Chaff carts

A chaff cart is a large bin that follows the combine during harvest, collecting the weed-containing chaff that is ejected from the combine. By collecting chaff that would otherwise be blown back onto the field, the cart removes potential weed seeds from the field and allows them to be disposed of. The Australian Herbicide Resistance Initiative tested chaff carts on several commercial harvesters and found that they collected between 75-85% of annual ryegrass seeds that entered the combine during harvest (Walsh and Powles 2007).

Chaff cart pulled behind a combine in Australia. Photo: Michael Walsh, Australian Herbicide Resistance Initiative

Chaff cart pulled behind a combine in Australia. Photo: Michael Walsh, Australian Herbicide Resistance Initiative

The collected chaff is then emptied into a pile either on the field to be burned, or off of the field.  Burning the pile on the field minimizes the risk of spreading weed seeds to other areas. Burning in a large pile can create temperatures high enough to kill the weed seed. The feasibility of the burning method in the mid-Atlantic partly depends on state and local burning regulations. Alternatively, the chaff pile may be composted to destroy the seeds; proper composting methods create internal temperatures hot enough and for long enough time periods to destroy most weed seeds.

Chaff carts provide a relatively simple method of HWSC that doesn’t require highly specialized equipment, making adoption relatively simple compared to other HWSC methods. However, the primary challenge of chaff carts is that their size and weight add on to already large harvest equipment. This may add a level of difficulty on small fields and more potential for soil compaction.

Chaff carts are currently used by some Australian small grain producers, and are being tested by the University of Arkansas in soybeans, in collaboration with the Australian Herbicide Resistance Initiative. They are not currently being tested in the mid-Atlantic.