Composting mimics nature by using the process of natural decomposition to add elements needed for plant growth to soil. The trick is to maximize that process, while avoiding its unpleasant effects. Compost is good—garbage heaps and rotting food are not.
A well-made organic compost contains the necessary minerals and elements because it is made of living natural materials. The N for organic compost comes from manures and green living material. Fresh manure has to be consumed and digested by bacteria. Those bacteria eventually die and are consumed by other forms of bacteria. After everything is broken down, the quality of the compost can be increased by leaving it for six additional months and allowing fungal networks to become established.
Bacteria need to have food, water and oxygen, just like any other living thing. Their food is carbon-based, like wood chips or grass. The farm purchases wood chips from local logging companies and also harvests its own "green chop," or fresh-cut hay, to mix into the compost. The micro critters chow down and things really start heating up. That is why a compost row needs to be turned regularly, or the microbes will be killed by the heat. A big step in the compost operation at Nash's was the purchase of a commercial compost turner from HCL Machine Works, which takes what's getting hot in the center and pulls it to the outside. All compost needs to reach 125-145 degrees for several days. If it gets too hot, water is added.
Nash's compost operation is state-of-the-art for a farm our size. We utilize a wind row (elongated pyramid shape) pile system on about eight acres on the Delta Farm as opposed to piles that would be turned or aerated individually. We begin building the piles with around 50 truck loads of wood chips from a local supplier. These are dumped in continuous rows and vegetable waste is added. The compost turner forms the wind rows, adds water/manure wash, and aerates the rows. Whey from a local cheese-making operation is also added to the wind rows to feed the beneficial bacteria and accelerate the decomposition process. A 4-wheel drive, tandem rear-wheeled tractor pulls the compost turner, and a coiled 3" flexible hose reel feeds water out to the turner at the crawler speed it requires as it moves down each wind row.
To meet organic certification standards, we maintain pile temperatures between 131°F and 170°F for 15 days, during which time the materials are turned a minimum of five times. This kills harmful bacteria and weed seeds. We exceed the 15 day requirement until most of the wood chips are decomposed. Otherwise the material applied to our fields would require additional nitrogen to finish decomposing. This would remove nitrogen from our soil instead of adding it, defeating the purpose of composting.
Composts that don't meet the above criteria can still be used in organic farming. But if they contain animal manure, they must be applied to agricultural land in accordance with USDA National Organic Program regulations for manure which state that raw animal manure must be composted, unless at least one of the following conditions is satisfied:
||It is applied to land used for a crop not intended for human consumption.
||It is incorporated into the soil not less than 120 days prior to the harvest of a product whose edible portion has direct contact with the soil surface or soil particles.
||It is incorporated into the soil not less than 90 days prior to the harvest of a product whose edible portion does not have direct contact with the soil surface or soil particles.
We keep thorough records so that we know when each component is added to the wind rows, when the piles are turned, and what the temperatures are.
The finished compost is loaded into a compost spreader and applied to our fields, or the remaining wood chips can be screened out of the compost leaving a wonderful soil base for seed starts in our greenhouses.
Mixed with soil, compost provides virtually all of the essential nutrients for healthy plant and bacterial growth, and it releases those nutrients slowly over time. It also improves soil structure, making it easier to hold and use the right amount of moisture and air, and it improves plant vigor and disease resistance.