Friday, March 29, 2019

Can Soil Microbes Slow Climate Change?


One scientist has tantalizing results, but others are not convinced.

This article was in Scientific American online but is worthy of being more widely dispersed into the wider agricultural and soil science community.  Worth a read!


By John J. Berger on March 26, 2019
Can Soil Microbes Slow Climate Change?

With global carbon emissions hitting an all-time high in 2018, the world is on a trajectory that climate experts believe will lead to catastrophic warming by 2100 or before. Some of those experts say that to combat the threat, it is now imperative for society to use carbon farming techniques that extract carbon dioxide from the air and store it in soils. Because so much exposed soil across the planet is used for farming, the critical question is whether scientists can find ways to store more carbon while also increasing agricultural yields.

David Johnson of New Mexico State University thinks they can. The recipe, he says, is to tip the soil’s fungal-to-bacterial ratio strongly toward the fungi. He has shown how that can be done. Yet it is not clear if techniques can be scaled up economically on large commercial farms everywhere.

Johnson, a trim 67-year-old microbiologist who is as comfortable using the latest metagenomics technology as he is shovelling cow manure into a composter, thinks society can only maximize carbon storage, increase soil’s water-holding capacity and grow plentiful crops if it restores the soil microbiome. “We currently have very degraded soils physically, chemically, but mostly biologically,” he says. “Microbes restore this balance.”

Johnson conducts precise soil-biology experiments into how to increase the capacity of agricultural systems to absorb carbon from the atmosphere. In a recently completed four-and-a-half-year field trial, Johnson planted fast-growing cover crops and applied a microbe-rich solution derived from a vermiculture (worm) compost produced in a low-tech composter of his own design. The bacteria, fungi and protozoa fed a soil food web of nematodes, microarthropods and other beneficial organisms.

Through photosynthesis, the cover crops pulled CO2 from the air, sank roots deep into the earth, and towered over the land. The results were unusual—and highly controversial. Johnson reported a net annual increase of almost 11 metric tons of soil carbon per hectare on his cropland. That’s equivalent to removing about 16 metric tons of carbon dioxide per acre from the atmosphere annually—roughly 10 times the increase that other scientists have reported in many different soils and climates.

Johnson ascribes these improvements, along with large increases in crop yields, to improved soil health stemming from the application of the microbes from his vermiculture, leading to an increase in the soil’s fungal-to-bacterial ratio.

Professor Rattan Lal of Ohio State University, widely regarded as a leading authority on soil carbon sequestration, says he was “intrigued” by Johnson’s outcome. “I want to understand why he’s getting such exceptional results.” Lal thinks that further, larger-scale trials are needed to validate Johnson’s work, of course.

Johnson is also conducting meticulous laboratory studies. They focus on the correlations among fungal-to-bacterial ratios and soil health, fertility and crop productivity. He reports finding increases in fungal-to-bacterial ratio, plus large increases in soil carbon and other nutrients as a result of his management practices.

In all this work, Johnson maintains that as the ratio of fungi to bacteria increases, the soil biome becomes more efficient in utilizing carbon and other nutrients and that the soil therefore releases less CO2 to the atmosphere. The jury is still out, however. Although peer-reviewed soil science literature contains some confirmation, other findings in submerged, forested and subarctic soils—admittedly different circumstances—failed to confirm the relation.

Keith Paustian, a professor of soil and crop sciences at Colorado State University, says he has seen some “quite high rates of carbon accrual” in degraded croplands that were converted to productive perennial grass systems. But he has not seen strong evidence that the same outcome can be produced by adding microbes.

EXTRAORDINARY CLAIMS
Johnson asserts that if his approach were used across agriculture internationally, the entire world’s carbon output from 2016 could be stored on just 22 percent of the globe’s arable land. He says that would provide net benefits of $500 to $600 per acre rather than net costs, if credits are provided for carbon capture and related benefits are counted, such as reduced irrigation and increased soil fertility.

To arrive at his global carbon-capture numbers, Johnson projected results from cropland plots of three to 75 acres of various soil types in five states. That is still a fairly limited sample. Henry Janzen, a research scientist at Lethbridge Research and Development Center in Alberta and a professor at the University of Manitoba, cautions that such a projection is risky. “Every ecosystem is unique,” he says. “A practice that elicits soil carbon gain at one site may not be effective at another. And always, the rate of carbon gain will depend on a host of interactive factors, including soil properties, previous management practices, climatic conditions and the vagaries of human whims.”

Janzen also points out that soils do not absorb carbon indefinitely. After some years or decades, they inevitably approach a new steady state. For that reason, he says, soil carbon sequestration is rarely seen as a long-term solution to increased atmospheric carbon dioxide concentrations.

Johnson acknowledges those factors but says managing soil to improve the health of its microbial life can provide strong carbon gains before the soil’s capacity levels off. He is in the process of scaling up his experiments to try to replicate his results on even larger plots in different geographies with a variety of cover and commodity crops, “to assess the impact for the rest of the world.”

A NEW PARADIGM?
Johnson’s work is based on a somewhat different paradigm from that of most conventional soil scientists. They often seek to boost agricultural productivity in traditional ways by adding fertilizer and using pesticides and herbicides as needed. This approach is anathema to Johnson. He decries almost every conventional farming practice—ploughing, bare fallowing, and the application of herbicides, insecticides and fungicides. All these, he says, “assault soil microbiota.” He claims that glyphosate (sold in commercial products such as Roundup) will kill Aspergillus fungal species in soil. Aspergillus is often regarded as a marker of fungal presence and is important in carbon and nitrogen cycling.

As for fertilizer, Johnson believes he has demonstrated that microbially inoculated soil enriched with tilled cover crops naturally accumulates more than enough nitrogen for vigorous plant growth. (Nitrogen is the limiting nutrient in most agricultural situations.) In one of his plots where he reports having increased net primary productivity five times, the soil accumulated 770 pounds of nitrogen per acre per year.

Much of this fixation is done by free-living nitrogen-fixing bacteria. Because a normal crop only requires about 180 pounds of nitrogen per acre, Johnson says it would be unnecessary to add artificial fertilizer to a system like this.

As with all of Johnson’s work to date, this result has appeared only in the form of reports and other “grey literature.” Harold van Es, professor of soil and water management at Cornell University’s School of Integrative Plant Science, is one of Johnson’s severest critics.

“In science, we strongly believe that research should be subjected to peer evaluation,” van Es says. “His ideas should not be at all presented as scientific facts.”

The fungal-to-bacterial ratio is indeed important, van Es says. “But there are many ways to increase that ratio,” not just Johnson’s approach. “Reducing tillage has similar effects and this has been much more widely documented.”

Although Johnson has irked some soil scientists and even aroused some ire, as climate change intensifies in speed and fury, many scientists believe it is important to leave no stone unturned in the search for ways to limit carbon emissions quickly. Perhaps the soil’s microbiome can be a powerful tool.

Rights & Permissions
ABOUT THE AUTHOR(S)
John J. Berger
John J. Berger is an environmental science and policy specialist who has written numerous articles and books about the environment and climate change. He is the author of Climate Peril, The Intelligent Reader’s Guide to the Climate Crisis.

Recent Articles
Crisis in the Cryosphere, Part 2
Crisis in the Cryosphere, Part 1


Published online here on Blogger with acknowledgments to the author and Scientific American online

Friday, March 08, 2019

Future Farming in Singapore. Can it Be Done in Darwin Too?

SINGAPORE - With global warming heralding new threats, resource scarcity will be the new normal.
So the Government is throwing its weight behind efforts to protect and provide for the country's survival - in the areas of water, making the most of waste, food and climate change research - Environment and Water Resources Minister Masagos Zulkifli said on Thursday (March 7).
"Climate change is bringing new and wicked problems," he said in Parliament.
And just like the country's water success story, the same can be done in other areas, through long-term planning decades before a problem surfaces, he said, pointing out that Newater was more than two decades in the making.
"Faced with a challenge, we start small, learn from others, harness technology, invest in R&D. Keep on trying, until we get it right.
"Then we take our solutions and scale up to benefit the whole nation."
In terms of food, this means decreasing the dependence on the global food market, which accounts for over 90 per cent of Singapore's current food supply.
Announcing an ambitious target of producing 30 per cent of the country's food needs by 2030 - or 30 by 30 - Mr Masagos said that this would call for new paradigms in the sector, with a focus on state-of-the-art indoor farms.
They would incorporate climate control and automation, for instance, and in terms of fish - closed containment systems that keep algae blooms and oil spills at bay.
"Farmers of the future will operate computerised control systems in a pleasant environment."
It was time to break away from the "take, make, use and toss" mentality and embrace the circular economy instead, Mr Masagos added.
Promising technologies dealing with waste include Singapore Polytechnic's green chemistry technology to recover precious metals in e-waste, and Nanyang Technological University's method of turning food waste into high-grade fertilisers.
In addition, the National Environment Agency is working on turning incineration ash into construction material, called NEWSand, and has developed draft standards for using treated ash for building roads, for example.
When it comes to climate change, science will be key in guiding policies, he added, with the opportunity for Singapore to be a leader in the tropics, since there is limited knowledge on its effects there.
To this end, there will be more investment to build capability in the Centre for Climate Research Singapore, set up in 2013, and the local scientific community. This year, the centre will embark on the National Sea Level Programme to better understand sea levels around Singapore, so that robust projections and plans can be made for the long term.
Solar power will be stepped up. It could be harnessed at reservoirs, coastal areas and building facades to potentially power 40,000 four-room flats each year, an area half the size of Tampines.
At the same time, the water story is also not over.
The Research Innovation and Enterprise Council has allocated $200 million to national water agency PUB for research, and the Government has posed "Big Hairy Audacious Goals" to the scientists, he said, such as producing desalinated water with much less energy than currently needed.
Already, new technology which could potentially halve the energy required for desalination is set to be scaled up and deployed in the Tuas Desalination plant from 2020.
At the same time, people are saving more water, with domestic consumption falling from 148 litres per person per day in 2016 to 141 litres in 2018, with a target of further shaving it to 130 litres by 2030.
In all, the Government will spend almost $400 million on research and innovation in water, the circular economy, climate change and food, under the Research, Innovation, Enterprise Plan 2020 (RIE2020).
The challenges also bring with them opportunities, Mr Masagos stressed.
Pointing to Singapore's thriving water industry - with over 200 companies and more than 25 R&D centres, he said that investments in the sector in the past decade had created 14,400 good jobs and economic value-add of over $2.2 billion annually.
And plans for the water, food and environmental sectors would open up a variety of exciting opportunities for enterprises and jobs.
"We must do as our forefathers did, stay alert and nimble, and continue to plan and prepare for the long term," he said.
"We have ambitious plans for our water, waste and food sectors, but the road ahead is long and winding. We will persevere, for we are not done building a sustainable Singapore."

Thursday, March 07, 2019

NEW - Requirements to Spray 2,4-D: Reduce the Risk of Damage.


Spray application and spray drift management is critical in using herbicide and pesticide products effectively and safely – for you as operator,  and both target areas being sprayed and non-target areas.   

As well, awareness of current or new label instructions for some products really mean users must up their performance to use best practice to reduce the risk of off-target spray drift and to incorporate the new label instructions for the use of 2,4-D.

The Australian Pesticides and Veterinary Medicines Authority (APVMA) suspended the labels of all products containing the active ingredient 2,4-D from October 4, 2018, replacing them with a permit.

Key changes for using 2,4-D under the permit include: applicators must now use at least a Very Coarse (VC) spray quality; when using a boom sprayer, boom heights must be 0.5 metres (or lower) above the target canopy; and downwind buffers now apply (typically less than 50 metres, subject to rate and product being applied) between application sites, and downwind of sensitive crops and environmentally sensitive aquatic areas.

While new procedures are focused on 2,4-D, common sense would indicate that related products also may need more appropriate care during spraying.   It might also lead to better overall outcomes and improved success for the target plants.

Six videos have been developed and are worth looking at to help users adapt to the changes.
Presented by respected spray consultant Bill Gordon, the new series of six videos cover the topics :
             2,4-D label changes
             A spray contractor’s experience
             Nozzle selection for larger droplets
             Weather conditions and the 2,4-D label
             Maximising spray coverage
             Maximising spray efficiency 

More information and links to the media are on a few web sites; this link should find the videos –

they are listed sequentially.

Useful for growers and spray users across many field crop species, horticulture, pastures and turf to help effective spraying and prevent problems – which could come back to hit you!

While specific to 2,4-D the principles really have wider ramifications and should improve overall herbicide spray operations.  Good sensible operational practice pays off with better outcomes.