soil. 

Lava and Volcanic Soil

Some eruptions cause an expulsion of molten lava, which spews out or flows down the side of the volcano. As the lava cools and hardens, it creates a lava field. Over the course of hundreds or even thousands of years, this lava field breaks down, adding nutrients and porosity to the soil.

How quickly the lava takes to break down depends on several environmental factors, especially rainfall. This is one aspect of chemical weathering, which is the process where rocks are broken down and their released minerals become accessible to plants and animals. An important aspect of the breakdown of this volcanic bedrock is the increased porosity of the resulting soil. Porosity affects everything from nutrient absorption to water retention to root health, making it key for soil quality. 

Ash and Volcanic Soil

Volcanic eruptions also cover the surrounding earth in ash and other particles. Volcanic soils composed primarily of volcanic ash are called Andisol, and while they only cover less than 1% of the entire earth’s land area, Andisols account for roughly 60% of all the soil in tropical countries. 

Even immediately following an eruption, research has shown that crops support significantly higher yields even when buried under 20cm (8 inches) of ash. The ash then breaks down very quickly and is easily incorporated into the soil where its benefits are readily available to plants.

On top of adding the nutrients mentioned above, volcanic ash also:

• Improving soil water-retention capabilities by lowering permeability.
• Reflecting 40-60% more solar radiation and increasing photosynthesis. 
• Holding nutrients and preventing leaching. 
• Reducing evaporation,
• Keeping the soil 6-10C cooler during the heat of the day.
• Aiding the accumulation of humus in the soil

Growing In Volcanic Soil

The texture of volcanic soil is typically sandy loam with a friable consistency (which is neither plastic nor sticky). It also has good porosity and excellent aeration and drainage. In short, it is an ideal soil type for many crops and plants. 

Each soil type has its own unique characteristics. Factors that affect the growing conditions in volcanic soils include loose soil that is prone to erosion, delayed pollination or germination in areas of more recent volcanic activity, acidic soil pH, and highly moist soils.

To protect these delicate and easily eroded soils, responsible farming methods are essential, including:

1. Careful excavation and tilling
2. Growing crops that prefer acidic soil
3. Making use of water retention to grow moisture-loving crops (which is especially beneficial to fruit trees)
4. Timing germination and flowering to favorable conditions 

Volcanic Soil in Colombia

The presence of volcanic soil is a huge advantage for Colombia in terms of its farmland quality. Colombia is located in the Ring of Fire, a 40,000km volcanic territory largely on the coast of the Pacific Ocean. 

The Andes mountains that bisect Colombia formed over the last 20,000 years from ancient volcanoes. Roughly 12% of the national territory is covered with ash soils, and Colombian farms sit atop the pyroclastic materials from ancient eruptions. 

Colombia has another advantage with its high annual precipitation, and the rain and flowing rivers have slowly worked away at the volcanic soil. Some of the river valleys in the country, such as the Sinú, Magdalena, and Orinoco, are among the most fertile in the world. While coffee is a large part of Colombia’s agriculture, many crops can thrive in the circumstances, 

Conclusion

For centuries, farmers have sought out volcanic soils, and for good reason. The nutrient profile and absorption qualities are entirely unique, and combined with the right climate conditions can be an enormous advantage for farmland assets. 

The presence of volcanic soils is a major reason why Farmfolio chose Colombia for its first round of farmland ownership opportunities. To learn how you can gain exposure to these incredible assets, get in touch with our team. 

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