1. Chapter 15
Organic Amendments

2. Objectives After completing this chapter, you should be able to:
Explain the benefits of organic amendments
Describe how to use animal manure
Describe how to use biosolids
Explain composting
List environmental side effects of fertilizers and amendment

3. Organic Amendments Benefits Raise soil nutrient levels
Contain a mixture of nutrients and secondary and trace elements
Act as soil storehouse for nutrients
Contain much organic matter that improves soil physical condition
Support growth of beneficial organisms
Can produce higher yields than complete fertilizers
Good use of waste products

4. Animal Manure Benefits Good amounts of nitrogen and potash
Adds organic matter to the soil
Longer-lasting effects than chemical fertilizers

5. Animal Manure (cont’d.)
Problems
Excessive application of phosphorus
Excessive application of manure
Nitrates leaching under animal confinement areas
Organic runoff to lakes and streams
Transporting human pathogens
Gaseous air pollutants
Human health considerations

6. Animal Manure (cont’d.)
Content
Primarily animal urine and feces
Liquid
Solid
Nutrient content factors
Type of animal
Amount of animal bedding
Age and health of animals

7. Animal Manure (cont’d.)
Nutrient losses from manure composed of urine
Contains about 50% of the nutrients
A great deal of it drains away through barn floors, feedlots, and manure heaps

8. Animal Manure (cont’d.)
Handling manure
Solid
Best spread immediately on unfrozen ground and quickly plowed into soil
If cannot be mixed into the soil immediately, it should be stored properly and then applied when it can be plowed
Liquid
Best for saving nutrients
Can be spread through irrigation
Best injected into soil

9. Animal Manure (cont’d.)
Best management practices
Test manure and soil for nutrients
Base application rates on phosphorus needs
Spread evenly with calibrated equipment
Incorporate or inject into soil as soon as possible
Increase time animals spend on pasture rather than on a feeding operation
Design the animal feeding program to reduce phosphorus content of manure

10. Animal Manure (cont’d.)
Sensitive areas
Environmental concerns
Nearby waters
Soil or terrain that promotes runoff or leaching

11. Animal Manure (cont’d.)
Regulations for CAFOs
Require a nutrient management plan if large animal numbers (1000 cattle or 2500 swine) are present
Minimize nutrient excretions
Store manure properly
Land application at agronomic rates for N and P
Setbacks and buffers
Periodic soil testing

12. Biosolids Sewage sludge Benefits Problems Disposes of human waste
Provides plant nutrients
Problems
Pollutants: heavy metals and pesticides
Human pathogens: diseases and parasites
Pest vectors: insects and rodents
Soluble salts
Odor

13. Biosolids (cont’d.) Application guidelines
Federal rules set standards application
Apply to common sites of land application, such as agricultural land, nurseries, or reclamation sites
EPA classifies biosolids that can be spread on land as Exceptional Quality (EQ) or High Quality (HQ)

14. Compost Benefits Reduces carbon to nitrogen ratio
Reduces weight and volume of organic wastes
Mineralizes slowly; better enhances soil
Heat in piles may kill weed seeds
Can encourage organisms that suppress root pathogens

15. Compost (cont’d.) Three stages of composting
Mesophilic: decay begins and temperature rises
Thermophilic: temperature rises to around 150°F
Curing: stabilization occurs

16. Fertilizers and the Environment
Concerns
Animal and human health
Nitrates
Eutrophication
Overgrowth of algae
Hypoxia
Low oxygen conditions in water
Phosphorus discharge

17. Fertilizers and the Environment (cont’d.)
Energy costs
High energy costs
Increased farming costs
Human changes to the global nitrogen cycle
Humans now create as much biologically active nitrogen (e.g., nitrates, ammonia) as all the natural processes combined by fertilizing and cultivating legumes

18. Fertilizers and the Environment (cont’d.)
Best management practices
Conservation tillage and efficient irrigation
Proper handling of manure
Efficient delivery times and application methods
Precise application and careful use of fertilizers
Use of slow-release fertilizers and controlled drainage
Vegetative buffers and cover cropping
Budgeting nutrient inputs
Organic and sustainable agriculture practices

19. Summary This chapter reviewed several topics
Manure, biosolids, and composting provide benefits by adding nutrients and organic matter to the soil
It is better to use these wastes rather than just dispose of them
They do present some environmental concerns
Managed properly, these organic amendments are a safe and an important resource