Agroforestry for

Improving Soil

Health and Land

Productivity

Ranjith Udawatta

The world would still

need 974 more calories

per person each day in

2050 even if all the food

produced in 2009 were

distributed to all people

in 2050

A huge calory need and uneven food distribution

Challenge Produce more

and high quality food

Middle class expansion (next 20 yrs)

73% more meat by 20502 billion in 2010 --- 4.9 billion in 2030

Brookings Institute

Meat consumption, Soil and Water

3

6

9

1950 60 70 80 90 00

Oz/day/person

3 billion People * 4 oz/day

750,000,000 lb meat/day

~1500 lb/animal

500,000 animals/day

Water need for 1lb

Beef 1850, chicken 519, bread 193 gal

USDA/Economic Research Service, www.ers.usda.gov

Challenge

Land Limitation/Productivity

Cynthia Nickerson, Robert Ebel, Allison Borchers, and Fernando Carriazo. 2011. Major Uses of

Land in the United States, 2007. USDA. Economic Information Bulletin 89

41 million ac Ag

land in US

1982-2007

7% more by 2030

1200 m2

0.3 ac

Actual soil erosion

rates are greater than

the upper limit of

tolerable soil erosion.

Erosion from Midwest cropland is

up to 12 times higher than the

federal government’s estimates.

Economists put the cost of soil

erosion between $60 and $100

billion per year.

Problems

Cox et al. 2011 Losing Ground. Environmental Working Group.

Actual soil erosion rates for tilled, arable land in

Europe are, on average, 3 to 40 times greater

than the upper limit of tolerable soil erosion.

Types of Soil Degradation FAO, 2015

(Global Assessment of Soil Degradation (GLASOD) evaluate 13 types of soil degradation)

1. Water erosion (topsoil loss and mass movement, including rill and gully formation)

2. Wind erosion (topsoil loss, terrain deformation– primarily dune activity)

3. Overblowing (surface burial from aeolian deposition)

4. Loss of nutrients

5. Loss of organic matter

6. Salinization

7. Acidification

8. Pollution

9. Compaction

10. Physical degradation

11. Waterlogging

12. Subsidence of organic soils

13. Water Scarcity

Water Quality

Water Body Total size Assessed(% of total)

Impaired(% of assessed)

Rivers 3,533,205 miles 16% 44%

Lakes 41.7 million acres 39% 64%

Estuaries 87,791 square miles 29% 30%

USEPA, 2013

Soil Erosion and Productivity

Al-Kaisi 2001. Soil erosion and crop productivity:

topsoil thickness

13%

30%

Stocking 2003. Tropical soils and

food security: The next 50 years.

Science, 302:1356-1359.

Problems

Agricultural output gains have shifted from input intensification in

1960s -1980s to efficiency gains in recent years

(rate of output growth, % per year)

WRR, 2013-14 World Resources Institute

Need to pay more attention on increase of efficiency

Efficiency Gains:

Selection of correct cultivar

Site specific management (land preparation,

efficient planting/seeding, fertilization,

irrigation, chemical application,… harvest)

Use of efficient equipment

Provide required input at the right time

Incorporation of weather data for management

decision

AGROFORESTRY

“Intensive land-use management

that Optimizes the benefits

(physical, biological, ecological,

economic, social) from biophysical

Interactions created when trees

and/or shrubs are Intentionally

Integrated combined with crops

and/or livestock”Gold and Garrett, 2009.

Paired watershed at Greenley Center Grazed Pasture watersheds at HARC

Google image 2014Google image 2015

Approximate study site location in Missouri and 0.5 m interval contour lines on

watersheds. Gray bands represent location of contour grass buffers on contour

strip watershed, agroforestry buffers on agroforestry watershed and grass

waterways on all three watersheds.

West Center East

1991-1997

2002

2005

2007

1999

2012

Soil Erosion and Nutrient Loss

Udawatta et al. 2002 and 2011. J Environ. Qual. 31:1214-1225 40:800-806.

Runoff

m3ha-1

39

43

48

1

3

5 1

3

5

5

Map of United

States

Profile view of well installation at (HARC)

Well 5 (3.6 m)

Well 1 (12.2 m)

Well 3 (10.7 m)

Ground water flow direction

Buffer

zone

20

LAKE

0

1

2

3

4

5

Co

nce

ntr

atio

n (

mg

L-1

)

NO3-N HARC 1-1

0

1

2

3

4

5

3 7 11 15 19 23 27 31 35 39 43 47 51

Co

nce

ntr

atio

n (

mg

L-1

)

Week of year

NO3-N HARC 1-5

Nitrate and Total NitrogenHARC

1-1

HARC

1-5

HARC

1-3

21

0

2

4

6TN HARC 1-1

0

2

4

6

3 10 17 24 31 38 45 52

Week of year

TN HARC 1-5

22

Well

locationsAverage SD SE

NO3-N

(mg L-1)

TN

(mg L-1)

NO3-N

(mg L-1)

TN

(mg L-1)

NO3-N

(mg L-1)

TN

(mg L-1)

Summit 2.72 3.35 1.11 1.51 0.10 0.19

Mid slope 2.53 2.99 1.25 1.15 0.15 0.26

Foot slope -

with

agroforestry

buffer

0.03 0.10 0.026 0.17 0.003 0.025

Foot slope -

with grass

buffer0.09 0.30 0.052 0.31 0.007 0.046

HARC

1

HARC

5

HARC

3

HARC 1

HARC

5

HARC

3

HARC

1-1

HARC

1-5

HARC

1-3

HARC

2-1HARC

2-5

HARC

2-3

2004 Monthly Precipitation and

Cropping Period

Figure 5.

0

75

150

225

J F M A M J J A S O N D

Pre

cip

itation (

mm

)

2004Corn

5/22/04

Long-term

precipitation

670 mm

(944mm)

Runoff Control

After NRCS, 2002

Reported Effectiveness of Buffer Zone Width for Sediment Reduction in the USA (Earlier studies)

Runoff reduction varies with buffer width and ranged between 40 and 100%

Wider the better

Liu et al., 2008. Major factors influencing the efficacy of

vegetated buffers on sediment trapping: a review and

analysis. J. Environ. Qual. 37, 1667-1674

Buffer width and water quality

Mayer et al., 2005. Riparian Buffer Width, Vegetative

Cover, and Nitrogen Removal Effectiveness: A Review

of Current Science and Regulations EPA/600/R-

05/118. October 2005

Riparian Forest Buffer

Planned combinations of trees, shrubs, grasses, forbs & bioengineered structures designed to mitigate the impact of land-use on a stream or lake.

4 year old RFB

Native Grass

Shrubs Trees

Four-zone riparian buffer and environmental benefits and associated

buffer widths. Different widths for different pollutants.

Naiman, R., H. Decamps, and M. McClain. Riparia. 2005, Elsevier

Image taken March 23, 1992

Image taken February 23, 1995

Image taken August 13, 2009

APEX Model Assessment of

Environmental Benefits of

Agroforestry/Grass Buffers

MODEL SIMULATIONAPEX

TopographyManagement

Soil Data

0

400

800

1200

1600

1991 1993 1995 1997 1999 2001 2003 2005

Precipitation

Measured

Data

Simulations Crop and buffer

areas were

simulated as

separate subareas.

Model calibration:

using agroforestry

buffer (grass and

tree) watershed

data (1998-2008, 43

events).

Model validation:

using grass buffer

watershed data.

Scenario analysis% area under buffers and placement

• 20% area in upland contour buffers

• 10% backslope 10% toeslope flat shape buffer

• 10% backslope 10% toeslope v-shape buffer

• 20% toeslope flat shape buffer

• 20% toeslope v-shape buffer

• 20% backslope buffer

Runoff Simulations

0

50

100

1500

3/2

9/9

80

4/0

8/9

80

4/1

5/9

80

4/2

8/9

80

5/0

7/9

80

5/1

2/9

80

5/2

3/9

80

6/0

8/9

80

6/1

5/9

80

6/1

8/9

80

6/2

3/9

80

6/2

9/9

81

0/0

5/9

81

0/1

7/9

81

1/1

0/9

81

2/0

6/9

80

4/1

6/9

90

5/0

5/9

90

5/1

7/9

90

4/2

2/0

10

5/0

6/0

10

5/1

3/0

10

6/0

1/0

10

6/0

6/0

10

5/0

1/0

20

5/0

9/0

20

5/2

5/0

20

6/1

3/0

20

4/3

0/0

30

5/1

0/0

30

9/1

8/0

30

9/2

1/0

30

4/2

0/0

40

5/3

1/0

40

6/1

5/0

40

8/2

8/0

40

6/0

5/0

50

6/0

8/0

50

5/0

6/0

70

4/2

5/0

80

5/1

1/0

80

6/1

8/0

8Ru

no

ff (

mm

)

Storm event

Mearsured runoff Simulated runoff

0

50

100

150

03

/29

/98

04

/08

/98

04

/15

/98

04

/28

/98

05

/07

/98

05

/12

/98

05

/23

/98

06

/08

/98

06

/15

/98

06

/18

/98

06

/23

/98

06

/29

/98

10

/05

/98

10

/17

/98

11

/10

/98

12

/06

/98

04

/16

/99

05

/05

/99

05

/17

/99

04

/22

/01

05

/06

/01

05

/13

/01

06

/01

/01

06

/06

/01

05

/01

/02

05

/09

/02

05

/25

/02

06

/13

/02

04

/30

/03

05

/10

/03

09

/18

/03

09

/21

/03

04

/20

/04

05

/31

/04

06

/15

/04

08

/28

/04

06

/05

/05

06

/08

/05

05

/06

/07

04

/25

/08

05

/11

/08

06

/18

/08

Ru

no

ff (

mm

)

Storm event

Model calibration by agroforestry buffer watershed

Model validation by grass buffer watershed

Performance indicatorsModel output

Model Coefficients

Calibration Validation

Agroforestry buffer WS

Grass buffer WS

Event Runoff

r2 0.82 0.77

NSC 0.80 0.73

Pbias 2.17 7.72

Event sediment

r2 0.39 0.18

NSC 0.28 0.07

Pbias 7.90 -15.59

Event total P

r2 0.61 0.69

NSC 0.55 0.57

Pbias -10.15 15.39

30 year

simulation

Scenario

% Annual Average Reductions

Runoff Sediment TP

AGF CGS AGF CGS AGF CGS

With upland buffers 20 10 58 54 24 20

10% flat toeslope

10% Back slope buffers 21 11 77 76 23 19

10% v-shape toeslope

10% Back slope buffers 22 10 76 75 26 21

20% flat toeslope buffers 16 6 62 61 19 15

20% v-shape toeslope buffers 20 10 63 63 22 18

20% backslope buffers 21 10 56 54 23 19

• APEX model quantified the benefits of

agroforestry and grass buffers and

their different placement shapes and

proportions.

• Buffers reduce 6-22% runoff, 54-77%

sediment, 15-26% TP.

• 10% back-slope 10% toe slope buffers

reduced highest amount of sediments

than other treatments.

• Toeslope buffers were better for

sediment reductions than the

backslope buffers.

Soil Physical PropertiesCores:

0-10

10-20

20-30

30-40

40-50 cm

Bulk density and saturated hydraulic conductivity (Ksat) for row

crop, grass buffer, and agroforestry buffer

treatments by soil depth.

0

10

20

30

40

50

1.0 1.2 1.4 1.6

Bulk Density (g cm-3)

De

pth

(c

m)

Crop

Grass

AGF

0

10

20

30

40

50

0 10 1000

Ksat (mm hr-1)

Dep

th (

cm

)

Crop

Grass

AGF

Seobi et al 2005. Agroforestry influence on soil hydraulic properties. Soil Sci Soc Am J 69:893-901.

Soil Pores and Agroforestry

Pore scale (x-ray CT, micro-computed tomography)

Gantzer and Anderson, 2006

Udawatta and Anderson, 2008. Geoderma 145:381-389

Water Stable Aggregate

0

10

20

30

40

Crop Grass Agroforestry Grass

Waterway

Wat

er S

table

Aggre

gat

es (

%)

Udawatta et al., 2008 Applied Soil Ecology 39:153-160

0

10

20

30

40

1-Oct 6-Oct 11-Oct 16-Oct 21-Oct 26-Oct 31-Oct

Date

Pre

cip

itati

on

(m

m)

Daily Precipitation During

October 2004 Recharge Period166 mm

Soil Water Storage

Campbell TDR soil

moisture sensors

were installed on

two transects

Study Design

Buffer

Pin oak

5 cm

10 cm

20 cm

40 cm

Senor depths

Data logger

Sensor locations

Soil Water Recharge (5 and 10 cm depths)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

Oct 7,

6:00

Oct 8,

6:00

Oct 9,

6:00

Oct

10,

6:00

Oct

11,

6:00

Oct

12,

6:00

Oct

13,

6:00

Oct

14,

6:00

Oct

15,

6:00

Oct

16,

6:00

Oct

17,

6:00

Oct

18,

6:00

Oct

19,

6:00

Oct

20,

6:00

Oct

21,

6:00

Oct

22,

6:00

Date and Time

VWC

(cm

cm

-3)

Corn

Tree5 cm Depth

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

Oct 7,

6:00

Oct 8,

6:00

Oct 9,

6:00

Oct

10,

6:00

Oct

11,

6:00

Oct

12,

6:00

Oct

13,

6:00

Oct

14,

6:00

Oct

15,

6:00

Oct

16,

6:00

Oct

17,

6:00

Oct

18,

6:00

Oct

19,

6:00

Oct

20,

6:00

Oct

21,

6:00

Oct

22,

6:00

Date and Time

VWC

(cm

cm

-3)

Corn

Tree10 cm Depth

0

10

20

30

40

1-Oct 6-Oct 11-Oct 16-Oct 21-Oct 26-Oct 31-Oct

Date

Pre

cip

itati

on

(m

m)

Soil Water Recharge (20 and 40 cm depths)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

Oct 7,

6:00

Oct 8,

6:00

Oct 9,

6:00

Oct 10,

6:00

Oct 11,

6:00

Oct 12,

6:00

Oct 13,

6:00

Oct 14,

6:00

Oct 15,

6:00

Oct 16,

6:00

Oct 17,

6:00

Oct 18,

6:00

Oct 19,

6:00

Oct 20,

6:00

Oct 21,

6:00

Oct 22,

6:00

Date and Time

VW

C (c

m c

m-3

)

Corn

Tree20 cm Depth

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

Oct 7,

6:00

Oct 8,

6:00

Oct 9,

6:00

Oct

10,

6:00

Oct

11,

6:00

Oct

12,

6:00

Oct

13,

6:00

Oct

14,

6:00

Oct

15,

6:00

Oct

16,

6:00

Oct

17,

6:00

Oct

18,

6:00

Oct

19,

6:00

Oct

20,

6:00

Oct

21,

6:00

Oct

22,

6:00

Date and Time

VW

C (c

m c

m-3

)

Corn

Tree

40 cm Depth

0

1

2

3

Crop Grass Agroforestry Grass

waterways

So

il C

arb

on

(%

)

0.00

0.05

0.10

0.15

0.20

0.25

So

il N

itro

gen

(%

)

Carbon Nitrogen

Soil Carbon and Nitrogen

Udawatta et al., 2008. Agriculture, Ecosystems and Environment 131:98-104

Carbon SequestrationAGROFORESTRY is recognized as an activity

under Afforestation and Reforestation activities

that have been approved as a GHG mitigation

strategy under the Kyoto Protocol.

Reduction of 1 Pg from soil = 0.47 ppm CO2 to atmosphere

(Lal, 2001).

0

10

20

30

40

50

60

70

Semiarid Subhumid Humid Temperate

Mg

C h

a-1

Average C storage by Agroforestry Practices

Montagnini and Nair 2004

Carbon Sequestration

Agroforestry systems have a greater

Potential to sequester C than pasture

or cropping systems (Sanchez, 2000;

Sharrow and Ismail, 2004; Kirkby and Potvin, 2007).

Alley cropping systems sequester 142 Tg C yr-1.

(Lal et al., 1999)

C Seq capacity in agroforestry varies from 0.29 to 15.21

Mg C ha-1 yr-1 (landuse, soil, mgt, spp, age, climate,

stand age, aggregates; Nair et al 2009)

Carbon Sequestration:

Corn Soybean Grass

Tree Roots1. Depth2. Volume3. Carbon form (recalcitrant)4. Root exudates (leaching)5. Root Turnover (33% NPP fine root)

6. Associated microbial communities C, exudates, turnover

More

above- and

below-

ground C

in tree

areas

than grass

and crop

areasTrees and perennial vegetation within agriculture help improve SQ, greater C accumulation diverse soil communities and activities Tufekoioglu et al 2003

Fine root

biomass

of trees

and

grasses

were

greater

than

annual

crops

Tufekoioglu et al 1999

Above and belowground biomass and C of 2, 8,

12, and 60 year riparian stand in South Carolina

Giese et al., 2003

Soil C% 4.2 4.7 4 11.4

Distance from trees and by time Alleycropping

Thevathasan and Gordon, 1997

Grazing system: root biomass and root C

Kumar et al., 2010

Above and belowground biomass and C for

shelterbelt species

Kort and Turnock, 1999

Nair, P.K.R., B.M. Kumar, and V.D. Nair. 2009. Agroforestry as a strategy for carbon

sequestration. J Plant Nutrition and Soil Science. 172. 10-23.

164 published manuscripts have been used.

Lack of data and differencesin estimationmethodsaffectedfinaloutcome

A comparison of C sequestration potential for

different management practices

Udawatta, R.P. and S. Jose, 2012. Agroforestry strategies to sequester carbon in temperate North America. Agroforestry Systems 86:225-242.

Riparian buffers

Alley Cropping

Windbreaks

and Silvopasture could sequester

548.4 Tg C year-1

Current US CO2 emission is 6870

million metric tons or 1874 Tg C

Agroforestry can offset current C

emission by 34%

Udawatta, R.P. And S. Jose. 2011. Carbon sequestration potential of agroforestry

practices in temperate North America. 17-42. Advances in Agroforestry. Springer

Organic Matter on Available Water Capacity

Silt loam

OM increase from 1% to 4.5%

AWC doubles!

5.7% 22.9% (% by Vol.)

Data from Soil Survey Investigation Reports

(surface horizons only)

- Sands: FL (n = 20)

- Silt loams: IA, WI, MN, KS (n = 18)

- Silty clay loams: IA, WI, MN, KS (n = 21)

Sands AWC = 3.8 + 2.2 (OM)

r2 = 0.79

Silt loams AWC = 9.2 + 3.7(OM)

r2 = 0.58

Silty clay loams AWC = 6.3 + 2.8 (OM)

r2 = 0.76

Hudson, B. D. 1994. Soil organic matter and available

water capacity. J. Soil Water Conserv. 49(2):189-194.

Soil Enzymes

0

20

40

60

80

100

120

p-n

itro

ple

ny

l p

rod

uct

ion

(μg

/ g

-1d

ry s

oil

h-1

)

0

25

50

75

100

125

p-n

itro

ph

eny

l

pro

du

ctio

n

(μg/

g-1

dry

soil

h-1

)

0

1

2

Crop Grass Agroforestry Grass Waterway

Flo

ure

cein

pro

du

ctio

n

(μg

g-1

dry

so

il h

-1)

0

2

4

6

8

Crop Grass Agroforestry Grass Waterway

Tri

phen

ylf

orm

azan

pro

duct

ion

(μg/

g-1

dry

soil h

-1)

β-glucosidase Glucosaminadase

Dehydrogenase FDA

c b a a

c b a ab b b a

c a b b

Perennial

Vegetation

buffers have

increased

microbial

diversity and

enzyme

activities.

Udawatta et al., 2008. Agriculture, Ecosystems and Environment 131:98-104

21-year old

pecan alley

cropping.

Greater

Enzyme

activity

diversity

in tree rows

than middle

of tree rows

in crop allies.

Mungai, N.W., P.P. Motavalli, R.J. Kremer, and K.A Nelson. 2005. Spatial variation of soil enzyme activities and

microbial functional diversity in temperate alley cropping systems. Biol Fertil Soils 42:129-136.

Soil Enzymes

Lin, C.H., K.W., Goyne, R.J. Kremer, R.N. Lerch, and H.E. Garrett. 2010. Dissipation of sulfamethazine and tetracycline in the root zone of grass and tree species. Journal of Environmental Quality 39:1269-1278

Rhizodegradation of antibiotics

Lin, C.-H., R.N. Lerch, K.W. Goyne, and H.E. Garrett. 2011. Reducing herbicides and veterinary antibiotic losses from agroecosystems using vegetative buffers. J. Environ. Qual. 40:791-799.

Lin, C.-H., R.N. Lerch, K.W. Goyne, and H.E. Garrett. 2011. Reducing herbicides and veterinary antibiotic losses from agroecosystems using vegetative buffers. J. Environ. Qual. 40:791-799.

Chu, B., K.W Goyne, S.H. Anderson, C.H. Lin, and R.P. Udawatta 2010. Veterinary antibiotic sorption to agroforestry buffer, grass buffer, and cropland soils. Agroforestry Systems 79:67-80

Soils under

agroforestry and

grass buffer

exhibit enhanced

sorption of

oxytetracycline

and sulfadimethoxine relative

to cropland.

This suggests that the sorptive

capabilities of buffer soils help

reduce the loss of veterinary

antibiotics from

agroecosystems.

Maintaining an efficient nutrient

cycling improve soil quality and

provides other services

including improved water

quality, food security and

ecosystem services

Lal 2010 Bioscience 60:708-721

Soil Heat Transfer

Adhikari, P., R.P. Udawatta, S.H. Anderson, and C.J. Gantzer. 2014. Soil thermal properties under prairies, conservation buffers,

and corn/soybean land use systems. Soil Science Society of America Journal 78:1977-1986.

Thermal conductivity Thermal diffusivity

Soil Heat Transfer

Adhikari, P., R.P. Udawatta, S.H. Anderson, and C.J. Gantzer. 2014. Soil thermal properties under prairies, conservation buffers,

and corn/soybean land use systems. Soil Science Society of America Journal 78:1977-1986.

Volumetric heat capacity

Significantly lower thermal

conductivity and diffusivity

and higher volumetric heat

capacity were observed

under TP, PF, AGF, and

GB compared with the

COS land use system.

Similarly, these prairies

and conservation buffer

land use systems had

higher SOC and lower BD

than the COS at the 0- to

10- and 10- to 20-cm

depths.

• New Varieties

• Fertilizer

• Pesticide

• Machinery

• Technology

Management

• Physical

• Chemical

• Biological

• Conservation

Soil Quality

• Supply

• Market

• Loans/banks

• Land Reform Policy

Ecosystem

Services

Increased

AG

Production

Food

Security

Pollinators and AgroforestryApproximately 80% of all flowering plant species

are pollinated by animals, mostly insects

Pollinators are needed for 35% of the world's crop

production

Increase the output of 87 of the leading food crops

worldwide

Pollinators are critical to crop production, provides

an essential ecosystem service

Multi spp buffers with native and other plants with

year round flowering

Silvopasture Cattel Weight and IncomeSide-by-side

2 years

Traditional “open” pastures with limited shade

Integrated silvopasture x open pasture where 25% of

the pasture area is silvopasture and 75% of the

pasture area is a traditional open pasture

Cows in the Integrated system

Lost approximately 10%

less weight over winter

Had less stress at calving

Weaned heavier calves

Treatment Cow BW

loss over

winter

(lbs)

Calving

Difficulty

%

Calf

Weaning

Weight

(lbs)

Traditional 231 17 595

Integrated 205 4 650

p value 0.02 0.04 0.01

$ value $16.89 - $25.74

2009 Study $43

Current monitory value is ~$52 per cow calf pair

Silvopasture Profitable Agroforestry

Kallenbach, R. 2009. Agroforestry Comes of Age, Proc North Ame. Agroforestry Conference.

Forage growth begins earlier in the spring and continues later into the fall

Forage yields are higher in the heat of summer

Better quality forage

Optimal distribution (reduce hay need and $)

Reduced Heat stress and better weight gain

$43 (2009) per cow calf pair

Ginseng

Profitable

Agroforestry

At the current

prices, a half

acre could

produce

$100,000 worth

of seeds and

roots over a six

year period, or

over $16,000

per year.

Shiitake

Mushroom

Profitable

Agroforestry

Steve Gabriel, 2015. http://smallfarms.cornell.edu/2015/01/12/mushrooms/

The Center for Agroforestry