1.     The compost will continue to breakdown to a humus rich substance, feeding beneficial micro-organisms in the soil and enhancing the “soil food web”.

2.     The organic acids in the compost will help mobilize the soil particles, causing them to form aggregates called “soil peds”.  rent a car bulgariaThis has the effect of loosing the soil (i.e., increasing soil porosity) and enhancing infiltration and moisture retention during the low rainfall months. 

3.     This loosening effect also enables plant roots to reach further down into the soil, resulting in healthier plants along with decreased soil erosion.

4.     As the soil begins to warm up again next spring, the soil biology will come alive, the nutrients in the compost will be released and the plants will thrive.  [Note: Spring is the worst time to get back on the pasture with farm equipment because of the likelihood of soil compaction. If you spread the compost in the fall, the job will already be done and you will not run this risk.

5.     This strategy also applies to spreading compost in your landscape areas and vegetable garden. 

I recently took a trailer load of 60-day old horse manure compost to our family friends’ home for use in their garden - and as an experiment, we screened the mix on a ½-inch screen.  It took approximately 45 minutes for us to screen two cubic yards and to move the coarse and fine fractions with a wheel barrow to respective holding piles in the back yard. 

What we learned is that the ½-inch plus “lumps and bumps” comprised about 1/3 of the total volume and that the remaining 2/3 was mostly fine wood particles.  My operating theory is that the majority of the nutrients are contained in the “lumps and bumps” and so I suggested tilling this material into their vegetable garden and spreading around the base of their landscaping plants.  In turn, I suggested that the fines be used as a mulch or weed barrier in their landscaping.  I will be doing laboratory testing on these two fractions this winter to learn more about how they differ in nutrient value.

My Response:
As I understand it from several of our veterinarian clients, a horse’s digestive system is only 17% to 20% efficient. Consequently, much of the hay passes through the gut and the manure has a very high cellulose content. Cellulose is resilient to biologic decomposition and therefore, even after composting, the manure balls will retain some of their structure resulting in a lumpy and bumpy compost. If you break into one of these lumps, you will see that it is dark throughout and is no longer manure. Often, it also has white specks throughout – these are Actinomycetes, a type of fungi that is working to break down the residual cellulose. This is also true of loose hay as well as straw used for bedding.

Bagged potting mix of every variety has been screened (and typically blended with other products), resulting in a uniform texture. This look and texture can be accomplished with your compost in one of four ways:

1. If you use a pasture vacuum, the manure balls will be macerated as they are drawn past the impeller, thus resulting in a uniform texture going into the compost system. By providing a fine texture material at this point, your composting time will also decrease significantly. We are in conversation with Greystone Pasture Vacs adn considering a working relationship to offer discounts when both a Greystone Pasture Vac and an O2Compost Training Program are purchased.
2. Following composting, you can screen the mix. I have built a 3-foot by 8-foot screen using 2″ x 4″s and hardware mesh, and it works quite well. Putting the screen on a ~30 degree slope, I toss some compost at the top end and then separate the fine material (”fines”) from the coarse material (”overs”) using a wide push broom. The broom is gentle on the hardware mesh and keeps the screen openings free of compost build-up. Note that drier compost is easier to screen.I place the screen overs (i.e., the lumps and bumps) around my landscaping plants (rhodendrons, azaleas and evergreens) - this is where the majority of the nutrients reside. I then use the fines as mulch layer between the plants as a weed barrier. This is somewhat labor intensive but it makes a great job for youngsters who want to make a few dollars. In fact, selling the screened compost (both fines and overs) in bags can yield a very nice income stream for teenagers. If this is of interest to you, please listen to the audio testimonial by Robert Garofalo.
3. Some of our clients take their finished compost and run it through a garden-sized limb shredder. This, no doubt, is also somewhat labor intensive but it reduces all of the lumps and bumps into a uniform fine texture. Many of these clients are using the shredded compost back in the stall as bedding. You can also combine screening with shredding of the coarse materials to oprovie a superior potting media.
4. The last way to reduce the lumps and bumps is the easiest, but it also takes the longest. Placing the finished compost in a holding pile on soil will encourage earthworms to find it and do the hard work for you. It helps to tarp the pile and it is important to keep the pile very wet, almost saturated. This process usually takes 6 to 12 months but, if you are not in a hurry, it will not only reduce the lumps and bumps to a minimum, it will also produce a batch of worm castings that have magical properties. Ohio State University has done a considerable amount of research on the benefits of using work castings in greenhouse applications - add 10% to any bagged product to provide optimum growing conditions. Castings can also be sold in small buckets and bags for top dollar.

ANSWER:   It sounds like everything is going as planned. In general, heat results from the biologic activity during the first 21-30 days but the actual duration of heat generation is a function of the available carbon and the amount of nitrogen in the feedstocks. With horse manure composting, the readily available carbon - simple sugars, proteins, etc. - are utilized quickly leaving the more resilient forms of carbon (cellulose and lignin) to be degraded over time. As as result, the pile temperature tends to jump up quickly and then fall off in 3 to 4 weeks. This is referred to as the “active phase”.

Following the active phase, the compost pile transitions into what we call “curing’. While active composting is a bacterial-driven process, curing is a fungal-driven process and takes place at cooler temperatures. You should see mushrooms growing on top and a white fibrous material growing in the top 12-18 inches. This is called actinomycetes and it is a very good thing given that it is working on the cellulose in the manure balls and lignin in the bedding. To produce a truly stable product, curing can take 30-60 days following active composting.

The one thing to watch for is the moisture content of your mix. Pile temperatures will plummet if the moisture content drops much below 45%. The mix should fee wet to the touch and when you squeeze a handful, you should be able to get a drip or two or a bead of water between your fingers. To determine this, take a posthole digger and dig a vertical hole and see what the materials look like, to to bottom.

Also, when we meet the oxygen demand of the micro-organisms during the active phase, additional airflow will actually cool the pile down because we are displacing the hot air with cooler air. To increase the pile temperature, try reducing the airflow and see if the pile temperatures rebound at all. If your mix is wet and you don’t see a rebound, then you are likely in the curing phase.

Hi Peter… I’ve been doing some more reading on your system because I think it is a great concept for our stables. I have questions/concerns about our severe winters. Specifically, I’m wondering about: 77″ of snow thsi year and -40 degrees a couple days. It is very typical to have -0 nights and highs in the single digits for 2 months of winter. The ground is frozen fro 6 months out of the year.

Does frozen manure work in the system? Even our stall manure is frozen in the middle of winter. How do bays get “cleaned” in between batches? How long is the complete process from fresh to cured in 10 degree weather? Does the finished product freeze solid in the bay?

Peter’s Response to Jolene’s Email:

Jolene… This is an excellent set of questions. Up until a year ago, I wouldn’t be sure how to answer them however we’ve been working with a client in Morrisville Vermont who experienced these same conditions and we “redesigned” her system for extreme cold and this year all went quite well.

First, our systems use post and beam construction. For each bay, we place boards (e.g. tongue and groove 2 x 6’s) on each side of the posts to create double wall configuration. We then fill the hollow space with insulation. This can consist of foam board; spray-in, expandable foam; vermiculite pellets, etc. Finally, we place a 2 x 10 cap on top of the wall to seal in the material.

Second, we construct light weight, removable, insulated panels for the front to prevent excessive heat loss through the slide boards. These panels may be constructed using 2 x 2’s and thin plywood on each side (much like a hollow core door), again with insulation on the inside. We would use these panels only during the extreme cold periods.

Third, we place an insulated cover over the top of the bay when it is full. We have played with a vareity of designs, but a simple one consists of two layers of poly-tarp with flexible insulation sandwiched in between. We use grommets to create a single unit. This is light weight and easy to handle.

Finally, prior to filling the bay, we coil a 48-foot length of heat cable on the slatted floor (these are inexpensive and available on the internet through a variety of greenhouse suppliers). This acts just like a block heater for your car.

Operationally, you do your daily chores removing the manure and bedding from the barn and fililng the bay. Everything can be frozen solid - not a problem. When the bay is full, we plug in the heat cable and allow it to thaw out the core of the pile over a few days and once the core of the pile is up to 60 or 70 degrees (max for the heat cable), the biology will take over and bring the pile temperature up to the desired levels.

One key is to minimize aeration so that we don’t cool the pile excessively and, more importantly, so that we don’t dry out the material to the point where the biologic process crashes.

The second key is to not let the compost stay in the bay too long. Generally, the process is roughly 30 days long, but it is okay to cut it short so that we can remove the mostly-composted material from the bay before it returns to a frozen condition.

In designing the system, you may also consider over-sizing it somewhat so that you can receive the raw manure, compost it, and then allow it to cure / store in the same bay until the spring time. This obviously results in a larger system and will cost more, but it may also be worth the convenience of not having to move material when it is well below zero.

PM

“We have a 3-bin rotating system in which we normally have one bin in the composting phase and another in the curing phase. Our property has some slope to it, so that gave us the opportunity to put the bins up next to a retaining wall for easy loading. There is enough space in front of the bins to back a truck up for loading the finished compost.

We have found that your blower cycle recommendation seems to work well for aerating the pile. Once fully loaded and aerating, our bins reach abuot 160 degrees and stay there for about two weeks and then slowly drop thereafter. Active composting goes on for about four weeks and then the pile cures for four weeks before we disassemble the bin. I drilled a 3/8″ hole in the front of each bin as a port for the thermometer.

All in all, we are able to compost about 2/3 of our horses’ manure. Thanks for designing this system!”

I built three insulated bins that have an R factor of about 20 or so. This has been allowing us to keep our manure composting when the temperature hits single digits and we had heavy winds for a couple of weeks.  Because our bins are heavy and permanent, I set them up a bit differently. You can see how I plumbed them in the attached pictures.

The bin on the left is full and running over 100 degrees (it is on the downside of the composting temperature curve). I have loose hay on top for some insulation and then some wire screening and boards to hold a tar paper cover off the manure and allow it to vent air when the fan is on. The right bin is full of hard frozen manure waiting to melt. And the middle bin is about 1/3 full of frozen manure.

We do have a few problems. One of the biggest is that we have been collecting manure that is frozen very hard. Getting this to start composting may not be possible until spring, but it sure would be nice to get it started earlier. So we have had an unusual warm spell for the last 2 days and I have been blasting warm, wet air into the frozen bins. I think this is working as it is beginning to settle. In a couple more days, I may have it running. But I need a better insulating blanket on top. I have used hay and leaves for top insulation and both get wet from condensation and compact - which seals off the air flow. I think something like a quilt made from loose weave plastic burlap or even some sort of netting and filled with crushed Styrofoam packing peanuts might keep in the heat fairly well while allowing air and moisture out. What ever it is, it has to breathe, be impervious to water, and not freeze stiff when wet and cold. I haven’t found the ideal material yet, but I will eventually. If I was really smart, I would also figure out how to run the excess heat from one bin into a frozen bin to get it started. I can imagine how to do this, although it would be a bit of a plumbing nightmare. In any event, this is our operation, and it works quite well. Thanks for getting us started on this.

Comment from Peter: Last winter I had a similar problem in NH with frozen manure being delivered to the compost system and then not thawing out during periods of extreme cold weather (logically). We recommended that our client use heat cables from the greenhouse industry to get the core temperature up to ~70 degrees F to kick start the biology. These are much like block heaters for your car. They are inexpensive and I think will work quite well in your application. As for a cover, I suggest using 2-3 foam board cut to fit with small gaps between individual panels. You can lay on top of these and then bungee cord them into place. These would be inexpensive, easy to handle, and quite effective - at least in concept.

“In the tangled world of toxic and noxious weeds, it is better to kill than be killed”, says Patricia Talcott, instructor of toxicology and veterinary medicine at Washington State University.

“When a horse breeder loses 25 of 28 foals, or a cattle rancher loses 100 cows in a 24-hour period, it’s time to get serious about toxic weeds”, said Talcott, citing two actual incidents of animals encountering toxic plants. ”Plants are not the only killers. Pesticides have a long history of killing animals”.

The complete article was published in the November 21, 2007 issue of the Capital Press. For details, click here.

When it comes to pasture management, there is nothing more challenging than importing toxic and noxious weed seeds to your farm in bales of forage. Weed seeds generally pass through the horse’s gut unchanged and when raw manure is spread out on the pasture, so are the seeds. In fact, weed seeds do accumulate in the soil and can survive for many years until conditions are just right for them to germinate and grow. Soil scientists refer to this accumulation of weed seeds as the “seed bank”; and this is the reason that weeding a garden bed is a never-ending process. 

The only way to effectively eliminate these troublesome weed seeds is through a heat pasteurization process, and the easiest way to accomplish this is by thoroughly composting the manure.

With the O2compost aerated composting system, fresh air (i.e. oxygen) is introduced throughout the mix of materials using an electric blower. The oxygen stimulates the micro-organisms that are already in the mix, and their by-product is heat. In a properly operated compost system, pile temperatures are sufficient to pasteurize the raw material, and the oxygen-rich conditions within the core of the pile eliminate offensive odors. High temperatures also destroy fly larvae and degrade most pesticides and herbicides, improving your horses’ health and yielding a safe, high-quality finished product. For more information on aerated composting, visit: www.o2compost.com.

This phenomenon is not at all unusual. In fact, it is now more the rule rather than the exception. Ours is a complaint driven society and neighbor complaints about odors, dust and flies will bring the local health district and air board right to your doorstep. It simply doesn’t matter that you’ve lived there for 30 years and have been managing the manure the same for that same length of time. Getting angry won’t help - the problem is here to stay unless you take action to solve it.

So, the question is this… “What can we as horse owners do to continue our equestrian way of life and still get along with our neighbors?”

The answer to this dilemma is to properly manage the manure by composting it using the aerated static pile method. Most of the offensive odors result from anaerobic conditions in the manure pile. By maintaining aerobic (oxygen rich) conditions throughout the compost pile, 85% of the offensive odors simply go away - it’s all about the biology. The rest of the odors are absorbed in the 6″ thick cover of finished compost that we place on top of the pile. This layer also serves to control flies by “cooking” the fly larvae in the raw manure.

Getting back on good terms with your neighbors can be a difficult challenge. Here is a strategy that seems to work in most cases:

1. Acknowledge that your horses are creating an odor / fly problem and commit to reducing or eliminating that problem by composting.
2. Install an O2Compost system. For details, refer to “Training” on our website.
3. Provide your neighbors with compost for their garden free of charge and keep them first on your list of people to call when you’ve finished your next batch.

Your greatest defender will be your previously irate neighbor when you get the manure odors and flies under control.

To answer this question, I have designed and built a cover (as shown) and it seems to dramatically help the composting process. The intention is to shed excessive water (i.e. rain or snow) and to retain both heat and moisture derived through the composting process.

I am frankly amazed at how much water collects on the underside of this cover. I knew it would be wet, but as this design is, it is extremely effective at retaining moisture and heat. Given these quantitative results, I now suggest that everyone should cover their Micro-Bins throughout both the active and curing phases of composting throughout the year.

In an effort to continually refine the Micro-Bin approach to small scale on-farm compostnig, we have been conducting our own research to “learn by doing”. The following discussion pertains to the first of three tests that we are currently running.

Test #1 - Retention of Nitrogen with Sweet PDZ

As described on their website (www.sweetpdz.com), “Sweet PDZ is the leading stall freshener on the market and is the odor control and deodorizer of choice for thousands of horse, pet and livestock owners. Sweet PDZ is an all-natural, non-hazardous and non-toxic material (i.e. Zeolite, a naturally occurring volcanic mineral). It captures, neutralizes, and eliminates harmful levels of ammonia and odors. Sweet PDZ is a far superior alternative to lime products for ammonia removal and moisture absorption. Don’t risk compromising your horse’s performance.”

In discussing this product with their Sales Manager, Tom Menner, I asked if the ammonia (i.e. nitrogen) that is captured by their product is retained in the compost, thereby improving the quality of the finished product. Tom’s response was, “That’s a good question, I don’t know. How can we find out?”

To answer this question, we have set up one of my Micro-bins with 2.5 cubic yards of horse manure mixed with sawdust bedding. At the 3-foot horizon (about a foot down from the top), I placed five nylon mesh bags with different mixes of manure, bedding and Sweet PDZ (see illustration and table below). Each sample was prepared in an identical manner with the exception of the type and quantity of Sweet PDZ. The objective is to compost these samples for 60 days and then send representative portions of each sample to the laboratory to evaluate the carbon to nitrogen ratio (C:N). The samples will be pulled around Halloween and the lab test results will be posted here as soon as we receive them.

Plan View (Looking Down)