- Author: Lynn M. Sosnoskie
A drive around parts of the San Joaquin Valley revealed some fields with Palmer amaranth (Amaranthus palmeri) rising above the crop canopy (See image below).
A male Palmer amaranth in a corn field in Merced County
Palmer amaranth is a tall (growing up to 10 feet in height), dioecious (male and female flowers develop on separate plants), summer annual that grows rapidly and produces significant amounts of seed (upwards of 400,000-1,000,000 per female plant). The species is extremely competitive with many crops, including corn and cotton. In the United States, Palmer...
- Author: Lynn M. Sosnoskie
When we think about weed control in crop production, we often think about 'short-term' result, i.e. weed control after 30 days, weed control after 60 days, weed control at harvest, etc. But weeds and weed control efforts in one crop can significantly influence the density and composition of weeds in following years. The carryover between commodities and seasons is accomplished via the weed seedbank, which serves, in my opinion, as the memory of crop production practices. Weed control successes and failures are reflected by changes that occur in this genetic reservoir. In good years, weeds are successfully controlled and few to no seeds enter the seedbank; in bad years, when weeds escape management strategies, rogue plants...
- Author: Cheryl A. Wilen
One point I always make is that the sooner you control annual weeds, the better. The reduces crop-weed competition, along with a host of other issues caused by weeds (we'll save that for another blog). But the real key to forward-looking weed management is to kill the weed before it produces seeds. Once seeds are produced, they contribute to the seed bank, pretty much ensuring that the weed population will be a continual problem.
But suppose you miss some weeds that are starting to flower but the flowers aren't open yet? I think most growers will just pull or cut the weed and leave it in or near the field.
I want to show you a time-lapse video I took. I cut the flowering stem off of an...
- Author: Lynn M. Sosnoskie
Or rather, think about the weed seedbank, which is the reservoir of viable weed seeds held within the soil profile of an ecosystem. These seeds may be recent additions (e.g. seed that was produced on mother plants within the previous year) or else dormant seeds that have persisted in the soil environment across multiple seasons (e.g. seeds that have not germinated despite exposure to optimal environmental conditions). Whether we realize it or not, our ability to manage weeds in agricultural or horticultural settings can be significantly influenced by the density and diversity of the weeds seedbank. Numerous studies have demonstrated that as weed seed numbers increase, so do the numbers of weeds that survive management...
- Re-posted by: Gale Perez
- Posted by: The Weed's Network
- Author: Steven Fennimore
Introduction
Weed seed are the means by which annual weeds reproduce and disperse. The seed buried in the soil is referred to as the seedbank. Most seed in the soil seedbank were produced in the same field or greenhouse. Some of the seed in the seedbank moved there through the actions of wind, water, animals or the activities of man. Annual weeds usually regenerate from seed stored in the soil seedbank. The seedbank reflects the effectiveness of recent weed management practices in the field or greenhouse and will determine future weed infestations. This article will outline some of the factors that influence weed seedbanks and how to use steam to kill weed seeds.
Weed...