Steward – November 2018

The Biochar Story

Coordinator’s Corner: Six-legged fall invaders

The Biochar Story

by Tim Overdier
Northport, MI

Figure 1: Biochar (National Geographic)

Biochar is a natural high-carbon soil builder. As the name implies, “bio” represents a biological coating on a “char” particle produced in a low oxygen burn (pyrolysis). Biochar (Fig. 1) is much like charcoal but rather than purposed for fuel, it is created for use as an agricultural soil amendment. Biochar’s unique electrochemical properties and high surface area (Fig. 2) adsorbs nutrients and greenhouse gases, increases nutrient and water holding capacities, and provides habitat for a diversity of beneficial soil microbes. Biochar can be processed from many types of organic wastes.

While the name “biochar” was only coined in 2005, this material was used by Amazonian Indians as far back as 2500 years ago.

Figure 2: A microscopic view of biochar (

A Spanish expedition In 1542 a Spanish expedition seeking gold and cinnamon put into the headwaters of the Amazon with a young Conquistador named Francisco de Orellana. On the way to the Pacific ocean, Orellana’s scribe, Friar Gaspar de Carvajal, recorded that the party encountered extensive and grand villages with ornate plazas, lush green fields, roads, and warehouses of stored exotic foods, corrals of turtles and manatees, ferocious warrior women, and tall warrior men painted black.


So remote was the Amazon, that by the time researchers of the late 19th century returned to the area there were no such villages. Carvajal’s writings were considered to be myth. Modern studies indicate that European-introduced diseases decimated the ancient civilizations by about 95 percent.

Since then geologists and archaeologists passed through the area in the 19th and 20th Centuries, found buried beneath the Amazon rain forest a soil called “Terra Preta” — Portuguese for “dark earth”. In 1874 a geology report by a Dr. Charles Hartt of Cornell described the terra preta soils as a “kitchen middens, created by 1000 kitchens over 1000 years”, indicating a loop of carbon recycling that returned refuse – cooking char, pottery shards, and bones– back into the soil to grow crops. Everything but the kitchen sink…

It wasn’t until after the advent of “soil science” in the 20th Century that more specific chemical and physical properties of terra preta were analyzed. In 1996, William Sombroek, a soil scientist from the Netherlands completed the first PhD thesis on terra preta, offering to the world the classic side by side photo of soil profiles (Figure 3.) with the dark, Anthropogenic or human-made terra preta next to the native tropical soil. The key ingredient Sombroek identified was the char, along with a host of diverse microbes that comprised the fertile, well-structured soil.

By contrast, the native tropical soils are highly weathered red clays, acidic, and lacking in organic matter and nutrients. The dark earth profile at over 15% organic matter enabled the cultivation of food crops that would not have been possible in the native soils. So while these civilizations that supported millions of Amazonian people disappeared, they may have left behind a soil solution to the carbon balance we now need for a sustainable future.

Northwest Michigan’s upland topsoils cleared for agriculture are typically 1-2 percent organic matter. They could easily become 3 to 5 percent with changes in management, including the addition of biochar.

Today, a high tech 21st Century worldwide biochar effort to improve the pyrolysis procedures, environmental monitoring, process engineering, marketing, and economics is underway. Education and public awareness remain a big factor for successful implementation of a future with appropriate biochar applications. Nearly 125 institutions worldwide are studying biochar, including 15 colleges and universities in the United States.

Figure 3: Native tropical soil on the left; terra preta on the right. (Dr. Wm Sombroek)

The International Biochar Initiative has successfully advocated for the inclusion of biochar into the proposed United Nations Framework Convention on Climate Change, and at least 20 countries have supported the inclusion of biochar as a high-potential climate change mitigation and adaptation tool.


In 2018, Cool Terra, a U.S. company financed by Google, Exxon Mobil, JR Simplot, USDA, and others, are rolling out a high carbon, microbially inoculated, enhanced biochar. This product is the result of several years of filing 35 patents, field trials though Colorado State University and a California research firm. The granular product will provide farms, orchards, turf growers, and greenhouses with an incremental, high return soil amendment, that will help shift farms from the chemical treadmill to a more ecologically sustainable, set of soil building practices. This is just the beginning of biochar moving into the mainstream.

Other uses of biochar such as wastewater treatment, electrical cells, and hazardous material cleanup are being researched.

With our NW Michigan excess woody debris, a small fire, and a water source to douse the flames before the fire burns to ash, we can make biochar and make a difference in the carbon cycle and our local food. Figures 4 and 5 show results in my Northport garden in 2017 with biochar additions to 30 inches of depth.

There will be a two hour Biochar Workshop at Grow Benzie November 3, 2018 to introduce the process for NW Michigan gardeners and growers.

Biochar: be the change!

Figure 4: early leaf out on tomato
transplants in biochar treated soil in
Northport. (Started indoors and given to
me by a Master Gardener here!)

Figure 5 Tomato crop sampling,
spotless mixed varieties.








Coordinator’s Corner: Six-legged fall invaders

Nate Walton, MSU Extension Master Gardener Coordinator

As the shadows lengthen and days get shorter, we start to see some six-legged friends sneaking around our windows, eaves, and soffits. This seems like a good time for a reminder about just who some of these insects are, and how you can tell them apart.

The fall invaders are all just following their natural inclination to seek an out of the way resting place to spend the winter. Unfortunately for all parties involved, what happens next is anything but natural.

The exterior side walls of our structures provide a very attractive array of nooks and crannies for these critters. The problem is that these nooks and crannies often lead into the interiors of our human dwellings. Three of the most common insects that we find doing this in Michigan are Brown Marmorated Stink Bug, Box Elder Bug, and Western Conifer Seed Bug, and are all closely related insects in the insect order Hemiptera (true bugs).

Of these three, the newest to our area and most problematic by far is the Brown Marmorated Stink Bug (BMSB). A great deal of information on identification and management of BMSB can be found on the website

Keeping all three of these insects out of our structures can be a real challenge, but essentially consists of maintaining good seals around the exterior. Once they are in your house there is not much that you can do, other than remove them. Like many of the other insects in the order Hemiptera (True Bugs) these bugs have a piercing sucking mouthpart and they are capable of using it in self-defense. In other words, handle them with caution. They can be knocked into a bucket of soapy water, vacuumed up, or just left alone. Of these three insects, BMSB is the only one that is a garden or agricultural pest.

In case you are unsure whether the insects in your home are BMSB, I have prepared the following table and photo guide to help you tell them apart. The shape of their hind legs, overall body shape, and color can be used to differentiate these three fall invaders.


Common Name Foods Body Shape Hind Leg Shape Color
Brown Marmorated Stink Bug Wide variety Pentagonal Long and thin Mottled brown tan and white
Western Conifer Seed Bug Seeds of conifers Elliptical Flat and broadened Mottled brown tan and white
Box Elder Bug Box elder and related maples Elliptical  Long and thin Black and red

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