Australian Herbicide Resistance Initiative (AHRI)

iHSD Mill Efficacy on the Seeds of Australian Cropping System Weeds

Our latest paper, published in the journal Weed Technology by Walsh, Broster & Powles is entitled “iHSD mill efficacy on the seeds of Australian cropping system weeds”.

The term “harvest weed seed control” is used to describe several techniques (narrow windrows burnt, chaff carts, grain harvest chaff & straw baling, chaff-lines, chaff decks, HSD) that can be used at grain harvest in Australian grain cropping.  These techniques target destruction of weed seed harvested during the grain harvest.  The majority of the weed seed processed by the grain harvester usually exits in the chaff fraction.

The HSD, originally developed as a unit towed behind the grain harvester (Walsh, Harrington, Powles, Crop Science, 2012), has now been incorporated into the rear of the grain harvester where it destroys the weed seed containing chaff fraction (termed the iHSD).

This work quantified the efficacy of the iHSD to destroy the seed of a range of crop weeds. The iHSD is an impact mill and when operating at the recommended 3000 rpm this work demonstrated very high (>95%) kill of seed of a wide range of weed species. This efficacy was maintained regardless of the crop type (wheat, barley, canola, lupin) and chaff moisture content. This research was essential in establishing the high efficacy of the iHSD across a range of weed species and crop types.

Gratitude is extended to the GRDC for funding this research and to many undergraduate agricultural science students who did the tedious counting of weed seeds necessary for this research.

This work was led by AHRI research leader Michael Walsh who during the course of this work was appointed to the important position of Director of Weed Research at the University of Sydney.

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