How can the use of plastics in agriculture become more sustainable?

Photo Credit: Mark Stebnicki

It is impossible to imagine modern agriculture without plastics. 12 million tons are used every year. But what about the consequences for the environment? An international team of authors led by Thilo Hofmann from the Division of Environmental Geosciences at the University of Vienna addresses this question in a recent study in Nature Communication Earth and Environment. The research shows the benefits and risks of using plastics in agriculture, and identifies solutions that ensure their sustainable use. 

Once celebrated as a symbol of modern innovation, plastic is now both a blessing and a curse of our time. Plastic is ubiquitous in every sector, and agriculture is no different. Modern agriculture, which is responsible for almost a third of global greenhouse gas emissions and is a major drain on the planet's resources, is inextricably linked to plastic. The new study from the University of Vienna was conducted by Thilo Hofmann, environmental psychologist Sabine Pahl and environmental scientist Thorsten Hüffer, along with international co-authors. Their research reveals that plastic plays a multi-faceted role: from mulch films that protect plants to water-saving irrigation systems, plastic is deeply embedded in our food production.

CRISPR/Cas9-Based Gene Drive Could Suppress Agricultural Pests

NC State researchers used a florescent protein to mark the genetic changes to spotted-wing Drosophila.
Photo Credit: Courtesy of the researchers / North Carolina State University

Researchers have developed a “homing gene drive system” based on CRISPR/Cas9 that could be used to suppress populations of Drosophila suzukii vinegar flies – so-called “spotted-wing Drosophila” that devastate soft-skinned fruit in North America, Europe and parts of South America – according to new research from North Carolina State University.

The NC State researchers developed dual CRISPR gene drive systems that targeted a specific D. suzukii gene called doublesex, which is important for sexual development in the flies. CRISPR stands for “clustered regularly interspaced short palindromic repeats” and Cas9 is an enzyme that performs like molecular scissors to cut DNA. CRISPR systems are derived from bacterial immune systems that recognize and destroy viruses and other invaders, and are being developed as solutions to problems in human, plant and animal health, among other uses.

Targeting the doublesex gene resulted in female sterility in numerous experiments as females were unable to lay eggs, says Max Scott, an NC State entomologist who is the corresponding author of a paper in Proceedings of the National Academy of Sciences that describes the research.

“This is the first so-called homing gene drive in an agricultural pest that potentially could be used for suppression,” Scott said.

Wild plants can adapt to agricultural propagation

Wild plants for restoration projects are propagated in culture.
Photo Credit: Ute Matthies

Researchers study rapid domestication of plants grown for seed production to restore ecosystems

Wild plants play an important role in the renaturation of degraded landscapes and ecosystems. The seeds for this are mainly propagated in specialized farms, similar to crops. A team of biologists led by researchers from the University of Marburg has now taken a more detailed look at how the farm production of seeds for restoration affects the characteristics of the species. Across as few as three generations, some species evolved signs of a so-called domestication syndrome - a suite of traits typically evolved by crops during domestication from their wild relatives. The observed changes across the first generations were primarily small and unlikely to compromise the quality of the currently produced seeds. Yet, it is the first warning that seeds of wild plants must be produced with caution and only for a limited number of cultivated generations before new seeds are collected from the wild. The results of the study have been published in the Journal PNAS.

The destruction of natural habitats is the greatest threat to biodiversity. More than half of the world's land area is already degraded. However, this dire state can be partially reversed through ecosystem restoration - the restoration of natural habitats on degraded land. Restoration measures include, for example, restoring forests by planting trees or restoring grasslands by sowing seeds. The seeds for these measures are usually produced in specialized seed farms.

Genetically Modified Plants Grow Better in Arid and Saline Conditions

Tobacco is one of the most well-studied plants by scientists.
Photo Credit: Rodion Narudinov

Russian scientists have modified tobacco. They added the AtGSTF11 gene and improved the plant's resistance to adverse conditions. These adverse conditions include low temperatures, drought and salty soil. Model plants with the new gene used in the experiments showed increased vitality. The scientists have published a description of their experiments in the Russian Journal of Plant Physiology.

Plant stress (caused by a variety of factors - drought, temperature, contaminated soil, etc.) ends at the cellular level with oxidative stress: reactive oxygen species are formed in the cell. They destroy proteins, disrupt the structure of DNA and lead to cell death or interfere with vital functions, the scientists add. There are cellular mechanisms that prevent the development of oxidative stress - low-molecular antioxidant compounds, proteins (antioxidant enzymes), glutathione.

"Glutathione is a short sulfur-containing peptide that plays an important role in protecting plants from stress. It is formed, then cycled into oxidized and reduced forms, and so on. This is the glutathione cycle. In this process, reactive oxygen species are eliminated and plant cells do not die. A number of genes are involved in this cycle. We added another gene, glutathione S-transferase, and got a more viable plant," says Bulat Kuluev, Head of the Plant Genomics Laboratory at the Institute of Biochemistry and Genetics (Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences).

Farming more seaweed for food, feed and fuel

Seaweed farmers in East Nusa Tenggara, Indonesia
Photo Credit: Eldo Rafael

A University of Queensland-led study has shown that expanding global seaweed farming could go a long way to addressing the planet’s food security, biodiversity loss and climate change challenges.

PhD Candidate Scott Spillias, from UQ’s School of Earth and Environmental Science, said seaweed offered a sustainable alternative to land-based agricultural expansion to meet the world’s growing need for food and materials.

“Seaweed has great commercial and environmental potential as a nutritious food and a building block for commercial products including animal feed, plastics, fibers, diesel and ethanol,” Mr. Spillias said.

“Our study found that expanding seaweed farming could help reduce demand for terrestrial crops and reduce global agricultural greenhouse gas emissions (GHG) by up to 2.6 billion tons of CO2-equivalent per year.”

Researchers mapped the potential of farming more of the 34 commercially important seaweed species using the Global Biosphere Management Model.

Turning Wastewater into Fertilizer Is Feasible and Could Help to Make Agriculture More Sustainable

Photo Credit: Franck Barske

The wastewater draining from massive pools of sewage sludge has the potential to play a role in more sustainable agriculture, according to environmental engineering researchers at Drexel University. A new study, looking at a process of removing ammonia from wastewater and converting it into fertilizer, suggests that it’s not only technically viable, but also could help to reduce the environmental and energy footprint of fertilizer production — and might even provide a revenue stream for utilities and water treatment facilities.

A Sustainable Nitrogen Source

The production of nitrogen for fertilizer is an energy-intensive process and accounts for nearly 2% of global carbon dioxide emissions. In the last several years researchers have explored alternatives to the Haber-Bosch nitrogen production process, which has been the standard for more than a century. One promising possibility, recently raised by some water utility providers, is gleaning nitrogen from the waste ammonia pulled from water during treatment.

“Recovering nitrogen from wastewater would be a desirable alternative to the Haber-Bosch process because it creates a ‘circular nitrogen economy,’” said Patrick Gurian, PhD, a professor in Drexel's College of Engineering who helped lead the research, which was recently published in the journal Science of the Total Environment. “This means we are reusing existing nitrogen rather than expending energy and generating greenhouse gas to harvest nitrogen from the atmosphere, which is a more sustainable practice for agriculture and could become a source of revenue for utilities.”

How farmers could fertilize more efficiently

A scheme showing the relationships of biological nitrification inhibition in the rhizisphere, improved nitrogen use efficiency and plant productivity, resistance, yield and quality.
Credit: Wolfram Weckwerth

Crops can directly contribute to improved nitrogen fertilization efficiency and reduced greenhouse gas emissions in agriculture

Nitrous oxide is a powerful greenhouse gas. Its global warming potential can be up to 300 times that of CO2 over a 100-year period. Globally, more than half of man-made nitrogen oxide emissions come from agriculture. A reduction in the nitrogen fertilizer used and an improvement in the nitrogen use efficiency of crops are therefore important measures in climate protection. An international team, coordinated by the Vienna Metabolomics Center (VIME) of the University of Vienna, is now presenting a new concept in the scientific journal "Trends in Plant Science" with which the efficiency of nitrogen fertilization is increased and the emission of nitrogen oxide (N2O) reduced.

The main goal of these new studies, building on many years of research, is to offer farmers a better economical alternative, where they can use crop plant derived biological inhibitors instead of highly polluting chemical fertilizers. An important task of the research is to better understand the complex root-soil microbiome ecosystem and to develop technological platforms that can use a root-soil balance for sustainable next-generation agriculture. The international team led by the University of Vienna has now taken an important step in this direction.