Download Chapter 8

Chapter 6
Organic Matter
T6-1
Soil Science & Management, 4E
Objectives
• Explain what organic matter is and
how it forms
• Describe what organic matter does in
the soil
• List several ways to maintain soil
organic matter
• Discuss the problem of nitrogen tie-up
• Define organic soil, listing uses and
problems
T6-2
Soil Science & Management, 4E
Terms to Know
•
•
•
•
•
•
•
•
•
T6-3
Amino acid
Carbon-nitrogen ratio
Cellulose
Colloids
Compost
Cover crop
Fibric
Green manure
Hemic
•
•
•
•
•
•
•
Hemicellulose
Humification
Humus
Labile
Lignin
Muck
Nitrogen depression
period
• Organic matter
Soil Science & Management, 4E
Terms to Know
•
•
•
•
•
•
•
T6-4
Organic soils
Peat
Recalcitrant
Proteins
Sapric
Starch
Subsidence
Soil Science & Management, 4E
The Nature of Organic Matter
• Chemical makeup of organic matter
Figure 6-2
T6-5
Soil Science & Management, 4E
The Process of Decay
• Factors affecting organic matter
T6-6
Soil Science & Management, 4E
Functions of Organic Matter
•
•
•
•
•
T6-7
Nutrient and water storage
Nutrient availability
Soil aggregation
Preventing erosion
Undesirable effects
Soil Science & Management, 4E
Maintaining Soil Matter
•
•
•
•
•
•
•
•
T6-8
Conservation tillage
Crop residues
Green manuring and cover cropping
Crop rotation
Organic matter additions
Mulches
Increasing soil water
Maximum cropping
Soil Science & Management, 4E
Nitrogen Tie-up and Composting
Figure 6-7
T6-9
Soil Science & Management, 4E
Nitrogen Tie-up and Composting
Figure 6-8
T6-10
Soil Science & Management, 4E
Nitrogen Tie-up and Composting
• Composting
Figure 6-9
T6-11
Soil Science & Management, 4E
Organic Soils
• Horticultural peat
Figure 6-11
T6-12
Soil Science & Management, 4E
Organic Matter and
Global Climate
• Soil organic matter affects ecosystems,
growers, and global climate
T6-13
Soil Science & Management, 4E
Summary
• Amount of organic matter depends on:
– Vegetation
– Climate
– Soil texture
– Soil drainage
– Tillage
• Improves soil
• Preserve organic matter
T6-14
Soil Science & Management, 4E