8 February 2018 - URBANA, Ill.

Plant lovers are familiar with peat moss as the major component of potting mix, but harvest of the material is becoming unsustainable. Not only is peat being removed faster than it can re-form, its use in potting mix contributes to the release of carbon dioxide into the atmosphere.

“Peat bogs naturally store carbon. When peat moss is harvested, there’s a transfer of a global carbon sink into a net source. That’s because within a couple growing seasons, most of the peat moss from the potting mix is either mineralized by microbes or thrown out and decomposed. Either way, carbon dioxide is released,” says Andrew Margenot, assistant professor in the Department of Crop Sciences.

In a recent study, Margenot and colleagues from the University of California, Davis investigated a material called biochar as an alternative to peat moss in potting mix. Similar to charcoal, biochar is produced through a process called pyrolysis, or heating to high temperatures in the absence of oxygen. And like charcoal, it can be derived from virtually any organic substance.

“In our study, we used one made from softwoods from selective logging. But biochars can be made from corn stover, switchgrass, and lots of other organic waste products,” Margenot says. “Biochar could even be made from a greenhouse operation’s own waste, if there are trimmings from plants or old peat moss.” Margenot emphasizes that ‘biochar’ refers to a very broad class of material that can vary greatly in its properties depending on the pyrolysis temperature and the feedstock used.

When organic material decomposes naturally, the process releases carbon dioxide. But biochar decomposes very slowly, potentially on the order of centuries, so when organic material is turned into biochar, the carbon is essentially sequestered and can’t escape back into the atmosphere.

But how well does it work in potting mix? To find out, Margenot and his team grew marigolds from seed to flower in a number of experimental potting mixtures that replaced peat moss with an increasing proportion of commercially available softwood biochar.

In the biochar mixtures, pH soared. “The ones with lots of biochar had a pH up to 10.9, which is ridiculous for trying to grow things,” Margenot says. But this wasn’t unexpected for the type of biochar the researchers used.

Marigolds grew and flowered just fine, even when biochar replaced all of the peat moss in the potting mix. However, for plants growing with high concentrations of biochar, the early stages were a struggle.

Photo: Andrew Margenot and others found that biochar can replace peat moss in marigold production with no adverse effects. (credit: Andrew Margenot)

“You could see that the plants took a hit in the early stages of growth, the first two to three weeks. They were shorter and had less chlorophyll, indicative of a nitrogen deficiency, which you’d expect at such a high pH. But these plants caught up by the end. By flowering stage, there was no negative effect of biochar versus peat moss,” Margenot says.

Not only did the plants suffer no long-lasting negative effects of the biochar, the pH in those pots neutralized by the end of the study. Margenot thinks this could have been due to a natural process of ion exchange between plant roots and potting mix, naturally occurring carbonates in the irrigation water, or the use of industry-standard fertigation, irrigation with low levels of dissolved nutrient ions such as nitrate and phosphate, in the experiment.

Although he only tested one type of biochar in one type of plant, Margenot is optimistic about the promise of biochar in nursery applications. “Because we used a softwood biochar known for its high pH, we really tested the worst case scenario. If it could work in this case, it could probably work with others.”

The article, “Substitution of peat moss with softwood biochar for soil-free marigold growth,” is published in Industrial Crops and Products. Margenot’s co-authors, all from UC Davis, include Deirdre Griffin, Barbara Alves, Devin Rippner, Chongyang Li, and Sanjai Parikh.

Source: ACES News

Read more

Comments

No comments to display.

Related posts

Increasing investment in Australian AgTech pivotal to our economic success: report

A new report released today by the United States Studies Centre – the first of its kind –analyses the volume, value, and makeup of AgTech investment in Australia.

EU-funded scientists developed adaptable ground and aerial robots that can transform farming

Utilising the data delivered from the UAV, the UGV prototype, called Bonirob, autonomously navigates its environment and performs actions at set locations. For example, it can spray a pesticide onto a selected crop area, and in the case of weed presence, it can get rid of them mechanically, avoiding the use of dangerous herbicides.

Call for Applications: The Tech Startups Challenge for women inclusion in Africa

To promote entrepreneurial initiatives managed by women and/or men, tackling the challenges of women's inclusion and gender inequalities – whether social, economic, cultural or political – and leveraging digital innovation for their development.
Application Deadline in a month

Call for Applications: Travel tech start-ups in Europe

The Call TRAVEL-TECH INNOVATION CONTEST 2018 is looking for incorporated companies, operating (mainly, but not exclusively) in the field of Travel-Tech with expertise in INCOMING / INTEGRATION OF TRAVEL MANAGEMENT SYSTEMS with SPECIFIC EXPERIENCE IN BOOKING and API DESIGN/IMPLEMENTATION with an idea, a project and/or in any case able to help us to RENEW the process of interfacing Zani Viaggi’s booking with the different players of the national and international market to allow real-time bookings of the experiences in the portfolio in view of the specific administrative and tax requirements that the different domestic tax systems entail.
Application Deadline in 15 days

Tierion: Utilizing the Bitcoin Blockchain to Verify Documents

The Tierion’s development includes contributions from developers across the globe. The platforms code is open-source, and the development team invites programmers to help improve the coding.

SET Award 2019: Call for applications for top innovators in the energy transition

The SET initiative invites start-ups around the world to present their business ideas.
Application Deadline in 3 months

EU's Call for Proposals: ERANETs in agri-food

The agri-food sector needs to take more advantage of the potential of digital technologies. Relevant technologies may include Internet of Things, Artificial Intelligence, Big Data technologies, remote and localised sensing.
Application Deadline in 3 months

EU's Call for Proposals: Integrated storage systems for residential buildings

The combination of renewable energy with storage is key to support the next generation of very low or plus energy houses. Such storage equipment will be exploited first and mostly in the residential buildings (existing and new ones).
Application Deadline in 4 months

3D visualization of GIS data in coconut plantation management: challenges and opportunities

The aim of this paper is to reveal the existing challenges and find opportunities of online 3D visualization of GIS data in coconut plantation management.

Construction of an in-situ smart device that measures some basic environmental factors for agricultural monitoring

In this work, a portable and user friendly smart Automated Weather Station (AWS) was constructed. The device that is programmed with Arduino UNO is capable of measuring the temperature, relative humidity and moisture content of the soil.