- Author: Bruce Linquist
Rain in May, especially in the amounts we have seen this year are far from ideal for rice growers. It makes establishing seedling, N management and weed control extra challenging. Rain in May is not new. In 1995, 1996, 1998, 2005 average May rainfall in the Sacramento Valley was 2.3 inches and average statewide yields of those years was 73 sacks/ac. Interestingly, in 2011 the Sacramento Valley also received about 2” in May, but yields were 83.5 sacks. Statewide yields over the last 10 years have averaged about 85 sacks/ac.
Here I want to address some nitrogen management concerns. I address three potential scenarios below and some ideas on how to best manage N fertilizer.
Scenario 1. I applied aqua-N before rain to all or part of my field but was not able to get field flooded before the rains.
Aqua-N that was applied before the rain and did not get flooded will be very susceptible to losses. Since the soil became wet (but not flooded), the aqua-N fertilizer will begin to convert to nitrate (NO3) which will be lost to atmosphere (via denitrification) when the field gets flooded. How much is lost? Well it is a bit of a guess but some early research suggests that you lose about 2 lb N/ac per day the field is not flooded. Therefore, if the field received aqua and it was wet for 10 days before flooding, about 20 lb N/ac was lost which will need to be made up later in the season. This is a rough estimate and you should evaluate using a Leaf Color Chart or Green Seeker at panicle initiation (45-50 days after planting). If you see the field yellowing before panicle initiation you should think about adding more N when you see the yellowing.
Scenario 2. I decided not to apply aqua but just go ahead and flood field when the rains started.
In this situation, I believe the best approach is to apply your N around two weeks after planting. The N fertilizer should be applied when water is not flowing within the field. The reason to apply at around two weeks is that before this time, the plant takes up very little nitrogen fertilizer. It really needs it starting around three weeks.
If you plan to keep the field flooded, apply the full amount of N at this stage. As far as N source, urea is a better choice than ammonium sulfate as it will move more easily into the soil. Ammonium will tend to stay at the surface where there is greater chances of losses. Therefore, apply the highest amount of N as urea as possible. You will also need to apply starter fertilizers around this time. Again, assess the crop at panicle initiation to see if more fertilizer N is needed.
Scenario 3. I did not apply aqua or flood my field before the rains
In this situation, you will likely be applying aqua-N into a soil that is wetter than normal. Usually it is applied when the soil is dry and the aqua N is relatively stable for a while (we recommend having field completely flooded within 10 days of application). In a wet soil, the nitrogen will start to convert to nitrate relatively soon (see explanation in scenario 1). Therefore, to minimize N losses, flood the field as soon as possible after applying aqua.
- Author: Luis Espino
Over the winter, I gave a few presentations that touched on armyworms. In the presentations, I usually had pictures of adult armyworms. Several comments I got after the presentations made me realize that armyworm adult moths sometimes are confused with other moths or butterflies that are seen in abundance at certain times of the year. Most likely, one will not see the armyworm moths flying around unless you are driving around the field at night, when they will be attracted to the car lights. They do not fly during the day.
Below are pictures of the true armyworm and western yellowstriped armyworm, the two species we find in rice. I'm not a great photographer, but the pics lets you see that both are somewhat large, thick moths. The true armyworm moth is straw colored, the western yellowstriped armyworm has a greay and browm pattern on the wings. Click on the pictures to see a high resolution image.
The past four years the true armyworm has been the species that has caused problems in rice. Western yellowstriped armyworms have not been very common. This might change this year. I have been finding high number of wester yellowstriped armyworm moths in the traps very early. We will keep monitoring and see what the season brings. For now, enjoy the pictures.
True armyworm
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Western yellowstriped armyworm
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Where: Lundberg Family Farms, 5311 Midway, Richvale, CA
When: Friday, March 22
Agenda
1. 9:45 – Refreshment & Registration
2. 10:00 - Welcome & Organic Rice Production - Jessica Lundberg, LFF
3. 10:15 – Cover Crops in Annual Rotations - Sarah Light, UCCE Agronomy Advisor
4. 10:30 - Fava bean Cover Crop in Ricelands - Dr. Jinguo Hu, ARS Pullman, Genetic Resources
5. 10:45- Selection of Warm & Cool Season Cover Crops - Margaret Smither-Kopperl, PMC
6. 11:00 - Cover Crops in Orchards- Rory Crowley, Nicolaus Nut Company, Inc.
7. 11:15 - Walking to the Field Trial
8. 11:30 - Students Research Spotlight, Fava bean Benefits Potentials – Aaron Alvarez, Amanda Cox, Chloe Dugger, Miriam Pacheco
9. 11:45 – Fava bean Nitrogen Fixation, Dr. Zakeri, CSUChico
10. 12:00- Adjourn and Questions
- Author: Luis Espino
Join UCCE, representatives from Local Groundwater Sustainability Agencies and DWR, for a regional forum to discuss how local agencies are progressing in the implementation of SGMA.
Date: April 5, 2019
Time: 8:00 am - 1:00 pm
Place: Rolling Hills Event Center - Carlino Room, 2655 Everett Freeman Way, Corning, CA 96021
Cost: $10/person, includes lunch
Register online: http://cetehama.ucanr.edu or fill out the resgistration form in the attached program below.
2019 Final Water Meeting Announcement
- Author: Luis Espino
Contact: Jay Thomas: (408) 208-4728 or jay@bcrd.org