> Thus, optimised compost making, with minimised energy and labour inputs are > essential. Therefore sieving is just an extra handling process, which I > don't want to get into. I have had this experience in an urban garden and > simply cannot afford to go that route now that I am working a larger area.
This is a common misconception. Sieving, sifting, screening, call it what you will, is not a difficult process necessarily, even on a relatively small scale and with small equipment. The payback for the second handling is the ability to use chunky materials in the composting process that ensure good aeration and provide fungal food. The tool I created for the small scale urban gardener is the Cantopper and you can do about a cubic yard per hour with it, give or take. http://www.mastercomposter.com/teuton/index.html Small but useful trommel type sifters can be seen at the following sites: http://fdt.net/~windle/screen/ http://www.vermico.com/harvester.html http://www.vermitechnology.com/worm_feed_bins.html Small commercial shaker type screens can be seen here: http://www.brockwoodfarm.com http://www.royerind.com/html/model42.html A DIY shaker screen very useful for small farm scale work is Leon's Big Sifter, http://www.mastercomposter.com/leon/leonsift.html Not portable, though. Another lively option for screening is to rent in a larger commercial composting screen. Sizes range from the Orbit Screen www.orbitscreens.com all the way up to big industrial trommels. An Orbit Screen might be useful for a group of small farmers and landscapers to share. Why bother screening? In my opinion, the reasons are threefold: Use of chunky material makes aerobic composting more likely; Screening materials before composting and vermicomposting prevents lumps of undigested materials; Screening the end product allows it to be spread evenly in small amounts. For example, a tool we are considering for the orchard is http://www.wikco.com/800.html a big spreader. Sifted compost will go through a spreader like this, especially if mixed with alfalfa meal or rock dust. Manure spreaders or golf course topdressers will deliver much more compost, but a way to get smaller amounts out there between topdressing amounts and the amounts of microbes that go out in compost tea, seems to require sifting for reasonable spreading, I am thinking. Also, remember that using large chunks at the beginning of the composting process will still result in fewer such chunks at the end, when the microherd will have digested and weakened the largest stuff. Another treatment of brush which may be useful to some folks is hugelkulture, building growing mounds on brush bases that fully break down over about a four year period. Human creativity has many possible answers! Frank Teuton
