quality soil (calidad de suelo)

7/23/2019 QUALITY SOIL (Calidad de Suelo)

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Soil Quality

What is it?How do we measure it?

How do we enhance it?


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5Functions

of Soil

Medium forPlant growth

Recycling

system

Habitat for

Soil organismsWater supplyand purification

Engineering Medium


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DefinitionThe capacity of a soil to:

1. Sustain biological productivity and

diversity2. Maintain environmental quality

3. Promote plant and animal healthSource:Doran & Parkin, 1994)

J.L. Deenik J.L. Deenik


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Brady & Weil, 2004


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Good vs Bad


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Soil Quality Assessment

Look

Feel Smell

Other ?

Physical

Chemical Biological

Descriptive Analytical

J.L. DeenikJ.L. Deenik


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Soil Quality AssessmentIndicator Rationale

Physical

Texture Retention and transport of water and chemicalsDepth of soil and rooting Estimate of productivity potential and erosion

Bulk density and infiltration Potential for leaching, productivity, and erosion

WHC Water retention, transport, and erosivity

Chemical

Total SOM C sequestration, potential fertility, and stability

Active OM Structural stability and food for microbespH Biological and chemical activity threshholds

EC Plant and microbial activity threshholds

Extractable NPK Plant available nutrients, potential for environmental contamination

Biological

Microbial biomass Early warning of management effect on organic matter

Mineralizable N Soil productivity and N supply potentialSpecific respiration Microbial activity per unit microbial biomass

Macroorganisms Potential influence

Doran & Parkin, 1994


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Indicators Sensitivity to

Management

Water content

Respiration

Bulk density pH

NPK

Aggregation

Microbial

biomass Active C

OM content

Soil depth

Slope

Climate Restrictive

layers

Texture

Mineralogy

Rapid Intermediate Permanent


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pH and EC

Bulk density

Depth of soil

Texture

WHC

Extractable NPK

Total SOM

Active OM

N mineralization

Microbial biomass

Microbial diversity

Relatively Simple Difficult


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Soil Quality Monitoring

Intensive sampling

Expensive analysis

Field test kits?

http://www.bentonswcd.org/store/


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Measuring Soil Responses to

Management

Sustainable Management Stability in production and profitability

Protection and enhancement of the natural

resource base Soil responds to

management

Assessment Approaches

J.L. Deenik


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Cultivation and Soil Organic Matter

S

oilOrganicM

atter(mg/ha)

Time After Start of Cultivation (years) Brady & Weil, 2004


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Effects Due to Loss of SOM Increased bulk density

Decreased soil tilth Poor soil structure

Decreased water infiltration

Increased erosion Decreased water holding capacity

Increased susceptibility to drought

Decreased N mineralization potential Decreased microbial biomass/activity

Decreased macrofauna


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Management Effects on Soil Quality

Brady & Weil, 2004


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Examples from Hawaii

TotalN(%)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

SoilOrganicC(%)

0

2

4

6

8

10

12

SoilpH

0

1

2

3

4

5

6

7

Uncultivated

Cultivated

ExtractableP(ppm

)

0

100

200

300

400

500

600

700

Waimea soil:


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Waimea soil:

A

ggregateStability(5

)

0

20

40

60

80

100

120

MBC(ppm)

0

200

400

600

800

1000

1200

Uncultivated

Cultivated

HWEC(ppm)

0

500

1000

1500

2000

2500

NMin

eralizationPotential

(ppm)

0

20

40

60

80

100

120

140

160

180


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HydrudandUstand Ustoll Perox Ustox

HWEC(mgCkg-1)

0

500

1000

1500

2000

2500

3000

3500

Uncultivated

Conventional Cultivation

HydrudandUstand Ustoll Perox Ustox

MBC(mgC

kg-1)

0

500

1000

1500

2000

2500

3000

Hot H2O Extractable C Microbial Biomass C


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N Mineralization Potential Aggregate Stability

Hydrudand Ustand Ustoll Ustox

NMine

ralizationPotential(mgNkg-1)

0

50

100

150

200

250

300

Soil Suborder

Hydrudand Ustand Ustoll Perox

AggregateStability(%)

0

20

40

60

80

100

120

Uncultivated

Conventional Cultivation


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Compost Experiment

Effects of compost on Radish growth and N mineralization

0 11.2 44.8

FreshWeight(g/p

lant)

0

10

20

30

40

50

60

70

%Infection

0

10

20

30

40

50

60

70

Fresh Weight

% Infection

Compost Addition Rate (T/ha)

0 11.2 44.8

MarketableYield(g/plant)

0

10

20

30

40

50

0 11.2 44.8

NMineralizationPotential(mgNH4

+-Nkg-1

-10

-5

0

5

10

15

20

25

a b c

Compost added at 10 and 40 T/acre


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Examples from HawaiiEffects of organic management on a Vertisol, Waianae

MBC(mgCk

g-1)

0

200

400

600

800

1000

1200

1400

1600

HWEC(mgC

kg-1)

0

500

1000

1500

2000

AggregateStability(%)

0

10

20

30

40

50

60

Uncultivated

Organic Management


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Cultivation has had a negative effect on soil quality.

Clear evidence that changes in SOM management arerequired to improve soil quality.

Does improving soil quality directly improve crop

production?


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Fundamental Questions Does improving soil quality

parameters improve crop

quality and production? Do the benefits of usinggreen manure rotationsoutweigh the additional costand labor?

Are animal manures a viableoption?

What role does research playin helping farmers enhance

soil quality

J.L. Deenik


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Building Partnerships

Solution

quality soil (calidad de suelo)

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