Manure + Cover Crops Research & Experience - Dr. Dan Anderson, Iowa State University, from the 2020 Iowa Pork Congress, held January 22 - 23, 2020, Des Moines, IA, USA.

1. Soil Health and Manure
Daniel Andersen
Associate Professor and Extension Specialist
Agricultural and Biosystems Engineering

2. Benefits of livestock manure
• Less need for purchased fertilizers
• Add micronutrients to soil
• Improve soil health
ü Increase soil organic matter
ü Improve porosity & aggregate stability
ü Reduce soil bulk density
ü Increase microbial activity & nutrient cycling
2

3. Manure and Carbon
• How much of the
carbon we add ends up
as soil organic matter
• Research suggests for
all manures it is about
12%

4. Manure and Carbon
Manure Type
Total
Solids
Volatile
Solids
Organic
Carbon
Application
Rate
Carbon
Added
Change in Soil
C Content
Years for
1%
increase
(%) (%) (%) (lb/acre) (ppm/year) (years)
Deep-pit
Swine
8 6 3.5 3,500 gpa 1,041 62 160
Dairy Slurry 6 4 2.3 15,000 gpa 2,933 176 57
Layer Manure 40 34 19.7 4 tons/acre 1,576 95 105
Turkey Litter 50 40 23.2 10 tons/acre 4,640 278 36
Beef Feedlot 67 30 17.4 20 tons/acre 6,960 418 24

5. Poultry Manure Study
Fertilizer
Source
Total Soil Carbon
(SOC) (g/kg soil)
Total Soil Nitrogen
(g/kg soil)
C:N ratio POM POC
High PM 23.0 (3.7) A 2.0 (0.3) A 11.8 (1.0) AB 6.7 (1.4) A 4.6 (1.1) A
Low PM 21.9 (3.4) A 1.9 (0.3) A 11.4 (0.4) B 6.1 (1.1) A 3.6 (0.8) AB
UAN 20.8 (3.5) A 1.8 (0.2) AB 11.7 (0.5) AB 4.6 (0.7) B 2.5 (1.2) BC
None 17.9 (2.9) A 1.5 (0.2) B 12.4 (0.7) A 3.7 (0.4) B 1.7 (0.3) C
• Near Ames, Iowa
• 20 years of treatment

6. Manure injection: Effect on cover crop
Rye cover crop growth with visible streaking at NERF April 6, 2016
6

7. Cereal rye cover crop N uptake
7
Research funded by Iowa Pork Producers Association and Calcium Products Inc.

8. Corn phase yields
-26 bu
+27
bu
+5 bu
+64
bu
8
+16
bu
+29
bu
Research funded by Iowa Pork Producers Association and Calcium Products Inc.

9. Monthly nitrate-N levels in corn phase
2016 - 2017
9
Research funded by Iowa Pork Producers Association and Calcium Products Inc.

10. Research design
• Research design:
• 36 soil columns, divided into 6 treatments
• Treatments: 6 columns each
• Soil Only
• Cover Crop Only - cereal rye
• Manure Only
• Cover Crop + Immediate Swine Manure
Application
• Cover Crop + Two Week Delay Swine
Manure Application
• Cover Crop + Four Week Delay Swine
Manure Application

11. Methods: PREPARATION AND LEACHING
• Cover crop planted at
75lb/acre (aiming for 10
plants in each column)
• 30 mL liquid swine manure
applied to designated
columns by pipette
• Columns leached every week
with 150 mL water for 8
weeks
• Subsample of 50 mL was
analyzed for nitrate
concentration

12. Results

13. Results

14. Results