Transcript organic.tfrec.wsu.edu

What’s New
with Mulches ?
Alfalfa mulch in apple
David Granatstein
Center for Sustaining Agriculture and
Natural Resources, Wenatchee, WA
Credits
Funding support from WA Tree Fruit Research
Commission and Small Planet Foods, Inc.
Co-operators: Kent Mullinix, Gene Hogue, Leo
Garcia, Tom Auvil
Technical Support: Laura VanWechel and
Elizabeth Kirby
Thanks to Keyes Fibre Inc. for supplying
spray-on paper pulp and to Simplot
Soilbuilders for use of the Enviroscan system.
New Treatments:
• Mint slugs
• Colonial
Bentgrass
Mint slugs
June ‘02
Renewed wood
chips
Wood chip – April ‘02
Fall-planted Dwarf white clover
Late summer 2000
Early spring 2002
Rodents – the weak link for clover.
Lessons Learned So Far
Weeds
• Winners – shredded paper, wood chip, clover
• Chopped alfalfa acts like potting soil
Shredded paper mulch
Wood chip mulch
400
WVC Mulch Trial
BL weeds/m2
350
Weed Control by
Mulches – 6/1/00
300
250
200
150
100
50
0
% weed cover
Control
Wood
chip
Paper
Alfalfa Mustard
Rye
Clover
Paper
Alfalfa Mustard
Rye
Clover
50
45
40
35
30
25
20
15
10
5
0
Control
Wood
chip
Lessons Learned So Far
Weeds
• Winners – shredded paper, wood chip, clover
• Chopped alfalfa acts like potting soil
Water
• 25% water savings possible
• Clover living mulch has minimal competition
Mulched
Soil moisture
conservation
with a wood
chip mulch –
Gala/M26 6th
leaf
10-day
interval
Unmulched
6-day interval
Soil Depth (cm)
Effect of Orchard Mulching on Soil
Moisture Depletion
50
30
20
10
0.0
0.5
1.0
1.5
Moisture Depletion (mm)
Mulch
Unmulched
2.0
Effect of mulch on soil moisture
A = control; B = wood chip; G = clover; more negative centibars = drier
(-)Centibars
0.0
-20.0
-40.0
-60.0
-80.0
5/3
6/5
6/28
7/23
8/15
9/20
Date (2001)
10 cm depth
B 10 cm
A 10 cm
G 10 cm
(-) centibars
0.0
-20.0
-40.0
-60.0
-80.0
5/3/01
6/5/01
6/28/01
7/23/01
8/15/01
Date (2001)
30 cm depth
B 30 cm
A 30 cm
G 30 cm
9/20/01
Lessons Learned So Far
Nitrogen
• Alfalfa N boosts tree growth, fruit yield, but can be
excessive – caused alternate bearing
• Clover able to supply adequate N for trees; need to
work on timing
Nitrogen release over 3 weeks from orchard soil
(6th leaf Red Delicious/M26 – Wenatchee, WA)
NO3-N in tube (lbs/acre)
80
70
60
50
07/24/2001
40
07/31/2001
30
08/07/2001
20
10
0
A
0-6” depth
B
C
D
E
F
A – control plot; tube + cover; no clover
B – control plot; tube + cover + clover clips
C – clover plot; tube + cover + clover clips
D - clover plot; tube – cover + clover clips
E – control plot; no tube F – clover plot, no tube
Lessons Learned So Far
Nitrogen
• Alfalfa N boosts tree growth, fruit yield, but can be
excessive – caused alternate bearing
• Clover able to supply adequate N for trees; need to
work on timing
Tree Growth and Yield
• N effect from alfalfa, clover led to most growth
• Wood chip, shredded paper also boosted growth
over the Control
4-Yr % Increase TCSA
Alfalfa (D)
Clover (GH)
Wood chip (B)
Paper (C)
Mustard
Rye
Control (A)
Cum. Yield 3-Yr (kg/tree)
90 a
75 b
74 b
72 b
70 b
60 c
59 c
66
61
48
52
55
53
50
30
TCSA (cm2)
Tree Growth and Yield
Red Delicious/M26
Wenatchee, WA
(cm2)
25
20
15
10
1999
2000
A
2001
B
C
2002
D
2003
GH
Soil Property Changes with Mulch
SOM
(%)
Control
Wood chip
Shr. paper
Alfalfa hay
Mustard
Rye
Clover (mow)
Clover (burn)
P
B.D.
(g/cc)
1.56
1.47
1.66
1.63
1.62
1.86
1.82
1.76
1.38
1.37
1.36
1.40
1.30
1.32
1.32
1.32
NS
NS
Infiltration
(min/inch)
Soil Temp.
(oF @ 2” depth)
1.88 abc
1.03 cd
0.78 d
1.02 cd
2.62 a
2.17 ab
1.63 bcd
nd
66.8
55.2
54.0
58.0
61.1
60.0
54.9
56.2
0.003
0.000
SOM: 0-6”, April 2001; Bulk density: 0-6”, Sept. 2001; Infiltration: Aug. 2001;
Soil temp.: 4/19/01; Wenatchee Valley College orchard
Paper Decomposition Test
• Incubate soil sample in Petri dish with 25 mm square of
•
graph paper
Weekly count # of squares decomposed
Control
Wood chip
Shr. paper
Alfalfa hay
Clover
0%
0-5%
5-30%
0-3% (fungal growth)
10-100%
Wenatchee Valley College:
Alfalfa mulch and clover cover crop increased
indicators of enhanced nutrient turnover
1800
Nemas per 100 g soil
1600
1400
1200
Alfalfa hay
Chips
Paper
Rye
Clover
Control
1000
800
600
400
200
0
EO nemas/10 g soil
All bacterivores
(T. Forge, PARC)
Naches:
Alfalfa hay mulch increased indicators of enhanced
nutrient turnover, and reduced buildup of P. penetrans
160
No mulch
Nemas per 100 g soil
140
Mulch
120
100
80
60
40
20
0
EO nemas/10 g soil
Enrichment Index
P. penetrans
(T. Forge, PARC)
Nem atodes / 100m l soil
Effect of Mulches on Nematodes in
Orchard Soil - Summerland, BC
600
Check
500
VBio
400
PM
300
VBio+PM
200
KBio+PM
100
AlfM
0
Bactiv. (x10)
(Hogue et al., 1998)
Omni/Pred
Pratylenchus
Geotex
(T. Forge, PARC)
Release of N from composts, alfalfa hay
and fish meal organic fertilizer in 2002
90
80
Percent N loss
70
Bare
Mulch
60
50
40
30
20
10
0
Poultry
Dairy
Ogogrow Alfalfa
Fish
(T. Forge, PARC)
Recommended (tentative) application rates (in
tons/acre) to release 100 lbs mineral N/acre in first year
Poultry
compost
Dairy
compost
Ogogrow
Alfalfa hay
Fishmeal
fert.
% N (start)
4.8
1.0
1.5
3.7
9.2
% N lost
47
29
31
47
82
Tons/acre to
yield 50 lbs
N/acre
1.1
8.5
5.5
1.5
0.4
lbs N/acre if
add 25 t/acre
1136
147
227
862
n.a.
(T. Forge, PARC)
New Directions
• ‘Grow Your Own Mulch’
• Quincy Deficit Irrigation Trial
• Cover crop gone wild !
• Spray-on paper mulch
‘Grow Your Own Mulch’ Trial
Control (companion grass)
Forage grass
Alfalfa
Alfalfa / grass mix
June 2002
Control
Grass
hay
‘Grow Your
Own Mulch’
Trial
Grass hay
Sept 2002
Deficit, no mulch
Deficit + mulch
Quincy Deficit Irrigation Trial
Spray-on Paper
Mulch
Applied August 2001
Cost and longevity are key
issues.
August 2002
Test in Oroville
Pulp from Keyes Fibre Inc.
proved suitable.
August 1999
August 2002
Trefoil insectary mix planted in
alleys June 1996.
Thank
you !