Targeting Weed Seeds In-Crop: A New Weed Control Paradigm for Global Agriculture

Abstract

The widespread evolution of multiple herbicide resistance in the most serious annual weeds infesting Australian cropping fields has forced the development of alternative, non-chemical weed control strategies, especially new techniques at grain harvest. Harvest weed seed control (HWSC) systems target weed seed during commercial grain harvest operations and act to minimize fresh seed inputs to the seedbank. These systems exploit two key biological weaknesses of targeted annual weed species: seed retention at maturity and a short-lived seedbank. HWSC systems, including chaff carts, narrow windrow burning, bale direct, and the Harrington Seed Destructor, target the weed seed bearing chaff material during commercial grain harvest. The destruction of these weed seeds at or after grain harvest facilitates weed seedbank decline, and when combined with conventional herbicide use, can drive weed populations to very low levels. Very low weed populations are key to sustainability of weed control practices. Here we introduce HWSC as a new paradigm for global agriculture and discuss how these techniques have aided Australian grain cropping and their potential utility in global agriculture.

Nonconventional Weed Management Strategies for Modern Agriculture

“…Many seeds are retained in the soil seed bank, which creates problems after emergence in standing crops. Weed populations can be decreased by removing their seeds at maturity (Walsh et al 2013). This strategy eliminates potential seeds from the system that can be deposited in soil or may germinate in coming seasons.…”

“…Harvest weed seed control has been developed in Australia and has shown promising results. This strategy can be implemented with the Harrington seed destructor (HSD), chaff carts, narrow windrow burning, and bale direct (Walsh et al 2013). Each technology is based on the principle of weed-seed collection during grain crop harvest and seed destruction to avoid the replenishment of the seed bank.…”

“…Walsh et al (2013) comprehensively reviewed the weed man-agement potential of harvest weed seed control. Their key recommendations have been highlighted in this review and the missing links have been elaborated.…”

Weed seed shatter in spring wheat in Alberta

“…One non-herbicidal weed control strategy that has helped Australian producers manage their herbicide-resistant weed populations is harvest weed seed control (HWSC) (Walsh et al 2013). …”

Palmer Amaranth (Amaranthus palmeri) Management in GlyTol®LibertyLink®Cotton

“…Preventing weed seed inputs to the soil seedbank is an effective means of reducing the impact of weeds on subsequent crops while prolonging the efficacy of herbicide-based weed management programs (Walsh et al 2013). Intensive tillage, stubble burning, crop desiccation, and windrowing using a chute mounted to the rear of the harvester to concentrate the straw and chaff residues into a narrow strip, weed seed collection at harvest using DOI: 10.1614/WS-D-15-00210.1chaff carts or baling systems, cover crops, and herbicide programs are some of the methods used for preventing the influx of weed seeds into the soil seedbank (Chauhan and Abugho 2013;Devenish and Leaver 2000;Fogelfors 1982;Storrie 2014;Walsh and Powles 2004).…”