Healthy Soil & Microbes Make It Rain?
February 11, 2017
The importance of building healthy soil is greater than organic growing. Even conventional growers are discovering this too. But the idea that organic soil matter will make it rain? Not just the soil, but the microbes it contains, and the ones that live on plants too.
Scientific evidence that this is very possible is building, beginning with a discovery in 1978 that most scientists totally ignored. The entire concept being just too far-fetched to grasp. Things have changed in the past decade or so. And it’s all very interesting.
Fighting a losing battle with wheat disease, plant pathologist Dave Sands from Montana State University wondered if the cause of his dilemma was coming out of the clouds. So he took a Petri dish up there and collected some cloud. Sure enough, the disease that no agricultural product could prevent was riding around in the sky.
Dave’s theory was that pathogenic bacteria was seeding clouds and making it rain on the perfect host to thrive. His contemporaries, however, weren’t copacetic. Everyone knew that dirt particles and soot are what make it rain. Plant harming microbes in the clouds controlling the weather? Total nonsense!
Apparently not, because in the past few years more scientists have found that Sands was on to something 40 years ago. Clouds are literally teeming with hundreds of different kinds microbes! And most of them are very much alive. This is known as “bioprecipitation” – though Wikipedia identifies it as mostly plant pathogens. But the page isn’t current. Not with already dated references retrieved in 2011. A lot can happen in science over 10-15 years.
Only about 40% of the clouds in the sky can make it rain. They have to contain ice – whether precipitation fall is rain, hail, or snow. Some airborne microbes can efficiently catalyze ice formation (a.k.a. biological ice nucleators or IN).
In February 2008, professor of biological sciences Brent Christner from Louisiana State University published the results of a study of bacteria that make it rain in the journal Science. Working with colleagues in Montana and France, the scientists examined precipitation from locations around the world. They found rainmaking bacteria all over the place and established that the most active ice nuclei are biological. They found that unlike dirt and soot particles, the microbes can catalyze freezing at warmer temperatures.
“These biological particles could factor heavily into the precipitation cycle, affecting climate, agricultural productivity and even global warming… If present in clouds, biological ice nuclei may affect the processes that trigger precipitation.” — EurekAlert, 28-FEB-2008
The press release goes on to say that this idea of bacteria that make it rain is not so crazy. In fact, snowmaking at ski resorts had already been done using ice-nucleating bacteria for over 60 years at this point.
In January 2009, National Geographic News ran the story, Rainmaking Bacteria Ride Clouds to “Colonize” Earth? Here the evidence that bacteria may be part of a constant feedback between far-flung ecosystems and clouds is reported. A fact that, at the time, Christner told journalist Christine Dell’Amore was “sending ripples through the atmospheric science community.” These nucleators were traced from the clouds to the source; the soil and plant ecosystems on the ground.
One such ripple being expressed by Roy Rasmussen, senior scientist at the National Center for Atmospheric Research. He wasn’t buying the theory – it wasn’t verified, even though snowmaking involved the very same kind of catalyst. But Dave Sands, who had never stopped investigating this feedback loop between the ground and the clouds was beginning to think that drought and microbes are connected. Tired soil that’s overgrazed or overworked lacks bacteria, a situation that “could limit clouds’ ability to shed rain.” It might even be the very choice of species planted. But – proving this required more work.
Just 3 months later in April 2009, Oxford’s peer-reviewed journal BioScience published the paper, How Forests Attract Rain: An Examination of a New Hypothesis. Here’s another controversial idea – that plant foliage influences the hydrology cycle. The study that supported this theory didn’t look at any type of microbe. The focus was how much the removal of even a very localized loss of forest could change the weather of an area as large as a continent.
With that in mind, coupled with Dave Sands’ suggestion that even the species planted can affect the population of microbes that make it rain… Yes, foliage could very well have a huge influence on whether a geolocation gets sufficient rainfall, or evolves to having an arid climate. Furthermore, the healthiest soil naturally regenerates its own fertility and microorganism population in perfect balance to sustain the plants rooted in it into perpetuity. It is found in a forest or grassland.
This natural cycle has existed without any assistance from man. It’s the very reason that forests and prairies cover land masses. And for that to happen without some form of assistance, the ecosystem would have to have a method of calling for moisture when it’s needed.
So, this isn’t really so far-fetched at all. Amazing, yes. Crazy, no. Just way more complex than anyone realized – until recently. But back to the discoveries leading up to the current week…
In 2012, Brent Christner had more details on microbes that make it rain to share. Scientific news periodical Microbe published his highly interesting Cloudy with a Chance of Microbes paper in Volume 7, Number 2.
“Microbes can be aerosolized from virtually any surface and transported both horizontally and vertically in the atmosphere. They are ubiquitous in the near-surface and free troposphere and are found in clouds at concentrations of about 104 cells m3. There are even reports of viable bacteria and fungi being collected from 10- to 50-km altitudes in the stratosphere and 50 to 100 km above the Earth in the mesosphere. Nevertheless, very little is known about the flux, abundance, and diversity of microorganisms in the Earth-atmosphere system.
Remarkably, certain atmospheric conditions may support microbial growth. Rates of heterotrophic production in supercooled cloud droplets suggest that cloud-borne bacterial biomass has the potential to increase by as much as 20% per day. Hence, microbes and their metabolic activities could affect meteorological processes in the atmosphere both by changing cloud chemistry and serving as nuclei for precipitation.”
The biggest issue Rasmussen (National Center for Atmospheric Research) had back in 2009 was whether the concentration of microbial cells was big enough to actually have a significant influence on precipitation. By 2012, Christner and associates from around the world had compiled enough data to provide evidence to override that skepticism.
“Enormous numbers of cells – 1024 to 1026 – of microorganisms inhabit leaf surfaces globally. About one-third of the ice crystal residues in clouds sampled over Wyoming are biological particles, providing direct evidence for the involvement of bacteria, fungi, and/or plant material in ice-cloud processes…” Additionally, the active ice-nucleators over the Amazon rainforest are different. Biological particles dominate above -25C with mainly secondary organic aerosols from volatiles produced by land plants and animals as cloud condensation nuclei.
So, the purpose of clouds is much more diverse than evaporation and transpiration collection. In fact, the research done up to this point in time shows that the atmosphere is fundamental to microbe dispersal, and the clouds themselves support cell reproduction. In addition to airborne microbes and their metabolic activities affecting the weather.
Naturally, this is just the discovery of a new frontier to study, but it was enough evidence to grab the attention of more scientists. By 2013, atmospheric chemist Kim Prather at the University of California, San Diego was analyzing the chemical composition of IN in the most rain-laden clouds over the Sierra Nevadas, in Wyoming, and on the island of St. Croix in the Carribean. About 40% were biological, often coinciding with dust from as far away as Africa and China, and typically from desert regions.
“In one instance,” she tells New Scientist in April 2016, “we were able to see the dust traveling across the Pacific, and anticipate the subsequent snowfall.” The journalist, Kate Ravilious, goes on to say that this and earlier research discoveries “amounts to tantalizing evidence that microbes do indeed seed ice in warm clouds… though she has yet caught bacteria in the act.”
Next, Ravilious shares that in 2015, Daniel O’Sullivan at the University of Leeds proved that fungi particles are also up to the task. And soil is a huge reservoir of them. Some microscopic phytoplanktons in the ocean are also ice nucleators. How would they get into the clouds? Easily, after being tossed into the air in the spray from waves.
The researchers weren’t implying that microbes control explain Earth’s weather, but Christner points out that “microbes don’t have to control global precipitation patterns to influence certain regions… I think there are certain conditions and times of year when these things load up the atmosphere and have a significant effect.”
So, this is where soil microbes enter into the greater scheme of things. And here’s a fascinating theory from this article… Environmental microbiologist Cindy Morris, the colleague of Brent Christner, suspects that the 1930s Dust Bowl drought was brought on by the type of wheat farmers grew. It was highly susceptible to rust. She feels that with so much of it planted in the region, enough bacteria became airborne during plowing to cause “so many ice nuclei that they constipated the clouds.”
Two weeks later, New Scientist published another article by Ravilious, Rain spawns more rain when it falls on ploughed land. Now she’s concentrating on soil microbes due to a paper published in the journal Nature Geoscience. Scientific research in 2015 found that rainfall stirred up particles in soil. Now Alexander Laskin and colleagues at Pacific Northwest National Laboratory in Washington analyzed what happens when rain falls on turned soil.
The results of this study found that rain flung organic particles in the air via bubbles formed when raindrops hit forming puddles. However, this only takes place in light to moderate rainfall. A heavy rain hits the puddles on the surface so hard that little air bubbles form.
Additionally, scientists in Australia found that rainfall increases the probability of further precipitation in the days that follow the original event. Hence, “rain spawns more rain.”
The abstract for this last research article she referenced, published in Atmospheric Chemistry and Physics, notes that the period of recurring precipitation was commonly shorter after 1960. Particularly downwind from coal-fired power plants. An interesting observation, given that soot supposedly induces rain. A distinct line drawn between 1959 and 1960 with more recurring rain before it than after? That’s only about a decade after farmers started switching from old practices to synthetic fertilizers. This could point to where it headed into mainstream, because soil microbes don’t know what to do with man-made fertilizer.
And here’s what started me on the journey we’ve made to this point on the page. The trip has become longer than I ever anticipated, but I hope you’ve found it as fascinating as I have…
From Beef Producer just a few weeks ago – More soil organic matter makes more rain. Interesting. Big Beef and organic soil building seem an odd pairing. Definitely, a must-check-it-out.
Mr. Newport opens with what a huge reward better soil management offers if up to half of the rainfall in North America comes from evapotranspiration of plants and soil. As some meteorologists say, that is. And since that organic matter increases the amount of moisture a soil can hold, large expanses of healthy soil should make it rain more often.
The inspiration for his article? The recently published conclusions drawn from the first year’s satellite data from NASA’s Soil Moisture Active Passive (SMAP) project. The analyzation surprised the scientists involved. The data will help them in climate modeling, weather forecasts, and monitoring agriculture.
People involved in the SMAP project refer to the moisture held in the top 2-inches of soil following rainfall as “soil memory.” Why not call it moisture retention? Everyone else in the world does. Anyway… they thought that this memory lasted only a few hours. So, finding that one-seventh of that moisture remained 3 days later was unexpected. Especially with the greatest persistence found in the driest regions of the planet.
“I’ll remind you this is from depleted soil,” Newport says, “which today is the standard the world over. What if we were dealing with healthier soil, with higher organic matter?”
Time for a little math. Start with increasing soil’s organic matter by 1% to raise moisture retention per acre by 20,000 gallons. Multiply that by the acreage in his home state, then again by that one-seventh number from the SMAP data. And well, Oklahoma could have an extra 127.8 billion gallons of water for plants to use, air conditioning, and increasing potential rainfall.
Amazing, right? Alan Newport is now totally sold on the idea of building soil for grazing and crops. And he sees that it’s not just a benefit for the cattleman or farmer, but for everyone. Because organic matter in the soil can make it rain… more. Higher yields, lower inputs, more profit, and greater drought resilience.
As we all know, if you’ve got organic matter in soil and refrain from using pesticides, you’ve got oodles of beneficial microbes. Their job is breaking down soil organic matter into nutrients plants can access. But they can only go about their business when the soil is warm and some moisture is present. But since insecticides and fungicides can eradicate most, even all, of these good microorganisms in the soil. And since the greater share of land on this planet is depleted of organic matter or continuously exposed to pesticides, what they’re finding is a mere fraction of what once was, or what is possible.
Wouldn’t it be awesome if most conventional farmers in North America got as excited about building soil as Alan Newport? Unfortunately, the more likely scenario is… This knowledge leads to seeding clouds with lab-cultured, even genetically modified microbes. Designer rain. Life could get a lot more costly.
Tomorrow’s forecast… Mostly sunny morning hours with increasing clouds throughout the afternoon. There’s a 90% chance of Franken showers from 6-8 p.m. Clearing overnight.
More Info & Sources:
- EurekAlert (2008)
- National Geographic News (2009)
- BioScience, Vol. 59, Issue 4 (2009)
- Atmospheric Chemistry and Physics (March 2015)
- Cloudy with a Chance of Microbes (Microbe News 2012)
- New Scientist (May 2016)
- Beef Producer (2017)
- MIT News (SMAP Study 2017)
Top image courtesy of cliparts.
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