While organic vegetable production is well established in
the US and
elsewhere, organic grain crop production has proven more difficult to
manage. Perennial weed species [e.g.,
Johnson grass [Sorghum
halepense (L.) Pers.], wild garlic
[Allium ursinum L.], fungal diseases [Fusarium spp.], and insect outbreaks [true armyworms, Pseudaletia unipuncta]} may be
manageable by organic methods in small areas of high value vegetable crops, but
may prove much more complex to manage organically in large areas of modest
margin grain crops. Our objective was to
compare the yields of corn [Zea mays
(L.)], soybean [Glycine max (L.)
Merrill], and wheat [Triticum aestivum
L.] in three organic cropping systems.
For this presentation, we will focus on grain crop yields in transition
from a conventionally managed alfalfa [Medicago
sativa L.] system. Each tested
organic cropping system was managed as a two-year rotation with decreasing
grain crop intensity as follows: 1) corn
followed by 19 months of orchard grass [Dactylis glomerata L.]/red
clover [Trifolium
pratense L.] mix (one grain crop
each two years), 2) corn, winter rye [Secale cereale L.] cover
crop, soybean, and hairy vetch [Vicia villosa L.] cover crop (two grain crops each two
years), and 3) corn, winter wheat, and double crop soybean (three grain crops
each two years). Further, we started
each rotation in both its first year and its second year (in order to evaluate
year effects), and included two locations [a Maury silt loam (fine, mixed,
semiactive, mesic Typic Paleudalfs) near Lexington, KY and a Crider silt loam
(fine-silty, mixed, active, mesic Typic Paleudalfs) near Princeton, KY]. Yields will be reported from all three
organic grain cropping systems for 2005 (Lexington
only) and 2006 (both locations).