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Organic Systems: Building Soil Fertility and
Improving Soil Quality
Craig Cogger, Doug Collins, Andy Bary
WSU PuyallupDan Sullivan and Eric GaleOregon State University
Overview
•Estimating plant-available N release from organic amendments Field and laboratory
research
•Nutrient management effects on soil quality
Nitr
oge
n (
% d
ry m
att
er)
0
2
4
6
8
Organic N % NH4-N %
NO3-N %
Organic amendments in field and laboratory nitrogen researchOrganic amendments in field and laboratory nitrogen research
Days
0 20 40 60 80
Dec
ompo
sitio
n (%
)0
20
40
60
80
Specialtyproducts
Other composts
Days
0 20 40 60 80
Dec
ompo
sitio
n (%
)
0
20
40
60
80FreshDairy solids
Composteddairy solids
Days
0 20 40 60 80
Dec
ompo
sitio
n (%
)
0
20
40
60
80
Broiler litter
Amendment decomposition in soil
Plant Available N
Days
0 20 40 60 80
PA
N (
%)
0
20
40
60
80
Broiler litter
Days
0 20 40 60 80
PA
N (
%)
0
20
40
60
80
FreshCompost
Dairy solids
Days
0 20 40 60 80P
AN
(%
)
0
20
40
60
80 Specialtyproducts
Other composts
C:N = 9
C:N = 27
C:N = 20
C:N = 7
C:N = 16
Amendment C:N
0 5 10 15 20 25 30 35
Ful
l-Sea
son
PA
N
(% o
f am
endm
ent N
)
-20
0
20
40
60
80
100
120Broiler litterDairy solidsRabbit manureYard trimmingsSpecialty productsComposts
Amendment C:N vs. plant-available N (field)
Sample calculations
• How much of this fertilizer should I apply?
• How do these two fertilizers compare?
• What’s the cheapest source of available N, P, K, etc.?
• Does this program match my fertilizer recommendation?
ORGANIC FERTILIZER CALCULATOR
http://smallfarms.oregonstate.edu
Basis for Organic Fertilizer Calculator
http://smallfarms.oregonstate.edu
“Organic Fertilizer Calculator" estimates of plant-available N (PAN)
Fresh Amendment
total N
Example Fresh Amendment
C:N
PAN
28 days
PAN
full season
% dry wt. Approx. % of total N % of total N
1 Solid manure
w/bedding
35 < 0 0
2 Dairy solids
18 0 15
4 Broiler litter
9 30 45
6+ Specialty products
less than 6
60 75
Organic Systems Research – started 2003Nutrient Management Weed Ecology and Management
Soil Quality
Crop Yield and Quality
Economics of Crop Production
Insect Predators and Pests
Soil Amendments
•Chicken (Broiler) litter: low C application (CKN) (1.8-2.7 dt/ac)
•Mixed on-farm compost: high C application (OFC) (13-17 dt/acre)
Cover Crops
Relay plantedLegume (RLY)
Post-HarvestCereal &
legume (PH)
Short-termGrass-legumePasture (LEY)
Measurements: Soil Quality•Bulk Density•Infiltration •Particulate OM•Enzyme activity•Nematodes•Collembola•Compaction •Aggregation of particles•Nitrogen cycling•Microbial community structure
Soil pH, K, and OM2006
pH Exch. K OM mg/kg g/kg
Ley 6.2 a 229 b 38
Fall 5.9 b 370 a 41
Relay 6.0 b 375 a 42
Low C 5.8 b 247 b 37 b
High C 6.3 a 402 a 44 a
CC x amd *** *** **
CKN OFC CKN OFC CKN OFC
Bu
lk D
ensi
ty, g
/ml
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.42004 20062005
a ba
b
ab
Bulk density affected by amendment
Amendment
CKN OFC CKN OFC CKN OFC
Infi
ltra
tio
n, m
m/m
in
0
1
2
3
4
5
6
7
aa
a
b
a
b
Ley Post Harvest Relay
Infiltration affected by amendment and rotation
Particulate Organic Matter (POM) C affected by amendment
Jan 04 Jun Jan 05 Jun Jan 06 Jun Jan 07 Jun Jan 08
PO
M C
, g/k
g so
il
2
4
6
8
10
12
14
16
18
20
Low CHigh C
all dates significant @< 0.001
Dehydrogenase as an indicator of biological activity
Jan 04 Jun Jan 05 Jun Jan 06 Jun Jan 07 Jun Jan 08
De
hyd
rog
ena
se a
ctiv
ity, u
g T
PF
/g s
oil/
h
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Low CHigh C
*
*
**
*
A soil nematode community
Aporcelaimellus- predator; 1.9 mm
Cephalobidae- bacterivore;
0.5 mm
Aphlenchoides- fungivore; 0.3mm
Rhabditidae; bacterivore
0.1mm
Total Nematodes
Jan Jul Jan Jul Jan Jul Jan
Nem
atod
es 1
00 c
c-1
2000
4000
6000
8000
10000
12000
14000CKN OFC
**
**
****
05 06 07
CKN OFC
Enrichment Index
2005-SU 2006-SU 2007-SU
Enr
ichm
ent I
ndex
80
85
90
95
100
**
*
Maturity Index
2005-SU 2006-SU 2007-SU
Mat
urity
Inde
x
1.0
1.2
1.4
1.6
1.8
2.0
**
*
Nematode ecological indices
Summary•Amendment had significant effects on bulk density, infiltration, dehydrogenase, nematodes, and organic C •Nematodes more numerous following broiler litter (low C), but more diverse following compost (high C)•Cover crop has had rotational effects; other effects are still evolving.
