Effects of Soil Management on Soil Organisms

Mary Barbercheck Dept. of EntomologyPenn State University

In 1 teaspoon of agricultural soil there are…In 1 teaspoon of agricultural soil there are…

Bacteria 100 million to 1 billion

Fungi 6-9 ft fungal strands put end to end

Protozoa Several thousand flagellates & amoebaOne to several hundred ciliates

Nematodes 10 to 20 bacterial feeders and a few fungal feeders

Arthropods Up to 100

Earthworms 5 or more

Elliot & Coleman. 1988. Ecol. Bull. 39: 23-32

Some Goals of Soil Management

• Manage system for productivity and beneficial processes

• Improvement in abiotic and biotic properties of soil

• Improvement of plant health

• Conservation of beneficial organisms

• Suppression of pests

Crop Rotations

Reduce Pest Habitat

Provide Beneficial Habitat

Know Your Pest

Minimal Pesticide Use

Above-Ground Diversity toFavor Beneficials

Pest and Disease Suppression

Minimal Use of SyntheticPesticides & Fertilizers

Minimize Tillage to Conserve OM

Crop Rotations

Add Organic Matter

Below-Ground Diversity

Healthy Soil

Effects of Agricultural Management on Soil Arthropods

• Densities are much lower than in unmanaged systems, regardless of level and types of inputs

• Favors bacteria over fungi

• Soil arthropods tend to consume fungi

Predators(@ 10% of consumers)

Consumers(@ 10% of producers)

Producers

Energy Pyramid

(After Moldenke, 2002)

Implication of Bacterial Dominance in SoilTypical Ratio B:F >10:1

(After Moldenke, 2002)

Predatory Arthropods (0.0001x)

Predators of BFN (0.001x)

BF Nemas (0.01x)

Protozoa (0.1x)

Bacteria (x)

Predatory Arthropods (0.01x)

FF Invertebrates (0.1x)

Fungi (x)

Bacterial-based Fungal-based

Some Factors Affected by Tillage

• Soil Moisture • Soil Temperature • Range of Temperature

and Moisture Fluctuations

• Surface Residue • Soil Fauna Abundance

and Diversity• Plant Diversity• Favors Bacteria > Fungi

Tillage Effects on Soil Arthropod Abundance & Diversity in Corn

Goldsboro, NC

No Till Conv. Till

No. 2781 1369

Richness 107 88

Simpson .135 .058

Shannon 2.93 3.38

Evenness .396 .566

• Richness: No. of taxa

• Simpson’s: probability that 2 species selected at random will be the same; 0 to 1; diversity decreases as index increases

• Shannon’s: uncertainty in predicting identity of organism chosen at random; equals zero when only 1 species present

• Evenness: 1=all taxa in similar numbers, as approach 0, divergence from evenness, some taxa more dominant

Effects of Tillage on Entomopathogenic Nematodes in Maize

00.20.40.60.8

11.21.4

5/14/

1997

5/21/

1997

5/28/

1997

6/4/1

997

6/11/

1997

6/18/

1997

6/25/

1997

7/2/1

997

7/9/1

997

7/16/

1997

7/23/

1997

7/30/

1997

8/6/1

997

8/13/

1997

8/20/

1997

8/27/

1997

9/3/1

997

Ave

. No.

/Cor

e

Conventional No-till

00.20.40.60.8

11.21.4

5/14/

1997

5/21/

1997

5/28/

1997

6/4/1

997

6/11/

1997

6/18/

1997

6/25/

1997

7/2/1

997

7/9/1

997

7/16/

1997

7/23/

1997

7/30/

1997

8/6/1

997

8/13/

1997

8/20/

1997

8/27/

1997

9/3/1

997

Ave

. No.

/Cor

e

No-till Conventional

S. carpocapsae

S. riobrave

00.20.40.60.8

11.21.4

5/14/

1997

5/21/

1997

5/28/

1997

6/4/1

997

6/11/

1997

6/18/

1997

6/25/

1997

7/2/1

997

7/9/1

997

7/16/

1997

7/23/

1997

7/30/

1997

8/6/1

997

8/13/

1997

8/20/

1997

8/27/

1997

9/3/1

997

Ave

. No.

/Cor

e

Conventional No-till

H. bacteriophora

Millar & Barbercheck, 2002

Effects of Tillage and Cover Crops on Pest & Beneficial Arthropods in Soil

Peachy et al. 2002. Applied Soil Ecology 21: 59-70

0

20

40

60

80

100

Mustard Barley Rye Fallow Oats

Sym

ph

ylla

ns/

m2

Conv. Till Direct Seed Till

0

50

100

150

200

250

300

Mustard Fallow Barley Oats Rye

Pre

dat

ors

/m2

0

0.5

1

1.5

2

2.5

3

CC

Dry

Mat

ter

MT

/ha

Macropredators Pred. Mites CC Dry Matter

Effects of Cover Crop Rye Managementin Reduced Tillage Corn

Clark et al. 1993. J. Entomol. Sci. 28: 404-416

0

5

10

15

20

25

30

Me

an

No

./Plo

t

Predatorsa

ab

bc

c

Effects of Cover Crop Rye Managementin Reduced Tillage Corn

Clark et al. 1993. J. Entomol. Sci. 28: 404-416

0

1

2

3

4

5

6

Mea

n N

um

ber

Roll Paraquat Remove Fallow/Disk

a a

ab

b

a

a a

b

a

b b

b

Effect of Organic & Mineral Fertilizers in AlfalfaFratello et al. 1989. Agric. Ecosyst. Envt. 27: 227-239

0

20

40

60

80

100

120

#/m

2 (

x 1

00

0)

Collembola Mites Other

Effect of Compost Type on Microbial Biomass N and Soil Arthropods

Gunadi et al. 2002. Eur. J. Soil Biol. 38:161-165

0

500

1000

1500

2000

2500

mg

/kg

Paper

Cow Manure

Food Waste

Compost

Microbial Biomass N

1

10

100

1000

10000

Lo

g M

ea

n N

um

be

r

PaperCow M

anureFood W

asteCom

post

Mites Collembola Other

Vermicomposts

72 6 4 Trophic Groups

Systems Experiment 1999-2002Microarthropods Cumulative Average

020

40

60

80

100

120

140

160

180

Ave

. #/C

ore

Pasture BMPCT

Trees BMPNT

OldField

Organic

Other

Coll.

Mites

Barbercheck, unpubl.

Systems Experiment 1999-2002EPN & EPF Cumulative Average

0

2

4

6

8

10

Ave

. #/C

ore

Organic BMP CT Pasture BMP NT Trees Old Field

S.c. H.b. S.g. Fungi

Barbercheck, unpubl.

BMP for Management of Soil Organisms

• Systems effects can arise from very complex direct and indirect interactions

• Minimize compaction• Provide continuous energy

(e.g., cover crops)• Reduce tillage to favor

fungal-based food webs• Provide refuges for mobile

predators• Rotate crops to reduce pest

organisms• Reduce use of biocides

Cosmochthonius (Oribatida)

D. Walter

Web Resources

• Soil Biodiversity Portal www.fao.org/ag/AGL/agll/soilbiod/default.htm

• Soil Biology Primer

http://www.swcs.org

• USDA Soil Quality Institute http://soils.usda.gov/sqi/

• Appropriate Technology Transfer for Rural Areashttp://www.attra.org/

• Earthworms: The agriculturist’s friend http://www.eap.mcgill.ca/publications/eap6.htm

The End

Photo by M. Greenwood