Home Grown Biofertilizer

The role that soil microbes (archaea, bacteria, and fungi) play in soil nutrient availability is an interesting area, one where we have much to explore. Biofertilizers are increasingly available commercially, meaning those of us outside the academic community will have increasing opportunity to conduct our own reseach. From Montana State University:

Some soil bacteria and fungi can access otherwise unavailable phosphorus, and some are commercially available. In a study on barley, one of these bacteria increased phosphorus availability by about 10 percent. In another study, a phosphate-solubilizing fungus was found to increase spring wheat grain yield by nine percent. "For both studies, the economics need to be considered to determine if these increases are worthwhile, and additional research is needed to determine the effectiveness of these products for different crops and soils," Jones said.

Growing your own biofertilizer may not be that difficult, depending on what it is you are trying to grow. Pictured is some compost tea starter I am "growing" for tomorrow's 36 hour run of actively aerated compost tea. I am going for a fungi-rich tea. Since the aerated tea process favors population growth of bacteria (and, one would think, archaea) over fungi, I am giving the fungi a boost before I start the tea. To 2 cups of compost, I have mixed in 3 tbs oat bran (the white flecks) and 1 tsp of T and J Enterprises (Spokane, WA)'s trichoderma rich "Soil Life & Activator" mix. As you can see the fungi is doing mighty fine. My first couple runs at promoting fungi growth were not as successful. By the looks of this one I am starting to get the hang of it.

Technorati Tags: fungi bacteria garden microbiology organic phosphorus soil

Teaming with Microbes Arrived Today

My anticipated copy of "Teaming with Microbes" has arrived. While I can't comment on the full text with any authority yet, I can say that it is well organized and has an extensive index (8 pages). It pleased me no end to see "soil science 28 - 42". There is also a valuable guide to labs and suppliers (4 pages). A supplier of mycorhhizal fungi here in Spokane is going to be getting a new customer.

My current soil obsession, bio-char, the foundational ingredient in terra preta nova, is disappointingly not mentioned. I have gotten the impression that Elaine Ingham, who has achieved demi-goddess standing in soil-web circles, was unswervingly skeptical of charcoal in large volumes as a soil amendment at the time the book went to publication, so I am not particularly surprised. In the post I saw, she based her concern on charcoal's high C:N ration putting soils out of balance. I'm chalking this up to fear of the unfamiliar. Too bad. Elaine Ingham is highly influential. When she comes around, her endorsement will save lives.

My restaurateur grandfather had a personal test to see if a chef was up to his standards: if the butter dish arrived without ice, he lowered his expectation that anything else could be properly prepared. I make similar menu-wide judgements on my orders of eggs-over-easy and chile rellenos. My acid test for an elightened organic gardening book is the treatment of glomalin (recalcitrant mycorhhizal fungally produced glycoprotein that accounts for 1/3 of world soil carbon). It is mentioned on page 37 (see familiar glomalin photo on page 39), so things are looking up at this point.

Tech Tags: bacteria book review environment fertility fungi garden glomalin microbiology new organic science soil

Invasive Earthworms

Its in the news. Research shows that invasive earthworms are damaging forest soils and are a menace to species diversity. Brought to light in November, 2002, gardening experts have confirmed the concern and the news keeps spreading. Fortunate for inquiring minds, self-archived copies of published journal articles are available. The problem is most often associated with formerly glaciated regions, where native populations of earthworms are not present. One work has a general map of affected locations (can compare to map here).

Another work addresses damage to soil. Comparing soil in front of the invaders to post invasion conditions demonstrates that these worms cause soil compaction, reduce soil fertility, increase erosion. Alterations in the soil profile include thickening of A horizons and obliteration of E horizons. I am still processing this information, but it appears that these invaders are capable of alterations deep enough into the soil profile to result in a change in soil taxonomic classification at the order level.

What looks to be one of the more prominent invasive species, Lumbricus rubellus showed up in my maple leaf compost (now vermicompost). I can confirm that L. rubellus is voracious. I remember a shovel slice of some nearby soil that went in a week or so before L. rubellus showed so my guess is they came with the place. L. rubellus operates on the surface litter and organic material found where that layer rests on the mineral soil. There are strong indications that L. rubellus supplements its leafy diet by feeding on the fungi and bacteria in the rhizosphere of plant roots. Seeing first hand how these critters operate, I find this last aspect quite disturbing. With its carbon sequestration function and the highly mutualistic species that it supports, this planet needs all the rhizospheric biological capacity it can muster.

Glomalin, science, CO2 and climate change

Atmospheric CO₂ concentration is expected to increase by 50% near the middle of this century. Indications are strong that rising CO₂ effects higher soil organic carbon content in some cases. Glomalin, which accounts for 1/3 of soil carbon, is of particular interest because of its important role in binding soil aggregates and increasing nitrogen use efficiency. The Center for the Study of Carbon Dioxide and Global Change has updated their excellent summary about the CO₂ - glomalin relationship. There is a great reference list to dive into.

Image source: USDA-ARS: Glomalin: A Manageable Soil Glue (pdf brochure)

Tech Tags: soil microbiology health mycorrhizal fungi glomalin climate change global warming environmental information

New organic garden book: Teaming With Microbes

For over 30 years, Jeff Lowenfels has written a free-lance gardening column in Anchorage. Among other things, Lowenfels and a couple of like-minded friends have patented a cool one-eye device for looking at plants and insects in the field, the macroscope, available now through Brunton. Lowenfels now has a forthcoming book on soil microbes, a subject he has written and lectured on abundantly for the last 5 years. He has been promising a book on this for most of those years and a lot of gardeners are looking forward to it. The subject of microbes and plant nutrition offers a lot to get excited about. I've mentioned some bits a time or two. And, as back40 reminds us, it was only in 1996 that glomalin was discovered. Glomalin is the durable soil carbon produced by mycorrhizal fungi and responsible for many positive attributes of soil function, plant nutrition and soil health.
According to a news article this week, Lowenfels book "Teaming With Microbes: A Gardener's Guide to Using the Soil Food Web." is being published by Timber Press and is due out sometime in late summer. Tag me "easily entertained", but I really like the double sens of the word "teaming" in the book title. In 2004, the working title was "Soil Science for Gardeners", and thankfully Lowenfels has wisely prevailed upon Timber Press to use "Teaming With Microbes" as he originally proposed.

Tech Tags: soil science research health fertilizer nutrition microbiology fungus glomalin bacteria nematodes new organic garden book microbes

Diversity

The current round of research into soil microbial life holds the door open onto insights that stagger the imagination.
Discoveries about vesicular arbuscular mycorrhizal fungi (VAM) and arbuscular mycorrhizal fungi (AMF) transformed our understanding of the contribution of soil fungi to soil function. Current research indicates that similarly monumental discoveries may await us.

Genome research and computational improvements demonstrate that the number and diversity of soil bacteria species far exceed the levels anticipated.

Bacteria make up the bulk of life on Earth and play a vital role in the lives of other organisms. But scientists have barely scraped the surface when it comes to identifying bacteria – 99% of species cannot be grown by standard techniques in the laboratory. ... Soil is ... a complex microbial environment containing thousands of distinct species – most of them bacteria – in just a half-gram sample.

and

More than one million distinct genomes occurred in the pristine soil, exceeding previous estimates by two orders of magnitude.

The distribution of this diversity is unequal in ways that may seem counter intuitive. The following was reported earlier today in What's New in Science and Technology .

Ironically, in the diversity of soil bacteria, the otherwise species-rich Amazon is a more like a desert, while the arid desert is a teeming microbial Amazon, researchers have found. Their first-ever continental-scale genetic survey of soil bacteria revealed that the primary factor that seems to govern the diversity of soil bacteria is soil pH. Thus, the acidic soils of topical forests harbor fewer bacterial species than the neutral soils of deserts.

The researchers said that, since soil bacteria play a fundamental role in a vast array of ecological processes, their survey constitutes an initial step in a new research pathway to understanding that role.

As exciting as these studies are, they are tentative and simplistic in comparison to the dynamic they reveal. These results are the product of capacity building needed before the real work can begin.

Technorati Tags: Soil science Microbiology Research