NS 435Unit 5:Effect of Soil Composition

on Nutrition & Health

“The soil is the great connector of our lives, the source and destination of all.” Wendell Berry

Nanna Cross, PhD, RD, LDN

Reminders

Unit 3 Project Questions Unit 6 Project Unit 9 Project Tour of USDA website

What are the Four Main Components of Soil?

Minerals 45% Air 25% Water 25% Organic Matter 2 – 5%

WHAT ARE FIVE FUNCTIONS OF SOIL?

What Soil Does

Regulates water Soil helps control where rain,

snowmelt, and irrigation water goes. Water and dissolved solutes flow over

the land or into and through the soil.

Source: Soil Quality Concepts. USDA. Natural Resources Conservation Service.

What Soil Does

Sustains plant and animal life The diversity and productivity of living

things depends on soil.

Source: Soil Quality Concepts. USDA. Natural Resources Conservation Service.

What Soil Does

Filters potential pollutants Minerals & microbes in soil are

responsible for filtering, buffering, degrading, immobilizing, & detoxifying organic & inorganic materials, including industrial & municipal by-products & atmospheric deposits.

Source: Soil Quality Concepts. USDA. Natural Resources Conservation Service.

What Soil Does

Cycles nutrients Carbon, nitrogen, phosphorus, and

many other nutrients are stored, transformed, and cycled through soil.

Source: Soil Quality Concepts. USDA. Natural Resources Conservation Service.

What Soil Does

Supports structures Buildings need stable soil for support. Archeological treasures associated

with human habitation are protected in soils.

Source: Soil Quality Concepts. USDA. Natural Resources Conservation Service.

What are the Characteristics of Good

Soil?

Drains well Soaks up heavy rain with little

runoff Stores moisture for periods of

drought

What are the Characteristics of Good

Soil? Resists erosion & nutrient loss Supports soil organisms Produces healthy, high quality

crops

Soil Fertility: A Delicate Balanceis Essential

pH “best” pH for

fruits/veggies = 6.0 to 7.0

Soil nutrients nitrogen calcium magnesium phosphorus potassium sulfur boron, iron, zinc

What are the Resources for Soil Testing in Your Community?

Soil testing to keep soil “healthy” &/or fertile

Soil testing for toxins (lead)

Managing Soil Organic Matter

Source: Soil Organic Matter. USDA. Natural Resources Conservation Service.

Explain These Terms Related to Soil Management

Agricultural production Cover crops Reduced tillage Prescribed grazing Manure management High biomass rotation

Landscaping Xeriscaping

Sustainable Agriculture

Do these Practices Sustain Soil?

Tillage speeds up decomposition

Excess nitrogen (fertilizer/manure) speeds up decomposition

Insufficient nitrogen (fertilizer) slows down decomposition & starves

plants

Management of Water Runoff

What’s Your Soil Problem?

Impact of climate change on soil drought floodingWind/water erosion with loss of water top soil nutrientsLeaching- r/t quality & type of soil

Soil Erosion

Dust Bowl Days

Soil Erosion

How Does Soil AffectHuman Health?

Industrial pollution Lead, arsenic Dioxin, PCBs

Agricultural pollution Animal waste (manure) Pesticides Fertilizers Herbicides

How Does Soil Affect Human Health?

Soil pollution can adversely affect human health Infectious diseases: parasites Toxins/pollutants

Nutrient quality of soil impacts absence/presence of disease states protein calorie malnutrition

How Does Soil AffectHuman Nutrition?

Affects nutritional status via: Deficiencies/toxicities may be

related to nutrient quality of the soil nitrogen depleted soil nitrogen leakage more likely in sandy

soil

How Does Soil AffectHuman Nutrition?

Affects nutritional status via: Soil provides nutrients

minerals nitrogen

Different types of soil have varied nutrients clay holds more nutrients than sand

The Living Soil

Earthworms Bacteria Arthropods Fungi Actinomycetes Nematodes Algae

Weights of Soil Organisms in Top 7 Inches of Fertile Soil

Organism Pounds of Live Weight/Acre

Bacteria 1000

Actinomycetes 1000

Molds 2000

Algae 100

Protozoa 200

Nematodes 50

Insects 100

Worms 1000

Plant Roots 2000

What can I do to be a Steward of the Soil?

Compositing Xeriscaping Mulching Collecting rain (rain barrel) Choose native plants Choose pest resistant plants

References

Photos courtesy of USDA, NACD, and Ron Francis

NRCS/USDA. (n.d.) Soil quality/soil health concepts. Retrieved from

http://soils.usda.gov/sqi/concepts/concepts.html Sullivan, P. (2004) Sustainable Soils

Management. Soils Systems Guide. Pgs 1-31. Retrieved from: *no longer free access

http://attra.ncat.org/attra-pub/PDF/soilmgmt.pdf

Tour of USDA Website http://www.usda.gov/wps/portal/usda/usdahom

e Food and Nutrition

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