- Author: Rachael Freeman Long
- Author: Daniel H Putnam
- Author: Rollie Meyer
When is nitrogen fertilization of alfalfa beneficial? Almost never!
Nitrogen (N) fertilizer is generally not required for alfalfa production since alfalfa can obtain its own N from N-fixing nodules (Figure 1). Alfalfa fixes most (70-90%) of its N needs from the air through Rhizobium bacteria residing in alfalfa root nodules (Figure 1). Since 78% of our air consists of nitrogen gas, this supply of ‘free fertilizer' is inexhaustible. A recent unpublished UC Davis-CSU Fresno study showed 90% of N in alfalfa originated from the atmosphere -- but less when soil N levels were high, for example, in manured fields.
Although there have been some reports of yield and forage quality...
- Author: Vonny M. Barlow
- Author: Eric T. Natwick
Of all of the insecticides evaluated against blue alfalfa aphid (BAA) by Eric Natwick of Imperial County, almost every insecticide applied to alfalfa this spring gave initial knockdown of BAA. Blue alfalfa aphid populations resurged in 7-10 days. Treatments giving 70–75% control (reported by PCA’s) were combinations of a pyrethroid with an organophosphate.
Possible factors for our BAA issue:
- High initial aphid populations
- Smaller than expected populations of predators and parasites; particularly the seven-spotted lady beetle
May be weather related or pesticide...
- Author: Vonny M. Barlow
When: Friday, May 17th, 2013, 12:00 – 2 PM
Contact: Vonny Barlow,Vmbarlow@ucdavis.edu
Where:
- Friday May 17, Riverside County Administration Building Lunch Room, 290 N. Broadway, Blythe CA
What: Informational meeting on Blue Alfalfa Aphid outbreak and future action
Who: PCAs, alfalfa producers, crop protection industry
Why: Severe outbreaks of Blue Alfalfa Aphid have been reported in the San Joaquin Valley as well as other locations in CA. Large populations have been difficult to manage in...
- Author: Daniel H Putnam
New video and recent protests highlight controversy.
For those of you interested in the on-going public discussion about Genetically Engineered (GE) or Genetically Modified (GMO) foods, check out a new video produced for public television ‘The Next Meal: Genetically Engineered Foods’, airing tonight in San Francisco, and in May at other PBS stations. You can download it here:
http://science.kqed.org/quest/video/next-meal-engineering-food/
This video contains a full (and balanced) discussion of the science of genetic engineering itself, the...
- Author: Carol A Frate
Many of us think about too much water killing alfalfa during the hot days of summer. And this does happen, especially at the tail end of fields where water may collect and stand for hours after the irrigation has ended. When temperatures are over 100 oF and the soil is saturated for extended periods, roots can essentially suffocate due to lack of oxygen. Plants die very quickly and roots begin to disintegrate. Because the root zone is usually saturated from the soil surface for a depth of several inches or even feet, the entire root rots. This situation is referred to as “scald” and is a physiological process rather than a pathology process.
There is another situation where saturated soil leads...
