soil

Terra Preta is an increasingly prominent term in the world of permaculture. Leanan at The Oil Drum posted a link to a good article from Discover magazine the other day introducing the suspected origins, composition, and benefits of Terra Preta soils. The article serves as a great first look at the complex nature of soil science.

Terra Preta (“black earth”) refers to certain dark soils found in South America dating from 500 to 2500 years ago. What is so exciting about these soils is their amazing (and persistent) fertility, which far surpasses any of the surrounding soils. They are characterized by high levels of carbon (150 gC/kg soil), high levels of phosphorus (200 – 400 mgP/kg soil), and soil depths of 1 - 2 meters. Researchers believe the prime contributor to Terra Preta soils is bio-char (charcoal) with important contributions from clay pottery shards and composted organic material.

Continuing with the topic of soil management, this article on the importance of forest soil nutrition for carbon sequestration was intriguing. If you hope to help fight global warming by planting trees, make sure you pay attention to soil nutrition or you may end up doing very little to remove carbon dioxide. It’s also something to consider if you want a healthy source of timber after Peak Oil.

The Energy Bulletin had a fascinating post on modern soil science and management. There is so much we don't understand about how we grow our food, yet so few are willing to question the practices. It sounds eerily like Peak Oil and the way we use energy...

An excerpt:

"Magic" is how humans have customarily described the soil's natural cycles of decay and growth. Without a scientific understanding, our ancestors relied on observation and traditional practices to grow crops.