Intro to soil health concepts

1. Soil Health ↔ Soil Function
Kitty O’Neil, Ph.D.
Cornell Cooperative Extension, NNY
Northern NY Field Crops Team

2. Soil Health ↔ Soil Function
• At the end of the hour…
– Understand the functions of soil and their
dependence on soil composition and
structure
– Explain to someone what soil is made of ,
how it’s organized and how it behaves
– Think of some ideas how you might
preserve or improve your soil health
Northern NY Field Crops Team

3. Why do we care about soil?
?
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4. Why do we care about soil?
• Soil resources were and are a central factor
in shaping human history and development.
• Survival of humans and animals is dependent
on light, water, air and soil.
• Civilizations have crashed as a result of
degraded soil.
• Good, productive soil is a basic human need.
Northern NY Field Crops Team

5. Why do we care about soil?
• “Man—despite his artistic pretensions,
his sophistication, and his many
accomplishments—owes his existence to
a six-inch layer of topsoil and the fact
that it rains.”
- Author unknown
Northern NY Field Crops Team

6. What does soil DO?
OK, so soil is important.
Why? What does soil actually DO?
?
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7. What does soil DO?
1. Soil serves as a natural medium for the
growth of plants,
2. regulates and purifies water,
3. recycles organic wastes and nutrients,
4. provides habitat for soil organisms, and
5. serves as physical support for building and
construction.
= Soil functions
Northern NY Field Crops Team

8. What does soil DO?
1. Soil serves as a natural medium for the
growth of plants,
2. regulates and purifies water,
3. recycles organic wastes and nutrients,
4. provides habitat for soil organisms, and
5. serves as physical support for building and
construction.
Soil health = soil’s capacity to function
Northern NY Field Crops Team

9. What is ‘soil?’
?
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10. Soil = solids + pore space
Composition of typical soil, by volume
Sand
Silt
Clay
From Univ. of Massachusetts Extension Vegetable Program, Soil Basics, part I
Northern NY Field Crops Team

11. Organic matter
• Wide range of organic
materials
– Living organisms
• Plants, roots
• Insects, nematodes
• Fungi, bacteria
– Non-living OM, products of
decomposition of living things
• Continuously decomposed,
new compounds
synthesized by other
microorganisms
• Holds mineral particles
together to form aggregates
Northern NY Field Crops Team

12. Pore space = air + water
• Air space provides gas
exchange to organisms and
plant roots
• Water is needed by plants
and organisms
• Soil water also contains
dissolved mineral
compounds & nutrients
needed by plants and
organisms
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13. Soil Aggregation, Structure
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14. Soil Aggregation, Structure
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15. Soil Aggregation, Structure
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16. Soil Structure → Water Infiltration,
Erosion Resistance
More storage
Less storage
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17. Characteristics of healthy, wellfunctioning soils
• Good tilth = desirable combination of particle size, moisture
content, aeration, water infiltration, drainage
• Sufficient nutrient content, not excessive
• Good, deep rooting depth
• Sufficient water storage and drainage
• Free from harmful toxins
• Plenty of active, beneficial organisms
• Few pathogenic, parasitic organisms
• Few weeds
• Resilient, able to resist degradation, erosion; recovers well
from disturbances
Northern NY Field Crops Team

18. Agriculture can damage soil health
•
•
•
•
•
Frequent, intense tillage
Plant monocultures, loss of diversity
Bare soil
Heavy fertilizer/chemical use
Heavy machinery traffic
→ Loss of soil structure → more runoff
→ Loss of soil through erosion
→ Loss of soil organic matter
→ Fewer, less active beneficial soil organisms
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19. Downward Spiral of Damage…
Intensive tillage, erosion, insufficient plant residues
Loss of SOM, compaction
Loss of aggregate structure
Compacted, crusty soil surface
Reduced infiltration, wind and water erosion
Loss of more SOM, topsoil, nutrients
Poor drainage, ponding, insufficient rooting depth
Fewer beneficial soil organisms, more pathogens
Crop yields decline
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20. Downward Spiral…
Reduced Soil Health
↓
Reduced Soil Function
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21. Compacted Soil Surface
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22. Water Erosion
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23. Wind erosion in NNY this winter
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24. So, how to minimize the damage?
1. Reduce frequency and intensity of tillage
operations, compaction
– No-till, strip-till, ridge-till, mulch-till, vertical-till
– All designed to disturb as little soil as possible
2. Increase organic matter inputs
– Cover crops, manure, compost, plant residues
3. Vegetative plant cover all year
– No bare soil, spring tillage
– Winter cover crops, leave plant residues
Northern NY Field Crops Team

25. So, how to minimize the damage?
4. Reduce compaction, field traffic
5. Crop rotation, perennials
– Long rotations
6. Manage pests and nutrients efficiently
– Test and monitor, apply only when needed at the right
time and place for optimal effect
Improvement takes time.
Northern NY Field Crops Team

26. Soil Health ↔ Soil Function
• How did we do?
– Understand the functions of soil and their
dependence on soil composition and
structure
– Explain to someone what soil structure is
and how it drives healthy soil function
– Think of some ideas how you might
preserve or improve your soil health
Northern NY Field Crops Team

27. Questions?
Northern NY Field Crops Team