Orchard Composting Project
This project aims to work with an apple orchard that produces apples for cider
production. The orchard generates 170,000 pounds of apple pomace over a fourmonth period. They also generate approximately 100,00 pounds of tree prunings
per year. The owner is interested in composting the apple pomace and tree
prunings so that they can use the compost to improve the soil in their orchards.
The goal of the project would be to evaluate two different methods of on-farm
composting and to evaluate use of finished compost in soil fertility management.
We have tentatively developed a recipe for compost that would include pomace,
poultry litter and tree prunings. The orchard will need to import the poultry litter to
supply nitrogen to achieve the proper carbon to nitrogen ratio for composting
(approximately 30:1). We will mix raw ingredients (feedstocks) and build
compost piles in early September. We will compare a passively aerated windrow
system (PAWS) versus a windrow turned system of composting. The PAWS
method requires thorough mixing of feedstocks either in a feed mixer or a
manure spreader. The mixed materials are then deposited onto a bed of
perforated PVC pipes and covered with a 6”-layer of finished compost (we will
need to purchase finished compost for the first year since we won’t have any on
hand). The pile is aerated passively by promoting convective air flow through the
perforated pipes into the warm compost pile. This method does not require any
turning or mixing once the pile is set up. The moisture content will have to be
adjusted towards the wet end of desirable (close to 65-70% by weight) because
moisture will be given off as water vapor during the active phase of composting,
and you can’t add water to PAWS piles during the composting process. The
other method will involve turning piles on a weekly (for the first 3-4 weeks) and
then biweekly (until the air temperature drops to 35oF) using a front end loader.
Piles can be watered when turned using this method. We may need to purchase
compost covers to cover piles during the winter and when piles are curing.
Curing piles have lower temperatures, and weed seeds might get deposited onto
curing piles and become an ideal medium for germination.
We will monitor temperature, air quality (carbon dioxide production or oxygen
consumption), and pile moisture contents on a weekly basis. We will also
determine the time and labor required to set up and manage compost piles using
these two different methods. We will evaluate the quality of the finished compost
the following spring prior to application around apple trees. Quality
measurements will include a test for biological stability, C:N ratio of finished
compost, available nutrients, ash content (determines non-organic material), pH
and soluble salts.
Budget Request: $5000
Item
Equipment Rental for composting
PVC pipe and other materials for
composting
Equipment for monitoring composting
process (temperature probes, O2-CO2
meter, compost maturity kit, etc.)
Lab analyses of finished compost
Travel
Stipend to farmer
Total
$ Amount
1000
1000
1000
400
400
1200
5000