Utilization of municipal composts in commercial horticulture

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Morris Ross
5 years ago
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Zebarth (& lots of technical assistance) Pacific Agri-Food

1 Utilization of municipal composts in commercial horticulture Tom Forge Gerry Neilsen, Denise Neilsen, Kirsten Hannam, Bernie Zebarth (& lots of technical assistance) Pacific Agri-Food Research Centre Summerland, BC Compost Council of Canada Summerland, March 2, 2016

crops and green manures On-farm compost minor Off-farm sources Animal manures regionally significant

2 Soil-nutrient management in commercial horticulture Growers recognize importance of organic matter inputs, but Primarily fertilizer-based nutrition Soil organic matter managed primarily via: Cover crops and green manures On-farm compost minor Off-farm sources Animal manures regionally significant Livestock manure compost a little, but growing Municipal compost very little, but growing Woodwaste mulch no N

3 Barriers to adoption: contaminant concerns Current perceptions of muncipal compost strongly influenced by historical association of biosolids with municipal compost Human pathogens Heavy metals/trace elements Herbicide residues Organic contaminants Antibiotic residues Education, education, education

Organic Matter Recycling Regulation of BC Pathogen reduction similar to CCME/CFIA Trace elements slightly more

4 Education Composts for sale are regulated unlike manures e.g. Organic Matter Recycling Regulation of BC Pathogen reduction similar to CCME/CFIA Trace elements slightly more restrictive than CCME/CFIA Vector attraction (maturity): Aerobic process for >14 days at 40 C or higher (45 C average) C/N ratio between 15 and 35 Curing for at least 21 days and must not re-heat under spec. conditions CFIA Trade Memorandum T (Fertilizers Act and Regulations)

5 Market-driven guidelines on biosolids and composts Education re. actual quality of biosolids compost may not be enough CanadaGAP, EuroGAP Certification important for market access Independent of government policy or reg s Biosolids not allowed Compost with biosolids as a feedstock? Vague language Undermines value of all commercial composts

6 Organic horticulture unique opportunity? Need the nutrients, especially nitrogen, more than commercial horticulture Growers often use high-grade expensive organic N fertilizers, e.g. Fish emulsion Feather meal Pelletized poultry manure Alfalfa meal, soy meal Guano Bone meal Blood meal Kelp meal But organic sector more sensitive to contaminant concerns

7 It may be safe, but is it beneficial for production? The role for CQA Ensures adequate testing for some properties of agronomic significance Recommended uses broadly defined Horticulture may span different CQA categories Use ph C/N Moisture Part. size EC %Na Remediation NA <2 inch <20 <3% Soil Amendment NA <1/2 inch <6 <2% Landscaping <50% <1/2 inch <5 <2% Planting media <50% <1/2 inch <4 <2% Turf topdress <50% <3/8 inch <3 <1% Potting soil <50% <1/4 inch <3 <1%

Costs vs-benefits Compost is an expensive input for commercial growers Value is context dependent: Different production systems Compost can t compete with

8 Costs vs-benefits Compost is an expensive input for commercial growers Value is context dependent: Different production systems Compost can t compete with fertilizer 100 kg N from urea = $160 At 1.5% N, 6.7 Mg compost needed for 100 kg TOTAL N = $330 Are the other benefits of 2.8 Mg organic matter worth $170 per hectare?

9 Compost NPK Knowledge of N content, C/N ratio and PAN are key for use in commercial horticulture CQA Difficult to use as primary source of NPK P & K accumulation High-N compost can be desirable Apply as amendment, but still need to know N value In long term, soil health benefits may reduce nutrient requirements

10 Costs vs-benefits Can soil health benefits be made tangible? Disease suppression adequate to reduce fungicide requirements? Drought tolerance value of reduced irrigation? Quantify yield increases beyond NPK? Carbon sequestration credits?...the future gamechanger?

has involved incorporation of compost into potting media or seed beds Disease suppression when surface applied and/or

11 Benefits to soil health & productivity: disease suppression Demonstrated for Rhizoctonia, Pythium, Phytophthora, Fusarium, Verticillium diseases Related to changes in rhizosphere microbial activity not biofumigation Most research has involved incorporation of compost into potting media or seed beds Disease suppression when surface applied and/or at modest rates under field conditions? Different from other amendments, manures? Suppression of plant-parasitic nematodes?

12 Benefits to soil health and productivity: nematode suppression Induced natural biological control Hypothesis: Enhanced soil biological activity, diversity and FW structure leads to regulation

13 Benefits to soil health and productivity: Soil-plant-water relations Improved WHC Organic matter Biogenic changes in soil structure Improved plant water stress tolerance Improved root growth Pathogen suppression Improved rhizosphere interactions, e.g. AMF

not as critical Foreign matter is visible High N

14 Utilization in commercial horticulture 1: Surface application to established crops Quality wrt salts, etc. not as critical Foreign matter is visible High N availability may be desirable How to predict PAN? Benefits may take long time to accrue

application + tillage Alfalfa hay mulch Bark mulch/5-year compost Plastic mulch/5-year compost

15 Apple Multiple studies since 1994 Ogogrow x shredded paper mulch interaction (2 experiments) Biosolids x shredded paper mulch interaction Organic soil management practices Annual compost application + tillage Alfalfa hay mulch Bark mulch/5-year compost Plastic mulch/5-year compost Soil properties improved Up to 60% in increase in yield (ogogrow + SP) 30 Mg/ha (~150 kg PAN/ha) orchard basis

Winegrape Merlot/SO4 planted 2011 Whole-plot (row)

Compost ~20 Mg/ha (~200 kg TN/ha) in 2011, 2012, 2013 N

mulch/compost SOM & POXC increased by compost at depth,

16 Winegrape Merlot/SO4 planted 2011 Whole-plot (row) treatments Microsprinkler vs drip Subplot treatments Compost ~20 Mg/ha (~200 kg TN/ha) in 2011, 2012, 2013 N fertigated Bark mulch/n fertigated NPKB fertigated Bark mulch/compost SOM & POXC increased by compost at depth, but No effects of compost on: Nematode populations Plant growth

Interaction with irrigation type Measured: growth-yield, fruit quality Soil

17 Organic winegrape Mission Hill Vineyards Variable types of compost Harvest Power GlenGrow Bighorn (beef feedlot + grape marc) 10 Mg/ha 2013 & 2014 Interaction with irrigation type Measured: growth-yield, fruit quality Soil health indicators Parasitic nematode populations No effects of compost observed

18 Sweet cherry FAIP project: UBC-Okanagan Melanie Jones, Louise Nelson Tanja Vogel, Paige Munroe Can compost mulch reduce water stress? Whole-plot (row) treatments Post-harvest deficit irrigation or not Subplot treatments Compost mulch (GlenGrow) Bark mulch

pathogen complex Abiotic factors contribute Limited P availability

19 Compost utilization in commercial horticulture 2: Replant site remediation Replant disease complex: Biotic component Pratylenchus penetrans Fungal pathogen complex Abiotic factors contribute Limited P availability Compaction, etc. Fumigation has been control method of choice Alternative practices needed

20 A soil health perspective on replant stress management A complex problem with no clear single cause Integrated-multifaceted approach to management Requiring multidisciplinary research Can we suppress pathogens without fumigants? passive OM compost NH 4 + NO 3 - PO 4 - mulch nematodes Enhanced Soil food web and soil health Can we optimize root growth despite pathogens? Fungal pathogens Litter, manure active OM

Salts are important Potential for excessive N mineralization important When to begin

21 Compost utilization in commercial horticulture 2: Replant site remediation ~50 Mg/ha to treated row area High application rates desirable to achieve disease suppression: Salts are important Potential for excessive N mineralization important When to begin fertilizing again? Growers might be more inclined to pay for higher quality material

Summary Barriers to utilization Lingering concerns about contaminants Education Improved source separation and composting practices CQA, etc.

22 Summary Barriers to utilization Lingering concerns about contaminants Education Improved source separation and composting practices CQA, etc. has important role Costs vs Benefits to commercial production systems Long-term research to demonstrate benefits to production Difficult to do on many materials Modes of utilization Top-dressing Benefits may take long time to accrue Quality wrt salts, etc. not as critical Foreign matter is visible High N availability may be desirable Preplant incorporation High application rates desirable one-time opportunity Low salts and low N mineralization potential important Research needed to demonstrate consistency

Non-fumigant options for replant disease/nematode management

Non-fumigant options for replant disease/nematode management OSU Replant Discussion March 17, 2017 Tom Forge Replant management for cherry Soil factors causing poor establishment of replanted fields/orchards