Practical Silvopasture Implementation: A study of the ecological, nutrition, and food system impacts of crop-livestock integration

Commodities

• Fruits: apples
• Animals: ducks

Practices

• Animal Production: grazing - rotational
• Crop Production: agroforestry, silvopasture

We have chosen to allow our ducks to rotationally graze in our apple orchards to receive the benefits of Silvopasture (for both animal and prevailing fruit crops) while maintaining food safety.  Our farm has worked with the Henderson County
Extension Service Small Fruit and Vegetable Agent and Livestock Agents, as well as the Area Specialized Agent for Fresh Produce Food Safety in Western North Carolina.  Together we developed a rotational grazing plan that takes advantage of
off-season and post-harvest land.  This plan follows the 90-120-Day Rule for Organic Crop Manure Amendment from USDA that states raw animal manure must be applied 90 days prior to harvest of the tree crop and 120 days to any crop that comes in contact with the ground.⁸ 

Silvopasturing duck in orchards is not only possible but also a valuable market opportunity for farmers to diversify their
product line while reducing costs of commercial fertilize, pesticides, and application labor.  According to the USDA, a
farmer can economically manage weeds without herbicides using silvopasture.  These pastured animals compete with weed beds for water, nutrients, and sunlight, thereby enhancing tree growth and reducing weed pressure.¹⁵ The economic
value of many conventional fertilization schedules is in excess of $10,000.  The value of manure is approximately
$0.50/pound but could be double this value considering the economic worth of improved soil structure, diversity, and
activity of soil organisms that conventional fertilizers do not provide.¹⁶ Fertilize costs have increased substantially over the past decade and silvopasture is an effective means to reduce or eliminate these costs.  Silvopastures create biological diversity and improve water and soil quality; resulting in improved crop output and quality. Perennial forage protects the soil from water and wind erosion and adds organic matter to the soil.  Additionally, ducks are able to forage extensively and can decrease feed costs by as much as 30%.

We have selected the Silver Appleyard Duck breed for our farm because they are one of the best egg-layers in their class and are excellent foragers with superb mothering skills.  Appleyards have a lower saturated fat content than other duck
breeds, providing lean meat that is prized by chefs for its gourmet roasting ability.  Silver Appleyards were developed
in the 1940s by Reginald Appleyard in England.  He created the Appleyard as a prolific layer that also has size and large
breasts for meat, making it the ideal all-purpose duck. Ducks yield 74% of their weight as marketable, making this bird more valuable than other processed poultry. Silver Appleyards came to the United States in the 1960s, but were not available to the public until 1984, by 2000, The American Poultry Association accepted the Silver Appleyard into the Standard of Perfection.  Today, Appleyards are listed on the Conservation Priority List and are in danger of becoming
threatened in the United States.  We are proud to raise this heritage livestock breed and improve market demand for heritage livestock products. ^5,7

Customers are requesting regenerative practices and are going beyond organic, recognizing the impact farm practices have on our food system.  This model of silvopasture can also serve as a community-connection opportunity and result in increased sales outlets to holistic and local supermarkets.  And as farmland in Western North Carolina and across the United States dwindles, it is important now, more than ever, for farmers to increase per-acre revenue and market viability.

The Silver Appleyard Ducks will serve a dual purpose: as a high-quality, nutritious marketable product, as well as improve
our orchard management practices.  Duck manure has a balanced NPK ratio at 2.8:2.3:1.7 while chickens provide only
1.5:0.5:0.8.  Not only do ducks provide a higher percent of primary macronutrients in a more balanced ratio; but they also
provide a larger volume that is in a form more readily available for plant uptake than chicken manure.^14-15

Most study designs related to manure application measure the litter nutrient content rather than its direct impact on the soil quality and prevailing ability to minimize chemical input.  In this study, we aim to show statistically significant improvements in pest prevalence, weed pressure, and/or soil composition.

Our research uses a paired comparison design and t-test statistical analysis. We have treatment blocks and control
blocks, approximately 2.3 acres in size.  Each block contains two plots, one plot of each treatment (treatment and
control), blocks are replicated four to six times across the field to account for field fertility gradient, and as recommended
by Sustainable Agriculture Research & Education.¹⁷

The treatment will include a 6-month rotational grazing pattern for Silver Appleyard ducks at a rate of 30-50 ducks/acre in
treatment blocks.  Assessments are completed at Baseline, 3 months post-treatment, 6 months post-treatment, and 1 year
post-treatment.  Multiple assessment types and repetitions are required for this research as soil nutrition and composition
naturally vary within a field and throughout the course of a season.  Our assessments include the Pest Prevalence Assessment, USDA’s In-Field Soil Health Field Assessment, and NCDA&CS Agronomic Division Soil Testing Section’s Comprehensive Soil Health Laboratory Test, Heavy Metal Analysis, and the Diagnostic Problem Sample Laboratory Test as needed.  We additionally collect subjective data including field notes and images.^18-19

Research Question

Is silvopastured duck an effective and practical method of pest, weed, and soil nutrient management in fruit and nut orchards?

1. Can adding silvopastured duck to fruit orchard management
   system:
   1. Reduce pest pressure/prevalence?
   2. Reduce weed pressure
   3. Improve soil microbiome?
      1. Are any of these changes significant enough to reduce
         or eliminate chemical input?
         1. If so, to what extent?

Hypothesis

The addition of silvopastured duck in fruit tree management will result in a statistically and financially significant improvement in one or more of the following:

1. Pest prevalence/pressure
2. Weed pressure
3. Soil microbiome

Objectives

1. Introduce Silvopastured duck into fruit orchard on test plots
   of approximately 2.3 acres for a 6-month rotational grazing
   pattern.
2. Collect and analyze data using Pest Prevalence
   Assessment, In-Field Soil Health Assessment, and
   Comprehensive Soil Health Laboratory Testing at
   baseline, 3-months post-treatment, 6-months post-treatment, and
   12-months post-treatment.
3. Analyze and disseminate results widely in the agriculture and
   healthcare fields.

 Data collection methods

1. Pest Prevalence/pressure

Pest trapping and monitoring is a method of quantitative data collection as recommended in Integrated Pest Management Systems (IPM).  This is conducted by our professional Pest Scout, R. Jordan, who uses a variety of adhesive and pheromone-exuding traps.  Our Pest Scout then uses insect counts, action thresholds, and degree-day models to generate a report of pest prevalence and recommended control solutions.  Our Pest Scout will collect and disseminate this data to our farm throughout the data collection period and, ideally, at least one calendar year thereafter. These traps will be set during the tight cluster apple-growth stage and hung approximately 6 feet. off the ground.  Traps are positioned at the interior of the orchard and kept at least 20 feet apart from each other.

The specific pest species we target will determine the type of trap and pheromone lures selected.  We use both Delta-style
and wing traps to monitor Codling moths, Oriental fruit moths, and Leaf-Roller Species (tufted apple bud moth, red-banded leafroller, oblique-banded leafroller, and the lesser appleworm) in our orchard.

Below are the trap and pheromone lures used, as recommended by NC
State University:

• Codling moths Delta-style traps with replaceable interior
  sticky liners and Codling Moth L2 pheromone lures
• Oriental Fruit Moths: Delta-style traps with replaceable
  interior sticky liners and Oriental Fruit Moth L2 pheromone lure
• Leaf-Roller Species (tufted apple bud moth, red-banded
  leafroller, oblique banded leafroller, and the lesser appleworm);
  Wing traps instead of Delta traps, which is a more cost-effective
  option for these. These traps consist of a plastic top, a sticky
  cardboard bottom, and a wire frame holding the two together with
  the applicable pheromone lure.²⁰

     2. Soil microbiome

Soil microbiome will be evaluated using both quantitative and qualitative data collected in conjunction with NC State
Extension, Small Fruit, and Vegetable Agent and encompass chemical, biological, and physical properties.  We collect subjective data regarding crop performance, perform a quantitative Comprehensive Soil Health Laboratory Test,
and use the USDA Nature Resource Conservation Service (NRCS) Crop Land
In-Field Soil Health Assessment that evaluates:

• • Soil cover
  • Residue breakdown
  • Surface crusting
  • Ponding/infiltration
  • Penetration Resistance
  • Water-Stable Aggregates
  • Soil Structure
  • Soil Color
  • Plant Root Development
  • Biological Diversity
  • Biopores

We follow collection and sampling guidelines as indicated and directed by NRCS and are available for full review
here.¹⁸

The Comprehensive Soil Health Laboratory Test (form AD-12) is completed in conjunction with the North Carolina
NCDA&CS Agronomic Division Soil Testing Section and approved by the Soil Testing Section Chief.  Samples are collected
and analyzed for nutrient composition.  We complete a baseline Heavy Metal Analysis (Form AD-13) and follow up with subsequent analysis as needed. Form AD-2 we use for diagnostic problem samples, as needed. Lastly, we collect subjective data regarding general crop performance, visual nutrient deficiency symptoms, and field images.³