Outcome of Development and Evaluation of Biologically-Integrated Conservation Tillage Systems for Organic Vegetable Production

Nitrogen availability to the broccoli crop may be a key factor in the yield reduction shown in the
ST treatments. The CT treatment apparently mineralized more N, as indicated by the soil nitrate tests. The
competition of the between-row vegetation for nutrients and water is also a factor. Although the mowing
suppressed the regrowth of the barley fairly well, there was some regrowth of the triticale. In the ST plots,
annual blue grass (Poa annua) combined with other summer annual weeds to form a living vegetative
cover between the rows. Excellent weed control within the broccoli rows was maintained using hand
hoeing, however the clean-cultivated strips were rather narrow (about 6") and competition from betweenrow
vegetation was likely.
The dramatic reduction of flea beetle infestations in the strip-till plots has implications for future
control strategies for organic growers. However the mechanism that is causing the differences in insect
abundance among the tillage treatments is not understood.