Day: October 3, 2013

Biochar as a replacement for perlite in greenhouse soilless substrates

Download this Master’s Thesis from Iowa State University’s institutional repository.

Biochar is a solid, carbonaceous coproduct of the pyrolysis process used for biofuel production. Many field studies have shown improved chemical and physical properties of soil after amendment with biochar. The benefits of biochar may extend to soilless substrates used in the greenhouse industry, and the porous nature of biochar may make it a suitable replacement for perlite in greenhouse substrates. The objectives of this research were to determine the most suitable biochar particle size and percentage for use in a greenhouse substrate, to determine if biochar can eliminate the need for amendment with limestone, and to demonstrate plant growth in substrates with biochar as a component.

We obtained four sizes of prescreened hardwood biochar and blended each with sphagnum peat to create 40 substrates for experimental trials. The pH of leachate from each substrate was recorded over a 16-week period. Substrate pH increased as the percentage of biochar increased. At the same percentage of biochar in the substrate, decreasing the particle size of biochar increased substrate pH. Several biochar-sphagnum peat mixtures, without limestone amendment, led to a substrate pH appropriate for container-grown plants. Eight of the nine substrates selected for evaluation met recommended physical parameters for use in containers for greenhouse crop production. One substrate, 30% BC10 blended with 70% sphagnum peat, was similar to the control, Sunshine LC1 (Sun Gro Horticulture, Agawam, MA) in all measures except bulk density. Plants grown in biochar-containing substrates were compared to plants grown in a commercial substrate that contained sphagnum peat, perlite, and limestone (Sunshine LC1). Plants grew in each substrate for 27 or 35 days. Electrical conductivity and pH were measured 14 days after transplanting and at the end of each trial. Results varied among trials and crops grown. Many biochar-based substrates produced plants with shoot dry mass greater than or equal to the control. These results demonstrate the potential for biochar to replace perlite and eliminate the limestone amendment needed for commercial greenhouse soilless substrates based on sphagnum peat. Soilless substrates containing biochar as a replacement for perlite and limestone can successfully be used for greenhouse plant production.

A Systematic Review of Biochar Research, with a Focus on Its Stability in situ and Its Promise as a Climate Mitigation Strategy

Download the article, which appears in the open-access journal PLOS ONE.


Claims about the environmental benefits of charring biomass and applying the resulting “biochar” to soil are impressive. If true, they could influence land management worldwide. Alleged benefits include increased crop yields, soil fertility, and water-holding capacity; the most widely discussed idea is that applying biochar to soil will mitigate climate change. This claim rests on the assumption that biochar persists for hundreds or thousands of years, thus storing carbon that would otherwise decompose. We conducted a systematic review to quantify research effort directed toward ten aspects of biochar and closely evaluated the literature concerning biochar’s stability.


We identified 311 peer-reviewed research articles published through 2011. We found very few field studies that addressed biochar’s influence on several ecosystem processes: one on soil nutrient loss, one on soil contaminants, six concerning non-CO2 greenhouse gas (GHG) fluxes (some of which fail to support claims that biochar decreases non-CO2 GHG fluxes), and 16–19 on plants and soil properties. Of 74 studies related to biochar stability, transport or fate in soil, only seven estimated biochar decomposition rates in situ, with mean residence times ranging from 8 to almost 4,000 years.


Our review shows there are not enough data to draw conclusions about how biochar production and application affect whole-system GHG budgets. Wide-ranging estimates of a key variable, biochar stability in situ, likely result from diverse environmental conditions, feedstocks, and study designs. There are even fewer data about the extent to which biochar stimulates decomposition of soil organic matter or affects non-CO2 GHG emissions. Identifying conditions where biochar amendments yield favorable GHG budgets requires a systematic field research program. Finally, evaluating biochar’s suitability as a climate mitigation strategy requires comparing its effects with alternative uses of biomass and considering GHG budgets over both long and short time scales.

The Role of Social Entrepreneurship in Sustainable Business

Read the full story at Triple Pundit.

Typically, when we think about “sustainable business,” we concentrate on corporate social responsibility (CSR): energy efficiency, reduced carbon footprint, recycling and reuse, fair treatment of employees, and charitable giving, among other considerations. Most of the sustainable business programs, in the universities that have them, are corporate focused. Yet, corporations are not the only variety of sustainable businesses.

Sometimes sustainable business is manifested in the activities of startups and small businesses that pursue double and triple bottom lines. These are mission-driven companies that are dedicated to being socially responsible from their inception, unlike most (though not all) corporations that pursue CSR for marketing purposes or to cut costs and increase profits. While there is value in doing the “right” things, even if it is for selfish reasons, there is a certain purity about these social enterprises that has a special appeal for those of us who cherish people and planet as well as profits.

20 things you didn’t know you could recycle

Read the full story at Mother Nature Network.

From sandwich bags and bras to Crocs and crayons, there’s a whole lot more than bottles and cans that can be recycled.
As a reminder to any readers who live in or near Champaign County, Illinois, The I.D.E.A. Store accepts many household items as donations, including half-filled bottles of craft paint, used crayons, and puzzles/games with missing pieces. The store is operated by the C-U Schools Foundation.

Mosaic’s latest crowdfunding project lets you invest in the military

Read the full story at SmartPlanet.

Mosaic, the California startup that allows the public to invest in solar projects, is now letting folks put their money into a military solar installation.

People can invest—and then receive a return—in a 12.3-megawatt solar photvoltaic installation project across 547 homes at Joint Base McGuire-Dix-Lakehurst in New Jersey.

Video: Australian university produces zero emissions sports car

Watch the video from the BBC.

Students at the University of New South Wales, in Australia, have built a sports car powered by the sun.

The makers say it could be Australia’s first practical, zero emissions, car that harnesses solar energy.

Phil Mercer reports.