Non-chemical weed management in linseed

Several field experiments were conducted on certified organic farms in Canterbury over two growing seasons to test different methods for weed management in linseed. Methods included tine weeding at different growth stages, thermal weeding and sheep grazing. The results showed no significant benefit from tine weeding under low weed pressure. If tine weeding is required with high weed pressure, then higher sowing rate of linseed should help to overcome population loss caused by the operation. One experiment compared flame weeding and steam weeding at different stages of linseed growth. Linseed was extremely sensitive to heat at post-emergence and moderately sensitive at pre-emergence stage. Sheep grazing at two intensities, lax and hard grazing, was tested and resulted in reductions in populations and biomass of both weeds and linseed. Weeds were able to take advantage of the opened canopy and grew faster. None of the grazing treatments improved yield and a second grazing at either intensities caused yield reductions in excess of 17%. Grazing increased the number of branches on linseed stems and may have a place in prevention of lodging.