Livestock feed and manure
Livestock feed and manure is another common way that new weeds can be introduced and spread through fields. It is very important to avoid applying manure that could contain the seeds of herbicide resistant weeds, as this could spark a serious and costly infestation throughout the field in as little as a year.
Tips for preventing weed entry via feed and manure:
1. Avoid purchasing feed or hay, or transporting manure, from areas where there are known infestations of invasive weeds. The product is likely to contain those weed seeds.
2. Inspect purchased feed & hay for Palmer and waterhemp by taking samples and examining them
3. Do not feed contaminated grain or feed supplement
4. If contaminated grain must be used, first grind, roast, or ensile if possible
5. There is some evidence that ensiling crops containing weed seeds can destroy the seeds of some weeds if the temperature and time of ensiling are high enough. There is limited information available, mostly based on Australian weeds, about the success of these practices. The limited information that does exist suggests that ensiling may be more effective on grass weeds than broadleaf weeds. Refer to resources on ensiling to kill weed seeds, and your local extension agents, before relying on this practice.
6. Similarly to ensiling, composting manure and plant matter may destroy weed seeds if the temperature and time are high enough. Composting must be done in a certain manner (creating large, dense, hot piles that are turned regularly) in order for temperatures to stay high enough to kill weed seeds. Refer to resources on composting, and your local extension agents, for tips on this practice before implementing it for weed control.