Organic amendments and cover crops can
enhance yield stability and agricultural
resilience in Canadian vineyards
Mehdi Sharifi
Summerland Research and Development Centre
1

Context
• Light soil textures and low soil organic matter;
• Low soil CEC;
• High potential for nutrient losses during fall and winter; and,
• Climate variations and increase in frequency of extreme events
resulted in greater yield variability.
2

Greater interest in use of soil organic
mulches and amendment
• Growing interest in sustainable wine production  need for
alternative fertilization and pests/weed control methods;
• Pressure for more strict regulations on use of glyphosate (i.e.
2020 glyphosate free wine);
• Availability of yard waste and forestry by-products and needs
for recycling; and,
• Enhanced soil health  yield stability/reliability and
agricultural resilience goal in changing climate.
3

Objectives
i. Evaluate the effect of mulch and/or compost on wine grape yield
stability
ii. Assess the changes in soil C and N dynamics down the soil profile
with mulch and/or compost application as a possible mechanism;
and,
iii. Link microbial community function with soil C and N dynamics in
soil profile.
SuRDC P42 vineyard,
summer 2018
4

Study Site
• Summerland Research and
Development Centre, (49°34′N,
119°39′W);
• Cool winters (−1.4 °C), warm summers
(19.4 °C), and low annual precipitation
(326 mm yr−1);
• Skaha sandy loam (Brown Chernozemic
soil);
o pHwater=7.4
o total C=17.8 mg g−1
o total N= 2.1 mg g−1
o Bray P= 39.0 μg g−1
5

Experimental set up
• Planted 2011 (Merlot/SO4); 1.2 m X 3.0 m spacing (2778 vines ha−1)
• Drip irrigation;
• RCBD, with 5 replications;
• Treatments
Control (no fertilizer or amendment);
o Fertigated daily for 6 weeks at 40 kg N ha-1year-1
o Fertigated daily for 6 weeks at 40 kg N ha-1year-1 + recommended P, K and B
129 ton ha-1 DW Mulch + fertigated daily for 6 weeks at 40 kg N ha-1year-1;
129 ton ha-1 DW Mulch + 6.1 ton ha-1 DW Compost (20% estimated supply
from compost at 40 kg N ha-1).
6Hannam et al. 2016. Can. J. Soil Sci. 96:23-36

Surface applied mulch and compost characterization (n=4)
Unit Mulch SD Compost SD
Moisture % 163 78.1
EC dS/m 0.294 0.051 1.44 0.05
pH - 5.75 0.06 8.67 0.08
Total C % 48.8 0.61 29.0 2.80
Total N % 0.352 0.014 1.46 0.09
Nitrate-N mg kg-1 25.8 0.51 18.9 1.07
Ammonium-N mg kg-1 7.72 4.57 17.1 2.82
• Compost: 1 year old and made from ~ 15% grape pomace, 20% straw, 25% shredded bark and
wood chips, and 40% cow manure.
• Mulch: shredded bark and wood (primarily from Pinus contorta var latifolia and Picea glauca)
7

Maintenance and Harvest
8

Soil sampling, August 2018
9
Depths
0-15 cm
15-30 cm
30-45 cm
45-60 cm
Total soil C content
by combustion
using a CHN
analyzer (LECO
628)

Respiration Experiment
o Incubation: dark, 25oC, 90% RH
o Trap exchanged at 2, 4, 7, 10, 14,
22, 30, 38, 48, 58, 73, 88, and
102 days
o Double endpoint titration with Titrino
848 autotitrator
o 500 mL mason jars with 0.5M NaOH
alkaline trap
o Moisture content: 49.1% ± 4.7%
o 0-15cm and 15-30cm samples were
packed to 1.2g/cm3
o 30-45cm and 45-60cm were packed
to 1.5g/cm3.
First-order kinetic model
Cit =C0 [1-exp(-kt )]
o Cit C mineralized (mg C
kg−1 soil) during the
incubation time t (d),
o C0 potentially
mineralizable C (mg C
kg−1 soil)
o k (d−1) mineralization
rate coefficient
10

Long-term aerobic incubation for dissolved organic C
Moisture adjustment: 46% ± 12%
Incubation: dark, 25oC, 90% RH Extraction, CaCl2, 0.01N Filtration of extracts,
0.45 µm and analysis
with DOC analysis (TOC-
L CPH, Shimadzu, Kyoto,
Japan) 11

Microbial Methods
Total community DNA extraction;
Microbial community function, The abundance of genes associated with C
cycling enzymes were assessed using qPCR. Quantified genes included those
associated with the breakdown of:
oPolyphenolic C compounds (laccase; 1.5 µM Cu1A-F/Cu2-R; Kellner et al.,
2007)
oHemicellulose (glycoside hydrolase; 1.0 µM fungGH11-F/R; Barbi et al.,
2014)
oCellulose (cellobiohydrolase; 1.0 µM fungi-cbhI-F/R; Edwards et al., 2008)
oOligosaccharides (0.75 µM β-glucosidase; Bact-bglu2-F/R; Canizares et al.,
2011)
12

Results: Yield stability and reliability
13

Changes in soil C dynamics with surface applied high-C material:
First order kinetic model
Although mulch generated a greater C0 in 0-30 cm soil depth (57%) compared with
mulch+compost, but the trend was reverse in 30-60 cm (11%) which confirm greater
downward movement of C as a result of compost use.
14

The high C surface applied material modifies soil C down
the soil profile
Interactions ** Amendment ***; Depth ***
Total C/DOC ratio= 1750:1 15

Bacterial and fungal C cycling gene
abundance 8 years after
establishment (at the beginning of
the incubation study)
Total Extractable DNA (µg DNA g-1 dry soil):
mulch+compost (15.8) > mulch (14.0) > control (8.2)
16

Summary
• Mulch and mulch+compost significantly improved yield stability in 5
years likely due to buffering soil moisture and enhancing soil health;
• A significant contribution of mulch and mulch+compost to soil health
was measured i.e. greater quantity of soil C fractions and enhanced
soil respiration;
• Laccase, glycoside hydrolase, and β-glucosidase overall functional
capacities in mulch+compost treatments were approximately double
that of control treatment; and,
• There were strong relationships between the functional capacity of
the microbial communities and both the amount and respiration of
labile C in soil.
17

Screening Cover Crop Species
for Okanagan Valley Vineyards
18

Ground Cover Management:
Cover Crops
• Positive effects on yield and/or sensory attributes and soil
function are reported;
• Essential services: water infiltration, carbon
sequestration, nutrient supply and retention, weed
suppression, biological control agents, microbial activity
and diversity, and reduction of soil erosion; and,
• Results variable among years under influence of grape
varieties, growth stages, cover crop species and
management, climate, and soil resource availability and
properties.
19

Alleyway Cover Crops
Covert Family Organic Estate
2019 Cover crops screening experiment
Dates:
Jun 7, Alley cover crops were seeded
July 31, Pictures were taken
Aug 2, Cover crops were mowed
20

P85- Tillage Radish + Perennial RyegrassP79- Ricegrass + Buckwheat
21

P92- Crimson clover P93- Cereal rye + Hairy vetch
22

Under Vine Cover Crops
Covert Family Organic Estate
2019 Cover crops screening experiment
Dates:
May 30, in-row cover crops were seeded
July 18, Pictures were taken
Aug 2, Cover crops were mowed
23

Ladino clover
Buckwheat
24

Turnip
Phacelia
25

Winfred Brassica
Spring Lentil
26

Cover crops screening table
# Cover Crop Species Scientific Name
Annual
(A)/Peren
nial (P)
Establish
ment;
Early/
Late
Growth
rate
Canopy
coverage
Adequity
of
chosen
seeding
rate
Weed
suppress
ion
Early
maturing
1
Drought
toleranc
e(L, M,
H)
Resistan
ce to
mowing/
Regrowt
h after
first
mowing
Inrow Covert Kalala
1 Crescendo Ladino Clover Trifolium repens cv. Ladino 14 14 P H-Late L H M H-Late L L H
2 Winfred Brassica Brassica napus cv. Winfred 14 14 A H-early H H L H L L M
3 Buckwheat Fagopyrum esculentum 179 179 A H H M L H H L L
4 Field Pea Pisum sativum 171 171 A H H M L H H M L
5 White Mustard Sinapis alba 21 21 A H H L L M H M L
6 Buffalo Grass Bouteloua dactyloides 150 150 P L-late L L L L L H H
7 Phacelia Phacelia tanacetifolia 27 27 A H-early L L L L H M L
8 Turnip Brassica rapa subsp. Rapa 15 15 A H H H L H L L H
9 Spring Lentil Lens culinaris 103 103 A H-early H H M H H H L
Inter-row
1 Crested Wheatgrass + Pubescent WheatgrassAgropyron cristatum + Thinopyrum intermedium14+15 10+13 P+P L L L L L L H H
2 Indian Ricegrass+ Buckwehat Oryzopsis hymenoides+Fagopyrum esculentum18+41 16+22 P+A H H M M H H L L
3 Blue grama Bouteloua gracilis 8 6 P L L L L L L H H
4 Western Wheatgrass Pascopyrum smithii (Rydb.) A. Love 27 18 P L L L L L L H H
5 Tall Fescue+Red Fescue+Sheep FescueFestuca arundinacea+Festuca rubra+Festuca ovina19+11+4 12+5+2 P+P+P H-late L H M H L H H
6 Perennial Ryegrass+Tillage RadishLolium perenne+Raphanus sativus 24+18 22+4 P+A H (early for Radish and late for Ryegrass)H H M H H radish L H
7 Canada Blue Grass Poa compressa 2 2 P L L L L L L H H
8 Balansa Clover Trifolium michelianum Savi 5 5 A M L M M L L L M
9 Berseem Clover Trifolium alexandrinum 18 19 A H-Early H H M H L L L
10 Persian Clover Trifolium resupinatum 4 3 A M-late L M L L L L L
11 Crimson Clover Trifolium incarnatum 24 18 A H-Early H H M H H L L
12 Alsike Clover Trifolium hybridum 5 4 A M-Late L M M M L L M
13 Birdsfoot Trifoile +Western WheatgrassLotus cornicalatus+Pascopyrum smithii (Rydb.) A. Love5+27 5+9 A+P L L L L L L H L
14 Hairy Vetch+Cereal Rye Vicia villosa+Secale cereale 30+60 18+51 A+A H-Early H H H H L M H
15 Field Pea+Cereal Rye Pisum sativum+Secale cereale 56+60 51+51 A+A H-Early H H M H H M H only Rye
Seeding rate (kg ha-
1)
27

Summary and Future Research
• Selection criteria: seeds availability and cost, establishment, dry
biomass, growth rate, canopy cover, weed suppression, height, host
for pest and diseases, maturity date, drought tolerance, traffic
tolerance, and risk of being invasive;
• Superior species were Ladino white clover and spring lentil for under
vine, and ryegrass, fescue, cereal rye, tillage radish, vetch and
berseem clover for alleyways; and,
• Field studies are planned to assess the effect of the superior cover
crop species on soil ecology, yield, and fruit quality/composition in
the next three years.
28

Acknowledgements
• Carbon dynamics experiment was managed by Seanna Zintel (Uvic Co-op); Molecular biology analyses
was performed by Dr. Lori Phillips (Harrow Research and Development Centre, ON)
• Grape block was established and maintained from 2011 to 2016 by Dr. Gerry Neilsen, Dr. Denise
Neilsen, Dr. Kirsten Hannam, Dr. Tom Forge, Shawn Kuchta and Stivan Losso;
• Technical support provided by Bill Rabie, Lana Fukumoto, Michelle Jones, Christina Holtjer, Emma
Regush, Annika Brickwood, Cory Berekoff, Abdessamad Nahli, Amanda Kruger and SuRDC Farm Services
crew.
29