cs45 composting web
TRANSCRIPT
CompostingCompostingNREM 461
D G B l dDr. Greg Bruland
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I. CompostingA. Def.
1. creation of humuslike OM outside of soil by mixing, piling, or storing OM under conditions conducive of aerobic decomp & nutrient cons.
B.Other traits
1. Periods of high temps not found in soils
C.Finished product = compost
1. used as
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D. Vermicomposting: process in which litter dwelling (epigeic) earthworms added to help transform OM
1. Piles kept shallow-why?
2. Composting worms: Eisenia fetida, E. andrei, Lumbricus rubellus, p g , , ,Perionyx excavatus, Eudrilus eugeniae
3. Earthworkers: Lumbricus terrestris
Lumbricus rubellusEisenia fetida
3Lumbricus terrestris
Main Types of Worms
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E. Composting Process
1 3 St f d1. 3 Stages of decomp.
Mesophilic: brief, sugars rapidly metabolized, temp. ↑
Thermophilic: next few weeks/months, decomp. of cellulose & more resistant OM, temp. ↑
Curing: weeks months temp ↓Curing: weeks-months, temp. ↓
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F. Requirements:
1 C diti f bl f i bi l th S h ?1. Conditions favorable for microbial growth. Such as?
2. To destroy pathogens need to reach 71oC (160oF) for >1 hour
3. Materials not good for compost?
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4. If OM deficient in nutrients, can be added
a. N, P, & lime
5. Often need to mix high C/N OM (leaves, straw, paper) w/ low C/N OM (grass clippings, legume hay, blood meal, sewage sludge, manure) to get proper C/N
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G. Finished product
1. C/N of OM ↓ until it reaches 10:1 – 20:1
2. 50-75% of C lost, mineral nutrients gen. conserved
3. Gen. have < 2%
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Pros & Cons of Composting
Pros Cons
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Case Study: OM Amendment Experiment
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(Bruland et al., 2009)
Study Site in Charles City County, Virginia
Virginia
N
Virginia
Dry BlockWet Block
N
3.5m*4m=14m2
Dry BlockWet Block1
5
3 2 4 5
2 5 3 130 m 5
4
1324
215313 m
5
3
2344
1425
To VA Highway 5 and James
2
1
3 1 4 2
3 4 4 51: 0 Mg ha-1
2: 56 Mg ha-1
Compost Amendment Level
30 m 51324
30 m
52344
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and James River3: 112 Mg ha-1
4: 224 Mg ha-1
5: 336 Mg ha-1
Grind All IncCBI Grinder
Grind All, Inc.Rockville, VA
Compost
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Amendment Hypotheses
(1) Denitrification will increase with increasing levels of compost amendmentsamendments
(2) P sorption will decrease with increasing levels of compost amendments
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Amendment load effects vegetative growth
0 Mg compost.ha-1 336 Mg compost.ha-1112 Mg compost.ha-1
Betula nigra (river birch)
16Soil %C = 1.4, C/N = 17 Compost %C = 35, C/N = 38
y = ‐0.0007x + 7.13R² = 0.85
7.2
7.4
y = 1 07e-0.003x1.01.21.4
m-3
)A. B.
dd c
b
y = -0.0003x + 6.93R² = 0 13
6.6
6.8
7.0y 1.07e
R² = 0.92
y = 1.03e-0.004x
R² = 0.970.20.40.60.8
BD
(g. c
m
pH
cc
c
b bb
bc abc
ab
abc
ababcab
ab
abba
R 0.136.4
y = 0.25x + 213.52R² = 0.54
240
300
360
0.0
C. c
m-3
)
C. c
m-3
)
C. D.
cd
dd
ab
cbcbc
y = 0.35x + 57.14R² = 0.93
150180210
W tt
Drier
y = 0.27x + 145.24R² = 0.86
0
60
120
180
0
MB
C (μ
g C
SOC
(μg
C
aba
bc
ab
bcdbc
bcd abab
a
a
ab
ab
ab bc
y = 0.39x + 61.66R² = 0.83
0306090
120 Wetter
y = -0.01x2 + 2.88x + 477.13R² = 0.49
700800900
1000
0
O. c
m-3
. hr-1
)
100c
m-3
)E. F.
c
b
d
0
y = -0.002x + 1.60R² = 0.87
1 82.22.63.0
y = -0.01x2 + 3.39x + 369.13R² = 0.91
200300400500600
DEA
(ng
N2O
PSI (
mM
Ps.
aba
abcabc
abcbc
abab
ab
c
cd
bccbc
bcab ab
aby = -0.004x + 2.08R² = 0.92
0.20.61.01.41.8
000 60 120 180 240 300 360
Loading Rate (Mg.ha-1) Loading Rate (Mg.ha-1)
D 0.20 60 120 180 240 300 360
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50 110336
Loading Rate
050-110
Organic Amendments
(+): Plant growth, BD, MBC, DEA*
(-): pH, PSI
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