nitrogen release and disease suppressive activity of four ......nitrogen release and disease...
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Nitrogen release and disease suppressive activity of four compost amendments on three vegetable farms Lori HoaglandDept. of Horticulture and Landscape ArchitecturePurdue UniversityPresented by Liz Maynard, 219-531-4200 x4206; [email protected]
+Outline
Relationships between soil health and pest severity
Our on-farm trials investigating fertility amendments, soil health and pest severity
How you can apply this information
+ Pest outbreaks on your farmSusceptible host
Favorable environment
Unwanted pest
The perfect storm
+ Soil health
http://www.lawrieco.com.au/about-us/?id=7
Foundation for sustainable crop production
+ Soil physical properties Compaction affects:
- water infiltration & drainage
- soil biological activity
- seed germination & root growth
+
Salinity: salt content - soil tilth & plant health
- challenge in high tunnels
Nutrient availability:- over & under fertilization
pH: acidity/alkalinity of soil- nutrient availability
- pathogen severity
Soil chemical properties
Excess nitrogen
+ Soil biological properties
“The soil’s livestock”
Regulate key soil processes:- influence soil structure- detoxify pollutants- regulate nutrient cycling- mediate pathogen and
insect pressure
It’s Alive!
+ Disease suppressive soil
Pathogen fails to cause infection despite susceptible host & favorable environment
Biologically mediated:- competition for resources- parasitism- antibiosis- induced systemic resistance
(stimulation of a plants immune system)
Can be induced by managementAntibiosis
+ Organic fertility amendments Animal manures, compost,
vermicompost, specially formulated products Supply nutrients Provide soil organic
matter Have suppressed pests:
- soil-borne pathogens
- foliar pathogens
- insectshttp://www.compostforsoils.com/index.php?id=38
+ Challenge: Amendments must mineralize before
nutrients are available for plant uptake
Mineralization rate depends on:
- amendment composition - environmental
conditions - management practices- soil health
http://www.rothamsted.ac.uk/aen/smbweb1/paradox.html
+ Challenge: Not all composts are pest suppressive
Suppressive activity depends on:- feedstocks- processing conditions- pest
Still no perfect recipe or reliable tests to predictsuppressive activity
Suppressive activity well documented in container based systems, but results variable in field trials
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Our study (2013-2015)Purdue: Lori Hoagland, Elizabeth Maynard, Natasha Cerruti, Dan EgelGrowers: Jeff Evard, Ben Nava, Steve Spencer
+ On-farm research trials LIFE Farm, Martinsville, IN
Feel Good Farm, Sheridan, IN
EcOhio Farm, Mason, OH
+ Methods
2013Red Cabbagecv. Red Express
2014Acorn squash
cv. Sweet Reba
2015Paste tomato
cv. TBD
• 3 year vegetable crop rotation• Winter cover crop (rye & vetch)• Repeated applications of 4 fertility amendments• Soil, pest and plant measurements
+Amendment application rate
Product (N, P, K) Rate Applied 2013 (lb/A)
Rate Applied 2014 (lb/A)
Chicken litter (3-4-3) 8000 6000
Animal byproducts (8-5-5) 3000 2250
Plant & animal byproducts(7-5-10)
3430 2570
Vermicompost (1.2-2-1) + Chicken litter (3-4-3)
10000+4000
7500+3000
Focus on N (tends to be most limiting nutrient) Rate depends on the needs of the crop Assume 50% release rate
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At planting Midseason At harvest Fall0
50
100
150
200
250
LIFE Feel Good Farm EcOhio
2013: Soil N availability varies by amendment and farm
At planting Midseason At harvest Fall0.00
50.00
100.00
150.00
200.00
250.00
Chicken litter Animal byproducts
Plant & animal byproducts Vermicompost + chicken litter
lbs
N/a
c
Soil N availability across farms
lbs
N/a
c
Soil N availability across amendments
+ 2013: Amendments influence black rot severity & cabbage yield
0
10
20
30
40
50
60
70
6/25 6/30 7/5 7/10 7/15 7/20
Fol
iar
Bla
ck R
ot S
ymp
tom
s (%
)
Date
FT NS
VD VMa
A
AB
C
BC
(Xanthomonas campestris)
VermicompostPlant & animal
Chicken Animal byproducts
+ 2014: Amendments influence squash N uptake
37
37.5
38
38.5
39
39.5
40
40.5
41
41.5
Additive effect?
Squash leaf chlorophyll (SPAD) across farms
+2014: Amendments influence susceptibility to silverleaf whitefly
0
0.5
1
1.5
2
2.5
3
3.5
Silverleaf whitefly severity rating
(Bemisia argentifolia)
+ 2014: Amendments influence soil health & susceptibility to damping off by Rhizoctonia solani
0
0.5
1
1.5
2
2.5
3
baseline animal byproducts
chicken litter plant/animal worm castings0
2
4
6
8
10
12
14
16
root
rat
ing
treatments
aver
age
leng
ht c
m
Life 2014
shoot length root length root rating
+ Conclusions
Nutrient release varies by amendment and farm- potential nutrient additive effect with some
amendments
Amendments influence pest severity- in some cases effects were consistent across
farms
- in some cases pest severity was correlated with nitrogen availability
- in some cases pest severity was correlated with soil quality
+ How can you apply this information?
+ On-farm research Best way to determine what will work best
on your farm Resources:
- Local extension educators- Sustainable Agriculture Research and Extension(SARE)
- On-farm research guide
- Grant opportunities
www.sare.org
+ Soil quality testing
Monitor your soil over time
On-farm soil quality tests:- NRCS Soil Quality Test Kit
- Soil quality scorecards
- Solvita test
Laboratory tests:- Cornell Soil Health Lab
- Comprehensive assessment
http://soilhealth.cals.cornell.edu
+ Nutrient management Avoid over and under fertilization
OSU organic fertilizer calculator:http://smallfarms.oregonstate.edu/calculator
Soil and plant tissue tests:- basic soil nutrient tests
- pre sidedress soil nitrate tests (pre sidedress)
- plant tissue tests
(more expensive but more accurate)
Petiole sap tests (N & K)- Midwest Veg Prod Guide
+ Disease suppressive composts Stable, mature and of consistent quality
General recommendations (Hoitink et al., 1997)1) cure at least 4 months or more 2) incorporate several months before planting3) maintain high moisture (40-50%) during curing and
inoculate with beneficials
May be more suppressive- Higher C:N ratio- Hardwood bark compost - Vermicompost
