# Presentation: 476921

## (SQ – 1) Soil Biology Primer

**Components of ****Soil Organic Matter**

- Photos taken from the NRCS Soil Quality Institute website
- Source: Soil Biology Primer

**Notes:**
Copyright restrictions for photos in this presentation:
The text and non-photo graphics are products of the USDA Natural Resources Conservation Service (NRCS). They may be used freely. Credit the USDA Natural Resources Conservation Service.

Some photos are from the NRCS or ARS and may be used freely. Credit the USDA Natural Resources Conservation Service or USDA Agricultural Resource Service as appropriate.

Photos from non-government sources were lent to the NRCS for use in the Soil Biology Primer and this slide set. Other uses may be restricted. Contact original source for permission.

Credit (for this slide only):
Courtesy of USDA Natural Resources Conservation Service.

File names (for this slide only):
MITEgray
Handlowres
amoeba

## Soil Biology and the Landscape

**Rhizosphere**

**Notes:**
When you look across a landscape, imagine the microscale habitats and complex ecosystem under the surface.

Credits: 
(drawing) S. Rose and E.T. Elliott; 
(photo) Arlene J. Tugel, USDA-NRCS
File names: Rose, grass

## Typical Numbers of Soil Organisms in Healthy Ecosystems

|  | Ag Land | Prairie  | Forest |
| --- | --- | --- | --- |
|  | Organisms per gram (teaspoon) of soil |  |  |
| Bacteria | 100 mil. -1 bil. | 100 mil. -1 bil. | 100 mil. -1 bil. |
| Fungi | Several yards | 10s – 100’s of yds | 1-40 miles 
(in conifers) |
| Protozoa | 1000’s | 1000’s | 100,000’s |
| Nematodes | 10-20 | 10’s – 100’s | 100’s |
|  | Organisms per square foot |  |  |
| Arthropods | < 100 | 500-2000 | 10,000-25,000 |
| Earthworms | 5-30 | 10-50 | 10-50
(0 in conifers) |

**Notes:**
Each type of ecosystem has a characteristic food web structure.
Credit: USDA Natural Resources Conservation Service

## Microbial Biomass with Depth

**Seasonal Microbial **
**Activity**

**Notes:**
File name: A-6.  445KB  (Also depth.jpg at 170K)
Image courtesy of USDA-NRCS

## Complexity of the Soil Food Web in Several Ecosystems

- Organic nutrients are stored in soil organisms and organic matter.

**Mineralization **
**and Immobilization**

**Notes:**
File name: Funct.jpg 382K

Image credit: USDA-NRCS

## Bacteria with fluorescent stain for counting 

**Notes:**
Credit for both photos: Serita Frey, The Ohio State University
File names: SF4 bact.jpg, SF1 bact.jpg

## Nitrogen-fixing Bacteria

- Nodules formed where *Rhizobium* bacteria infected soybean roots.

**Actinomycetes **
**(decomposers)**

- Bacterial cells that grow like fungal hyphae

**Notes:**
File name: Nods on Beans.jpg 277K  (Also C-2 at 580K shows whole box.)

Photo credit: Stephen Temple, New Mexico State University. 

## FUNGI

**- Decompose carbon compounds**
**- Improve OM accumulation**
**- Retain nutrients in the soil**
**- Bind soil particles**
**- Food for the rest of the food web**
**- Mycorrhizal fungi**
**- Compete with plant pathogens**

**Mushrooms:The fruiting **
**body of some fungi**

**Notes:**
Credit: Serita Frey, The Ohio State University
File name: SF6

## Mycorrhizae

- Tree root

- Mycorrhizal structure

- Fungal hyphae

**Notes:**
Photo credit: Randy Molina, Oregon State University, Corvallis.
File name: M4 Fungi LR.jpg, 328K

## Ectomycorrhizae

**Mycorrhizal Fungi**

**Arbuscular ****Mycorrhizae (AM)**

**Notes:**
Photo Credit: USDA, Forest Service, PNW Research Station, Corvallis, Oregon.
File name: Ectomy~1

## Springtails (fungal feeders)

- Abundant in many soils.
- Feed on some disease-causing fungi.
- Jump by slamming their tail down.

**Notes:**
Photo credits:
(light microscope) Andrew R. Moldenke, Oregon State University, Corvallis.
File names:
(light microscope) M7B

## PROTOZOA

- Flagellate

**Ciliate**

**Amoebae**

**Soil-Dwelling ****“Vampires”**
**(amoebae that eat fungi)**

**Notes:**
File name: Testate amoeba LR.jpg,  179K
Credit: Elaine R. Ingham, Oregon State University, Corvallis

## NEMATODES

- Bacterial-Feeding
- Nematode

- Fungal-Feeding
- Nematode

**Predatory **
**Nematode**

- Lesion-Feeding
- Nematode

- Root-Feeding
- Nematode

**Notes:**
File name: large todes LR.jpg, 262K
Credit: Elaine R. Ingham, Oregon State University, Corvallis.

## Herbivores

- (Symphylan)

**Notes:**
Photo credits:
(symphylan) Ken Gray Collection, Department  of Entomology, Oregon State University, Corvallis.

File names:
(symphylan) M11 Symphylan

## FOOD WEB & SOIL HEALTH

- Mites shredding a leaf

**Mites and Biodiversity**

- (Predatory Mite)

**Notes:**
Many effects of soil organisms are a result of the interactions among organisms, rather than the actions of individual species.
This implies that managing for a healthy food web is not primarily a matter of inoculating with key species, but of creating the right environmental conditions to support a diverse community of species.

Photo: A predacious mite (Labidostomatidae) feeds on a springtail.
Photo credit: Roy A. Norton, State University of New York at Syracuse.
File names: predacious mite, M10 Mite & springtail

## Shredders:millipedes

**Notes:**
The millipede on the light background is Orthoporus ornatus.

Photo Credits:
(beetle) A. Beaumont, Lowestoft
(millipede, brown background) No. 41 from Soil Microbiology and Biochemistry Slide Set. 1976. J.P. Martin, et al., eds. SSSA, Madison, WI
(millipede, light background) David B. Richman, New Mexico State University.

File names:
(beetle) INSECT~3
(millipede) SSSA41
(millipede, light background) Orthopor  472K

## Predators:Pseudoscorpions

- Rugose Harvester Ants

- Centipedes

- Wolf Spider

**Notes:**
With green background is a Homosphyronid.

Credits:
(green) David B. Richman, New Mexico State University, Las Cruces.

File names:
(green) Pseudo4  (461K)
(yellow body) Pseudoscorpion.jpg 

## EARTHWORMS

**Earthworm burrow**

**Notes:**
Photo credit:  Clive A. Edwards, The Ohio State University, Columbus.
File name: CD1 ew bunch

## Vertical burrows

**Earthworms ****bury litter**

**Midden pile**

**Burrow opening**

**Earthworm casts**

**Notes:**
Photo and image credit: North Appalachian Experimental Watershed, USDA-Agricultural Research Service, Coshocton, Ohio

**Notes:**
Learning about the relationship between soil management and the soil food web requires the observations and field trials of land managers along with formal research.
Credit: Arlene Tugel, USDA-NRCS Soil Quality Institute