Daily Archives: 13th of September 2012

Extreme thermal weed control

Image: From the Synopsis of Histories by John Skylitzes, 12th century.

Image: From the Synopsis of Histories by John Skylitzes, 12th century.

Ever mindful that we ought to pursue environmentally friendlier methods where at all possible, I’ve been scouring the literature on your behalf. Well, a search for a ‘greener’ method of weed control may have ended with Anne Merete Rask’s recently defended University of Copenhagen (Denmark) PhD thesis entitled ‘Non-chemical weed control on hard surfaces: an investigation of long-term effects of thermal weed control methods’. Rather than use nasty chemicals, the research proposes that hot water/steam or heat should be used to ‘deal with’ those pesky plants (aka ‘weeds’) in hard-surface situations (i.e. not your typical arable setting). But you won’t get away with a single application: you need to apply the extreme temperature treatment up to six times in a season. So, go on, dust off that flamethrower and release the inner arsonical phytocidist that lurks within us all! And don’t stint on the treatment, either – mildly scalding or merely singing the plants might actually encourage regrowth of grass weeds. As is often the way with non-UK, European PhDs some of this work has already been published by Palle Kristoffersen et al.. And if you’re now inspired to read what is effectively the thesis’ introduction, check out a review of non-chemical control of weeds on hard surfaces by Rask and Larsen.

Transparent soil. Cool.

Transparent soil I tend to discourage students from using the term “cool” if formal scientific writing, but if I had to sum this paper up in one word, it would be …. cool.


Transparent Soil for Imaging the Rhizosphere. (2012) PLoS ONE 7(9): e44276. doi:10.1371/journal.pone.0044276
Understanding of soil processes is essential for addressing the global issues of food security, disease transmission and climate change. However, techniques for observing soil biology are lacking. We present a heterogeneous, porous, transparent substrate for in situ 3D imaging of living plants and root-associated microorganisms using particles of the transparent polymer, Nafion, and a solution with matching optical properties. Minerals and fluorescent dyes were adsorbed onto the Nafion particles for nutrient supply and imaging of pore size and geometry. Plant growth in transparent soil was similar to that in soil. We imaged colonization of lettuce roots by the human bacterial pathogen Escherichia coli O157:H7 showing micro-colony development. Micro-colonies may contribute to bacterial survival in soil. Transparent soil has applications in root biology, crop genetics and soil microbiology.