On Fri, 24 Mar 1995, Dick Richardson wrote:
> Ann, you pose the question:
> I'd be interested in learning what
> >it is that is more beneficial about composting in-situ - in the soil -
> > as against ahead of time. Evidence from the literature?
> The direction I'm speaking about in management of manure may be different
> in the "north country" where you're working. I'm referring to the role of
> dung beetles, earthworms, and such. The dung beetles can bury 6000 lbs
> fresh manure per acre per day, from the estimates of Walt Davis, a
> colleague in southern Oklahoma, when he begins managing his livestock to
> avoid poisoning the invertebrates in the soil -- grazing plans that break
> lifecycles of parasites without pesticides -- and the dung beetle
> populations build up as the soil temperature reaches 50 degrees F or
> thereabouts. There are no piles of manure after two days! The result is
> that the soil health and vegetation really jump, and toxicity is not found.
> We also tested raw sewage and the dung beetles went for it with great
> vigor, but the treated sewage (biosolids) was not palatable. This is no
> surprise, since the treatments required for "health reasons" are partly for
> reduction of smell and attraction of flies. For treatment of sewage, most
> of the proteins have been converted to ammonia, and the same loss holds for
> readily available carbon. Further, composting causes a net loss of organic
> matter that soil organisms can use, but the organisms have to be present in
> the soil in suitable numbers and have conditions favorable for matching
> their growth and utilization with the amounts of uncomposted materials
> applied. This requires good management, matching the supply with the
> demand, so to speak.
> If we look at the sewage as microbial and invertebrate food, and we are
> trying to increase these populations in the soil, then there surely will be
> some balances needed to avoid over-doing the application, which you pointed
> out. If we dump even good stuff on at the wrong time or in the wrong
> amounts, then we certainly can expect problems. The direct metering out by
> livestock as they are grazing helps stay "within the window". Bringing
> urban equivalents to the rural sites doesn't have such a built-in meter.
> In Austin we have had land applications of biosolids for several years, and
> other locations, such as near St. Paul, MN have injected biosolids before
> de-watering. It's been fine for corn and great for the land in general.
> However, it seems to me that the key is blending the return process of such
> resources into the needs of the soil organisms.
> In another recent post, Karen Grobe commented
> "... All farmland should not receive compost. Some farmland is used to
> produce cattle, and it would not be appropriate to use compost ... on
> grazing land."
> I would disagree to the point that sometimes compost (or biosolids) may be
> needed to "jump start" to get grazing land into a good state of health.
> The importance for the soil health may be less in terms of the production
> of "food" products than in the fact that it is watershed. If land managers
> are able to increase infiltration rates and water holding capacity
> sufficiently, we see springs return to perennial flows, and watertables
> high enough to maintain perennial vegetation (grasses and others) in
> healthy states even during drouth conditions. However, if properly
> managed, grazing land (pasture or rangeland) seems capable of improving and
> remaining healthy through the recycling of organic matter from the
> livestock alone. Certain minerals in certain soils, however, may be
> another matter.
> R. H. (Dick) Richardson Office: 512-471-4128
> Zoology Dept. Home: 512-476-5131
> Univ. of Texas FAX: 512-471-9651
> Austin, TX 78712