Question
Hi Frank and Vicky --

I'm not certain if this is the proper forum for this question, but I thought it might be a good place to start.  

I live in Minnesota and am a breeder of Peruvian Cavies (long haired guinea pigs).  My herd is comprised of approximately 85 animals kept in various sized cages depending upon their current status.  You can well imagine the volume of soiled bedding generated by all these critters!  

The cage pans are first lined with paper, topped with a thin layer of wood stove pellets (these do a superb job of absorbing urine) and finally a thick layer of wood shavings.  When I clean, I scoop the soiled bedding out into a large leaf/garden bag for later use and roll up the newspaper and dispose of it.  

Thus, the bedding is a mixture of manure, urine and some hair.  This is utilized as a mulch for my vegetable gardens and perennial beds during the summer; over the winter, I simply dump the used bedding on the vegetable beds along with wood ashes from the fireplace.  In the spring, there is approximately a six to eight inch layer of used bedding spread over the beds.  I then sprinkle some Milorganite on it and rototill the beds before spring planting.  

After having done this for past four years, I'm surprised that the bedding appears to decompose very quickly.  The soil has also improved remarkably and does an admirable job of retaining moisture during our hot (and increasingly dry) summers.  All the vegetables perform very well with the standouts being root crops - incredible carrots!

So, finally to my questions --

1)  Are you aware of any studies done on the fertilizer value of cavy manure?  Is it high in nitrogen - similar to rabbit manure?  

2)  Could there be a detrimental effect from long term use of the bedding on the soil?  Excessive salts in the urine?  Depletion of soil nitrogen to break down the wood cellulose?  

Would you have any other suggestions for making better use of this product?  

In addition to my own vegetable beds I also have a plot in a community garden in Minneapolis - the folks there look askance when all this bedding accumulates before being tilled under in the spring.  It's their belief that I'm doing more harm than good - so, I'm just looking for some input from a third-party!

I hope that this hasn't become too long and involved!  Being an avid organic gardener, I'm always looking for ways to better use what nature supplies!!  

Thank you in advance for help and guidance!  I look forward to receiving your reply!

Andy  

Answer
Thank you for a great question!

Cavy manure is very high in nitrogen, it is a cold manure and can be added right to the garden. I would also use your mixture as a mulch around your plants during the growing season to keep your soil consistently moist and the soil temperature even, and rototill it in at the end of the growing season before adding the winter layer. This would allow it to break down twice during the process of decomposing, increasing the benefits to the soil, and allowing time for the natural worms in the soil to multiply.

The only concern I can think of would the kind of wood used to make the stove pellets, and chips, since wood resins and binders (lignin) occurring naturally in the sawdust hold wood pellets together. Cedar and pine have resins which might, over time, affect the respiratory systems of you and your pets: http://www.trifl.org/cedar.shtml

You also have the ideal components for composting or vermicomposting. Gardens benefit even more from worms and worm castings than manures or compost providing increased moisture retention,  better aerated soil, and increased soil fertility. Check out this website for vermicompost information: http://revolution.3-cities.com/~fuzyfarm/Worm.htm You could add the entire waste mixture as a compost, or vermicompost, layer and utilize the newspaper as well.

Tests performed by the U.S. Department of Agriculture show that soil worked by worms is ten times richer in plant nutrients than soil that was not worked by worms:
   Worm Soil Nutrients % Increase:
       Nitrate of Nitrogen         500%
       Available Phosphorous       700%
       Exchangeable Potassium     1200%
       Exchangeable Calcium        150%
       Organic Carbon              200%

Your concerns about salts in the urine, any hot spots where urine may be concentrated and may effect the soil or plants, and any loss of nitrogen in the breaking down process of the wood cellulose would be alleviated by a composting process.

You can also check our website, Avant-Gardening: Creative Organic Gardening, for more information about soil building and composting: http://www.avant-gardening.com/composting.html and
http://www.avant-gardening.com/ogardening.htm

You might consider using alfalfa hay, which is also high in nitrogen, instead of the wood chips and pellets. This could be then be shredded and composted, or vermicomposted, and used in the same way as your current mixture.

We have found that using a mixture of shredded alfalfa hay and a cold manure (sheep, rabbit, cavy) as a mulch increased the humus content of the soil to the point that we had handfulls of native worms in our soil.