CONTENTS Acknowledgments
ix
Introduction: Fungal Consciousness
1
Chapter One—Mycorrhizal Ascendancy
5
Mycorrhizal Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Fungal Adaptability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Propagules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Nutrient Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Hyphal Lysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Chapter Two—Healthy Plant Metabolism
27
Phytochemical Progression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Natural Plant Defenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Plant Metabolites and Human Health . . . . . . . . . . . . . . . . . . . . . . 47
Chapter Three—Underground Economy
49
Dancing in the Street . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Mycorrhizal Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Innate Intelligence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Nondisturbance Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Chapter Four—Provisioning the Mycorrhizosphere
69
The Glomalin Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Fungal Foods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Mineral Investment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Moisture for Every Plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
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Chapter Five—Fungal Accrual
89
Inoculum Nuance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 Carbon Pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Hugelkultur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Biochar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Phosphorus Addendum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Chapter Six—Practical Nondisturbance Techniques
111
Garden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Landscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 Orchard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 Forest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 Farm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Chapter Seven—Edible Mycorrhizal Mushrooms
183
Chapter Eight—Soil Redemption Song
195
Soil Health Resources 201 Notes 203 Glossary 227 Bibliography 231 Index 233
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MyCo r r hi z al asCe n dan Cy
11111111111111111111111111111111111111111111111111111111111111111111111111 2 3 2 3 The Pace of Mycorrhizal discovery 2 3 2 3 2 3 2 Humans took note of the association between root chambers have revealed more about the 3 2 3 complexities of nutrient transfer and mycor- 3 2 fungi and the roots of plants in the middle 2 of the nineteenth century. A Polish botanist 3 rhizal networking. 2 3 Great dedication has gone into figuring 3 2 named Franciszek Kamieński recognized 2 this union as a symbiosis in 1881. Further a few things out about the robust web of life 3 2 3 beneath our feet. What’s wonderful is realizing 3 2 research was carried out by Albert Bernhard 2 Frank, who introduced the term mycorrhiza there’s so much more yet to be discovered about 3 2 in 1885, while investigating truffle produc3 the fungal underpinnings of plant health. 2 3 2 tion for the king of Prussia. Improvements 3 2 made around this time to the compound 3 2 3 2 microscope allowed observers to see hyphal 3 2 interaction with roots on a cellular level. 3 2 3 2 Revue Generale de Botanique published a series 3 2 of outstanding drawings detailing endo3 2 3 2 mycorrhizae made by I. Gallaud in 1905. 3 2 Decades would pass as conventional thought 3 2 slowly adapted to the idea that fungi could be 3 2 3 2 something other than bad for plants. 3 2 Functional discoveries began to come along 3 2 3 2 by the 1950s. Early research focused princi3 2 pally on nutrient uptake and the formation 3 2 3 2 of ectomycorrhizae. Attention began to shift 3 2 equally toward arbuscular mycorrhizae by 3 2 3 2 the 1970s. Published papers started coming at 3 2 a consistent pace as soil scientists and mycol3 2 3 ogists built on a foundation of knowledge. 2 3 2 Field studies began to encompass an ecologi3 2 cal point of view by the 1990s. More recently, 3 2 3 2 insights gained through molecular biology 3 2 have opened windows into the taxonomic 3 The microscope provided a first view of 2 3 2 relationships of species and (shamefully) 3 arbuscular fungal-root interactions a mere 2 genetic manipulation. Compartmentalized 3 century ago. Illustrations by I. Gallaud (1905). 2 3 44444444444444444444444444444444444444444444444444444444444444444444444444
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Myco r r hi z al A sc e n dan cy
on forest soils.5 Some ecto-oriented plants are not exclusively colonized by EM fungi, which opens the door to even more fungal interaction. The ability to secrete hydrolytic enzymes that degrade organic molecules to secure nitrogen reveals the dual nature of EM fungi. Saprotrophic (decomposition) fungi are not mycorrhizal as a rule. On the other hand, mutualistic fungi must be able to enter into root space to share these nutrients without triggering plant defenses. Outright saprotrophs are unable to do this. The explanation lies in the distant past. EM fungi and trees share similarities across all continents, suggesting that this symbiosis began some 160 million years ago.6 Numerous gene lines in EM fungi trace back to white and brown rots (see page 72 in “Soluble Lignins�) noted for serious breakdown jive.7 Apparently, some of the early decomposition fungi to come on the tree scene (as organic matter began
to accumulate) switched modes and evolved a symbiotic behavior. These fungi lost the ability to degrade plant cell wall polysaccharides (principally cellulose and pectates) while gaining the ability to enter intercellular spaces in the root in exchange for mineralized nutrients. This developmental pathway brought about EM fungi with entirely different traits from those of AM fungi. The mantle (fungal sheath) of interwoven mycelium on the surface of the finest roots is often visible to the unaided eye or by use of a hand lens. The fungi fit to the root tips like fingers on a glove. An internal network of hyphae, known as the Hartig net, weaves between the cells in the root. The penetration depth of this nutrient exchange structure differs between angiosperms and gymnosperms. Most angiosperms (deciduous species) develop a Hartig net confined to the outer epidermis, which is often radially elongated. By
EXPLORER HYPHAE
RHIZOMORPH
ROOT HAIR
HARTIG NET MANTLE
XYLEM CORTEX
EPIDERMIS
Ectomycorrhizal fungi sheath the outside of tree roots and accomplish nutrient exchange by means of the Hartig net structure reaching between root cells.
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Myco r r hi z al A sc e n dan cy
Left, spores of Glomus deserticola and, right, spores of Gigaspora margarita. Courtesy of International Culture Collection of Arbuscular Mycorrhizal Fungi, West Virginia University.
The spores of Scleroderma citrinum, more commonly known as the poisonous pigskin puffball, will mature by the time the warted peridium cracks open on its own accord. Photo by David Spahr.
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M YCO R R HI Z AL P L AN E T
NUTRIENT-DENSE HARVEST BIOLOGICAL RESERVES
PHOTOSYNTHESIS EFFICIENCY
FIRST THE SEED
PROTEIN SYNTHESIS
FAT ENERGY
Phytochemical progression kicks into gear with efficient photosynthesis brought about by full availability of trace minerals. Complete protein and lipid synthesis follows from there. Resistance metabolites, kindled in part by mycorrhizal fungi, round out natural plant defenses.
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