The researchers used next generation sequencing of the DNA in soil from samples taken across the site that had a range of plantings between six and 10 years old.
The technique – high-throughput amplicon sequencing of environmental DNA (eDNA), otherwise known as eDNA metabarcoding – identifies and quantifies the different species of bacteria in a sample.
The researchers – students Nick Gellie and Jacob Mills, Dr Martin Breed and Professor Lowe – analysed soil samples at the restoration site at Mt Bold Reservoir in the Adelaide Hills, South Australia, and compared them with neighbouring wilderness areas as ‘reference sites’.
“We showed that the bacterial community of an old field which had been grazed for over 100 years had recovered to a state similar to the natural habitat following native plant revegetation – an amazing success story,” says Dr Breed, Research Fellow in the Environment Institute.
“A dramatic change in the bacterial community were observed after just eight years of revegetation. The bacterial communities in younger restoration sites were more similar to cleared sites, and older sites were more similar to the remnant patches of woodland.”
Revegetation rewilds the soil bacterial microbiome of an old field – Gellie – 2017 – Molecular Ecology – Wiley Online Library
Planet’s satellite network captures a lot more imagery than has typically been available, and on a more frequent basis – it can collect a new snapshot of every piece of land on Earth daily, via its network of 149 orbital satellites.
Crops all over the world are susceptible to infection by fungi of various Aspergillus species, a fungus that produces secondary metabolites known as aflatoxins. These compounds have been implicated in stunting children’s growth, increasing the risk for liver cancer, and making people more susceptible to diseases such as HIV and malaria.
“Aflatoxin is one of the most potent toxins on the planet,” Schmidt said. “Usually it won’t kill a person outright, but it can make you very sick.”
Schmidt and her team set out to study whether a naturally occurring biological mechanism called RNA interference could be used as a weapon against the Aspergillus toxin.
The modified corn plants carry a genetic blueprint for small RNA molecules, each only about 20 base pairs long, only in the edible kernels, not the whole plant.
“The corn is constantly producing that RNA during the entire development of the kernel,” Schmidt explained. “When the kernels come in contact with the fungus, the RNA moves over into the fungus.”
Once inside the fungal cells, the hairpin-shaped RNA molecules pair up with corresponding target sequences of the fungus’ own RNA that code for an enzyme needed for toxin production, in a process called RNA interference. This causes the toxin production to shut down, but does not in any other way impact the fungus, which continues to grow and live on the corn, albeit harmlessly.
Small Molecule Could Have Big Future in Food Security
A new study finds:
- Organic Green Manure and Organic Animal Manure treatments increased cumulative water infiltration by about 10 times compared with the conventional farming treatment
- Soil aggregates increased by 50% with the Organic Green Manure and by 30% with the Organic Animal Manure treatments in the upper 15-cm depth
- At the same depth, bulk density was 3% lower under organic practices than in the conventional farming treatment, suggesting that organic farming reduces the soil’s susceptibility to compaction.
Organic Farming and Soil Physical Properties: An Assessment after 40 Years
A new study using a LARGE dataset has found for corn and soybean:
- Analysis of 748,374 yield records showed a 4.3% yield penalty for continuous corn.
- Corn yield penalties were more severe in areas with low moisture and low yields.
- Continuous soybean showed a 10.3% yield penalty, worse in low-yielding years.
- Corn yield penalties grew with up to 3 yr of continuous cropping, but not more.
- Soybean penalties increased monotonically with number of years continuously cropped.
Continuous Corn and Soybean Yield Penalties across Hundreds of Thousands of Fields