manure vs compost

The process begins with the collection of horse stable waste. This material generally has the correct carbon to nitrogen ratio for thermophilic composting. The moisture content of the material is adjusted to 60%. Then it is mixed and fluffed to improve porosity and placed in a 10 cubic yard concrete cell.

The air we breathe is 21% oxygen. If we were to hold our breath, we would quickly consume the oxygen in our system. The same thing is true of a compost pile. If we do not add air, the oxygen level drops to anaerobic conditions within minutes. The most common commercial method of composting is turned windrow. As there is no method of turning alone that can overcome the oxygen consumption rate and prevent anaerobic biology to prevail, at Fern Hill Compost, we use covered aerobic static pile composting in order to maintain oxygen levels in the feed stock. With aerobic composting, the main by-products are CO2, water, and heat.

Advantages of this method include:

• Pile temperature and moisture content control

• Pathogens and weed seeds elimination

• Vaccine, antibiotic and pesticide degradation

• Composting process cycle time decrease

• Superior quality compost production.

Our equipment includes a system to deliver air to a plenum underneath each composting cell and to the feed stock it contains. Controlled by pile temperature, timers, and delivery valves, the proper oxygen level is maintained 24/7 throughout the 30 day stage 1 composting process.

Temperatures are recorded from multiple sample points within the pile to assure uniformity and that pasteurizing conditions are attained. Typical temperatures will run as high as 160 degrees F, remain above 131F for a minimum of three days, and then drop into the 100F – 110F range. These temperatures are sufficient to kill pathogens and weed seeds, but not the beneficial microbes we count on to perform the decomposition of the organic material.

Each composting cell has a water addition system to adjust moisture level in the feed stock, as well as a leachate collection system in the floor to allow any liquid that drains out of the pile to be returned to the cell, rather than leaching to the environment.

Every 7-10 days during the active stage of composting, the material is removed, remixed, and placed in another cell, where thermophilic temperatures are once again maintained.

After stage 1, the material is moved to a curing building for stage 2 composting. The material is stored for a minimum of two months in order to properly cure. At all stages, the material is under roof, and never is exposed to rain which would leach away nutrients. In-house testing is done to assure a stable and mature product prior to packaging.

Bulk Density                                           809 lbs/yd3

Moisture content                                   54.4%

pH                                                              6.96

Conductivity (salinity)                            6.9

Total Nitrogen                                          1.63%

Phosphorous                                            0.22%

Potassium                                                  1.89%

Organic Matter                                          62.8%

Carbon:Nitrogen Ratio                            20.8

Solvita CO2   (Range 1-8)                         7.29

Solvita Ammonia (NH3)  (Range 1-5)   5.00

Solvita CO2 Concentration                    0.62%

While all animal manures are good sources of organic matter and nutrients, it’s impossible to make a precise analysis, because nutrient values vary greatly depending on the diet and age of the animals, and the nature and quantity of bedding in the mix. For example, manure with straw or sawdust will have a different nitrogen composition than pure manure. But it’s useful to know whether the manure you’re using is rich or poor in a particular nutrient such as nitrogen.

Also please don’t be misled by the N-P-K numbers that suggest manure is less powerful than chemical fertilizers. Composted manure is actually far better because it contains large amounts of organic matter, so it feeds and builds the soil while it nourishes the plants. Slow-release nutrition is best. This is one of the primary ways that organic fertilizers have an advantage over chemical ones.

The values of manure and organic fertilizers in general, are often based on the relative amount of nitrogen (N), phosphoric acid (P) and potash (K) they contain. A direct comparison of manure, composted manure, and chemical fertilizers based on these numbers is not valid, or at the least, is misleading. But, for the record, Dairy cow manure will have typical N-P-K values of 0.25 – 0.15 – 0.25, and horse manure will have typical N-P-K values of 0.70 – 0.30 – 0.60.

One of the largest concerns with using yard waste as feedstock for composting is the high residuals of pesticides as well as other contaminants contained in these curbside piles of leaves, grass clippings, brush, and other garden residues collected by municipalities. At this time, little is known about the biological degradation and residual levels of pesticides this material may contain. A key factor in this degradation, however would be the composting method. For example, at best, municipalities will typically utilize a turned windrow method. At worst these piles are left as unturned piles for two years or more, and never achieve thermophilic temperatures which would break down some of these undesirable compounds.

Commercial mushrooms grow in a specially formulated and processed compost made from wheat straw, hay, corn cobs, cotton seed hulls, gypsum and chicken manure. The 3 to 4 week long composting period is closely supervised and managed to assure that the composting temperatures exceed 160°F for a few days in addition to a steam pasteurization which occurs about one week before mushroom spawn is mixed with the compost. Finally, a layer of sphagnum peat moss mixed with ground limestone is top dressed onto the compost, and mushrooms grow on the peat. When the harvest if finished, farmers steam pasteurize everything in the growing room and dispose of the peat moss and compost that remain.

Research into using this material as a substitute for peat moss or other organic material in commercial nursery production systems have had to use a regular feeding system because the nutrient levels are too low to produce a crop. There is also a high salt level in most spent mushroom compost that has to be leached out before the crop is planted. General analysis of nutrient levels are negligible. You will not get a major nutrient benefit from this material. Regarding chemical residues, mushroom farmers have major problems with flies and fungus gnats in their growing facilities and spray regularly with such products as methoprene, cyromazine and diflubenzuron, Dimlin and Diazanon. There are also fungal infections that can wipe out a mushroom crop and require control by such chemicals as benomyl, thiabendazole and chlorothalonil. Naturally, if treated with any chemicals or having used any kind of artificial nutrient to create a composting action, mushroom compost will not qualify for use on certified organic farms.