> Your work sounds very interesting. I few questions as I am involved with
> large scale organic vegetable production in the Colombia River Basin were we
> are using manure (some chicken but mainly beef), composts and cover crops to
> build soils.
> * Your comment on drought resistance is typical of our observations
> over a number of farms in WA, OR and CA. How long have the plots you are
> working with been managed under an organic system before you applied your
> treatments?
This is only the second (and probably the last) year that the plots on one of
the experimental stations will be in use for _my_ research. The land was
fallow for three to five years prior to planting rye/vetch in October, 1996.
It is hoped that the project will continue for several years, and the main
experimental station worker for the organic unit (and the station manager, and
asst. manager) know the importance of maintaining these plots for years to
come.
> * Can you put any numbers against the organic vs conventional
> treatments for the amount of root mass.
We will be taking root dry masses for the plots this year, but with severe root
knot infestations, I'm not sure how reliable they will be.
> * Do you have any yield data between the treatments.
Yes. In both years (first and second years that treatments were in place)
tomato yields were significantly higher in plots amended with composted cotton
gin trash (CGT), and hog waste solids (HW) at my first experimental station
site. Harvests at the second site will be in another week to ten days (wet
spring, late transplanting).
> * Over the years we have consistently seen a higher brix level in
> organically grown tomatoes compared to conventional grown. Have you looked
> at brix levels
Haven't looked at brix levels. I've got a full plate now. I'm looking at
different types of bacteria (total culturable, fluorescent pseudomonads, and
enteric), fungal populations (total fungi, Fusarium spp., Trichoderma and
Gliocladium spp., and Phytophthora and Pythium spp.), thermophilic
microorganisms (mainly Actinomycetes, Penicillium spp., Aspergillus spp.),
Free-living nematodes (trophic groups to genera) and plant parasitic nematodes
(to species), as well as yields, soil respiration, and physical and chemical
properties of the soil.
> * What levels of root knot are you dealing with. I have the task of
> reducing low to moderate levels of root knot in two circles which have just
> entered transition to organic. I am looking at ways to reduce levels before
> the land becomes organic. For financial and management reasons we do not
> want to remove the alfalfa already in these fields as they go though the
> transition period. We could grow Sudan or marigolds in the last few months
> of the transition period but I would also like to work on the reduction of
> nematodes over the next 2 years and not just rely on the effectiveness of a
> single green manure crop. Any thoughts on how we might increase
> bacterivorous nematode levels over the interim.
Incredibly high RKN populations. Last year at harvest in some plots (there was
contagious dispersion, too variable for statistical significance) we had more
than 5000 RKN J2 larvae per 500 cc of soil.
As for increasing numbers of bacterivorous nemas, by increasing the bacteria,
the populations of worms will increase. We have higher populations of
bacterivorous nematodes in soils containing CGT and HW. There are a multitude
of factors to be considered when thinking about increasing numbers of nematodes
in the soil. One needs to consider the ecology of the system. All
bacterivorous nematodes require bacteria (Obviously), but some genera (like
Rhabditis, Mesorhabditis, and the Rhabditidae in general) require _large_
numbers of bacteria, and a nutrient-rich environment on which the bacteria feed
in order to maintain high populations. Inevitably, the Rhabditids are a
transitional population of nemas. I don't really have time right now (and
neither do you, probably) to get too in-depth.
> * I am just beginning a research program on compost recipes so any
> thoughts on ingredients to boost bacterivorous nematodes would be very much
> appreciated.
It's hard to say. By far the most important factor will be proximity of
organic amendments to farms, as the large amounts of materials needed (I
require 14.7 tons/acre HW, and 37 tons/acre CGT for 100 lbs/acre N) will need
to be transported to the sites.
>
> best of luck with you work
> Cheers
> Alec McErlich
> Cascadian Farm, Inc
> Sedro-Woolley, WA 98284
> http://www.cfarm.com
-- End of excerpt from alec@smallplanetfoods.com
-- Russ Bulluck Graduate Student Plant Pathology NCSU Box 7616 Raleigh, NC 27695 ------------------------------------------------------------- The soil population is so complex that it manifestly cannot be dealt with as a whole with any detail by any one person, and at the same time it plays so important a part in the soil economy that it must be studied. --Sir E. John Russell The Micro-organism of the Soil, 1923 -------------------------------------------------------------
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