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Organic Amendments & Cover Crops Can Enhance Yield Stability & Agricultural Resilience in Canadian Vineyards - Mehdi Sharifi, AAFC

Grape growers are increasingly interested in management practices that enhance long-term productivity while improving the ecosystem health. Optimizing the agroecosystem in a way that the soil remains healthy and fertile leading to grape productivity and quality is challenging, especially with concern coming from climate change and possibilities of increased extreme weather events such as droughts. Organic amendments and cover crops are two management practices that can enhance the health and resilience of the vineyards. Organic amendments contain soluble organic carbon (C) that can be easily transported down the soil profile, and modify soil microbiome, and C cycling. Vertical distribution of soluble C in the soil profile can have an implication in soil and plant health management and consequently affect the resilience of vineyards. In order to encourage a wider adoption of cover crops in vineyards, research must introduce suitable CC species for each region and develop management practices that address trade-offs between provided services and competition for resources need. With climate change and the need to adapt to climate uncertainties (e.g. droughts, heavy rainfall), cover crops can represent a great opportunity to buffer against these uncertainties. Results of two regional projects on surface applied amendments and cover crops will be presented.

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Organic Amendments & Cover Crops Can Enhance Yield Stability & Agricultural Resilience in Canadian Vineyards - Mehdi Sharifi, AAFC

  1. 1. Organic amendments and cover crops can enhance yield stability and agricultural resilience in Canadian vineyards Mehdi Sharifi Summerland Research and Development Centre 1
  2. 2. 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
  3. 3. 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
  4. 4. 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
  5. 5. 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
  6. 6. 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
  7. 7. 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
  8. 8. Maintenance and Harvest 8
  9. 9. 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)
  10. 10. 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
  11. 11. 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
  12. 12. 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
  13. 13. Results: Yield stability and reliability 13
  14. 14. 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
  15. 15. The high C surface applied material modifies soil C down the soil profile Interactions ** Amendment ***; Depth *** Total C/DOC ratio= 1750:1 15
  16. 16. 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
  17. 17. 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
  18. 18. Screening Cover Crop Species for Okanagan Valley Vineyards 18
  19. 19. 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
  20. 20. 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
  21. 21. P85- Tillage Radish + Perennial RyegrassP79- Ricegrass + Buckwheat 21
  22. 22. P92- Crimson clover P93- Cereal rye + Hairy vetch 22
  23. 23. 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
  24. 24. Ladino clover Buckwheat 24
  25. 25. Turnip Phacelia 25
  26. 26. Winfred Brassica Spring Lentil 26
  27. 27. 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
  28. 28. 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
  29. 29. 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

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