- Author: Pratap Devkota
I visited an onion field where I saw this interesting emergence pattern with annual bluegrass (Poa annua L.). Onion beds are listed in east-west orientation (as seen in pictures). We can see annual bluegrass emergence only on the south facing slopes and none on bed-tops or north facing slopes. These pictures were taken around noon, the exact time was 12:44 PM. I assume that cultural and irrigation practices are same throughout the field. The only difference I observed was north facing slopes were shaded, but the bed tops and south facing slopes had ample light. With this situation, I am wondering what could be the possible reason for annual bluegrass to emerge on the south facing slopes but not on the bed-tops and north facing...
- Author: Richard Smith
- Author: Steven Fennimore
- Posted by: Gale Perez
Spinach is susceptible to weed pressure because it is produced on high-density 80-inch wide beds with 18 to 42 seedlines. There is no opportunity to cultivate the bed top so all weed control is accomplished by managing weeds in prior rotations, cultural practices, chemical weed control or hand weeding. Clipped spinach is mechanically harvested and must be kept as weed free as possible to reduce hand weeding costs. In the recent UC publication, Sample costs to produce and harvest organic spinach (Tourte et al, 2015 http://coststudies.ucdavis.edu/current/ ) hand weeding costs averaged $440 per acre. However, weeding costs can easily exceed $1,000 per acre in weedy fields, and...
- Author: Sarah Morran
- Posted by: Gale Perez
Annual bluegrass is a common winter growing grass in agricultural and urban environments. It is a well-known weed of turfgrass systems but its ability to grow in a range of environments makes it an increasing problem for other agricultural systems. Annual bluegrass has a short life cycle which may range from annual to perennial, seeds can germinate rapidly and multiple times in a growing season and has a high degree of survival when defoliated or trampled (Galera, Chwedorzewska et al., 2015).
All of these traits make chemical control an attractive and primary mode of management for annual bluegrass. This is true for turfgrass systems where managers use regular applications of PRE and POST herbicides and orchard systems where...
- Author: Chuck Ingels
- Posted by: Gale Perez
The following article is from the UCCE Tree & Vine News newsletter (Jan. 2017).
*Chuck Ingels is a Farm Advisor with the UC Cooperative Extension Capitol Corridor, Sacramento County office.
According to the 2014 USDA-NASS Organic Survey, Washington State was the largest U.S. producer of organic apples, harvesting 429 million pounds (over 90% of U.S. fresh production) from about 14,000 acres, with an estimated farm gate crop value of $210 million. In Oct. 2016, I spoke at an organic orchard floor workshop held in Wenatchee, WA, that covered organic weed and nitrogen management (view a PDF of the...
- Author: Sarah Morran
- Posted by: Gale Perez
Weed management strategies in California are as diverse as the cropping systems grown in it, which cover over 400 commodities and $47 billion in revenue (California agricultural production statistics, 2015). A challenge for growers across the state is to respond to the continuing adaptation, invasion and spread of weeds in their cropping systems. Many factors contribute to the ability of a weed to adapt itself to changing environments, and one focus of research in the weed group at UC Davis includes investigating the contribution that genetic plasticity plays in plant adaptability. Many weed species, particularly grasses, contain multiple genomes (polyploidy). Some plants (and humans) contain a single genome, which means that one...