For Farmers

Factors Affecting Nutrient Release:

1. Magma Composition – Different types of magma (basaltic, andesitic, rhyolitic) contain different mineral compositions, leading to variations in phosphorus, calcium, and other nutrients.
2. Tectonic Setting – Volcanoes at subduction zones (e.g., the Pacific Ring of Fire) tend to have different mineral contents compared to those at mid-ocean ridges or hotspots (e.g., Hawaii).
3. Eruption Style – Explosive eruptions (e.g., Mount St. Helens) produce fine ash with a high surface area for nutrient deposition, while effusive eruptions (e.g., Kilauea) release lava that weathers more slowly.
4. Local Geology – The pre-existing rock formations influence the final mineral content of the volcanic material.
5. Gas Emissions – Volcanoes also release gases like sulfur dioxide and carbon dioxide, which influence soil pH and nutrient availability.

Nutrient Variability from Past Data:

1. Phosphorus (P) – Found in volcanic ash but varies widely; basaltic eruptions generally release more phosphorus than rhyolitic eruptions.
2. Calcium (Ca) – Typically abundant in volcanic materials, especially in basaltic eruptions.
3. Nitrogen (N) – Not directly emitted in large quantities, but volcanic activity indirectly enhances nitrogen fixation by promoting microbial activity and atmospheric deposition.

Case Studies:

1. Icelandic Eruptions (e.g., Eyjafjallajökull, 2010) – Released moderate phosphorus and calcium, with long-term effects on soil fertility.
2. Krakatoa (1883) & Tambora (1815) – Enriched surrounding soils but varied based on eruption intensity and local geology.
3. Hawaiian Volcanoes (e.g., Mauna Loa, Kilauea) – Basaltic lava flows contribute high calcium and phosphorus levels but little nitrogen.