Average annual precipitation in California is 200 million acre-feet, out of which 42% of water is used for agriculture while 11% is used in the urban areas (municipal and industrial users) and the remaining 47% by the environment (native vegetation, ground water, and oceans) (Doug Parker, personal communication). According to the National Drought Mitigation Center's Drought Monitor, 95% of California is currently in a severe to exceptional drought condition. Drought has impacted California agriculture in different ways in different regions. Depending on crop needs, geographic location, and availability of ground water, production of each crop is affected in one way or the other. Compared to the Central Valley which is affected most by the drought, agriculture on the Central Coast and Southern California is less affected according to a study conducted by the Center for Watershed Sciences at University of California Davis.
Some strawberry and vegetable growers in San Luis Obispo and Santa Barbara Counties were contacted recently to assess the current impact of drought. Their feedback helped to put together the following summary of the current status and recommendations to address drought conditions.
Strawberry growers continue to use available groundwater although with concern for future availability. Current impact of the drought on strawberries:
- Strawberries require 21-24 acre inches of water and rainfall accounts for 3-6 acre inches during normal rainfall years. Rainfall leaches salts away from the root zone while meeting irrigation needs. Compared to three years ago, it is estimated that there is up to a 10% increase in some salts, especially calcium and magnesium due to the current drought conditions. This could lead to 5-10% reduction in fruit yields, but severe salt injury could cause higher losses. Additionally, plants would be vulnerable to pests and diseases which could lead to further yield reduction.
- Strawberries are very sensitive to salinity and frequent irrigation is practiced to prevent the accumulation of salts in the root zone. Growers are aware of diminishing groundwater resources and are carefully monitoring water and salinity levels. Extra irrigation to push out salts from the root zone results in nutrient leaching.
- These practices are expected to continue as long as groundwater is available, but acreage could diminish if groundwater becomes unavailable.
Strategies to address drought conditions in strawberry production:
- Continue to monitor groundwater levels and provide irrigation to meet water needs as well as to leach out salts.
- Monitor health of plants and regularly scout for pests and diseases which might require more timely treatment actions than usual because plants are already under stress.
- Check nutrient levels in the soil and plant and compensate as needed if irrigation is causing nutrient loss.
- Modify leaching fractions based on salt levels and plant maturity to flush salts away from the root zone.
- Reconsider acreage planted based on groundwater availability to minimize losses.
Vegetable growers are experiencing the impact of drought conditions on their production and are currently relying on available groundwater.
- Water needs for vegetables vary from about 7 to 36 acre inches based on the crop and location. Rainfall during a normal season contributes up to 24 acre inches depending on the crop and season.
- Drought conditions resulted in increased salinity, which has caused 10-20% reduction in yields of some crops and a significant increase in pest and disease pressure. Some growers are managing without any yield losses.
- Some growers have already reduced their acreage by 10% or more while others continue to maintain the current acreage.
- Reducing or completely avoiding pre-irrigation is currently practiced by some growers to cope with water shortage. This practice has also increased salinity in the soil and increased weed populations.
- Some growers have reduced fertilizers or are choosing ones with less salt content.
- In order to monitor salinity and nutrient levels, additional expenses are incurred for water, soil, and plant analysis. Increased weed, pest, and disease problems have also increased management costs.
- Some growers are prepared to reduce acreage up to 25% if drought conditions continue.
Strategies to address drought conditions in vegetable production:
- Continue regular monitoring of groundwater levels, salinity conditions, nutrient status, and provide irrigation and fertilizers as appropriate.
- Regularly monitor for pests and diseases and make timely management decisions.
- Reduce or avoid sprinkler irrigation and use drip irrigation as much as possible.
- Continue to reduce or avoid pre-irrigation to conserve water.
- Modify leaching fractions based on the current salt and crop conditions and administer irrigation as needed.
- Modify acreage to suit future water availability.
My current research is evaluating the potential of entomopathogenic fungi in improving water and nutrient absorption by plants, which could play a role in conserving water resources.
Acknowledgements: Thanks to the strawberry and vegetable growers in San Luis Obispo and Santa Barbara Counties who responded to the survey on drought impact and provided their valuable feedback.
UC and other resources:
California agriculture faces greatest water loss ever – College of Agricultural and Environmental Science, UC Davis
Center for Watershed Sciences - UC Davis
Water use in California – Public Policy Institute of California
California harvest much smaller than normal across crops – The Sacramento Bee
In virtual mega-drought, California avoids defeat – Los Angeles Times
Ken Tate has agreed to expand his presentation at the upcoming California Ranch Stewardship Workshop on October 21 from 1- 4 pm at the Farm Advisors' office! His presentation is entitled Research Update: Grazing and
Environmental Topics. This is a very timely subject as Ken will be highlighting new research that has focused on water quality, sensitive species conservation and riparian health – important to both Mendocino and Lake County ranchers as they deal with on-going regulations. Ken will provide the science that landowners need to be informed when dealing with regulatory agencies. You don't want to miss it!
Remember. Preregistration ($15) is required either by credit card, check or cash at our web site at: http://ucanr.edu/survey/survey.cfm?surveynumber=13795 to ensure we have sufficient handouts and refreshments (We've had numerous requests for Schat's cookies.). If you'd like to pay by check or cash contact our office and talk to either JT or Tanis. (707) 463-4495.
Hope to see you there!
November 7, 2014
• What the U.S. Drought Monitor means to you
• How CA Ranchers are coping with the drought
• New feeding strategies for livestock in drought
• NOAA's forecast for the coming season
The map tells the tale of California's relentless drought, its location and severity. This workshop will tell you the story of the Drought Monitor, in particular how the map may help you qualify for drought relief assistance – and how local California experience and information can be used to inform the drought mapping process. Results will also be shared from current studies of how ranchers are impacted by and managing for drought on their ranches, as well as on the newest livestock drought feeding strategies. The California state climatologist will present the forecast for the coming season. The workshop will be on the UC Davis campus and webcast to the majority of participants at local satellite locations across California. The workshop recordings will be posted on-line.
Questions and comments from local satellite webcast locations will be included throughout the workshop.
|9:15 AM||Registration Opens and Morning Refreshments Served|
|9:50 AM||Welcome, Ken Tate, UC Davis and UC Cooperative Extension|
|10:00 AM||U.S. Drought Monitor: Setting the Context and Introduction of Speakers, Mark Svoboda, National Drought Mitigation Center|
|• A Behind the Scenes Look at the Drought Monitor: History, Tools, and Methods, Eric Luebehusen, USDA|
|• How to get information into the US Drought Monitor Process, Brian Fuchs, National Drought Mitigation Center|
|• The California Drought of 2011-14: Brief History and Current Impacts, Brad Rippey, USDA|
|11:00 AM||Questions and Discussion about the Drought Monitor and California, Chad McNutt, NOAA
Discuss the Drought Monitor and how California's ranching and range community can inform the process.
|12:00 PM||Lunch Provided by the UCD Rustici Rangeland Endowments|
|1:00 PM||California Ranchers' Experiences with Drought, Leslie Roche, UC Davis
Insights to on-ranch drought impacts, outlooks, and management based on surveys and interviews of over 500 ranchers living through this drought.
|1:30 PM||New Livestock Drought Feeding Strategies, Glenn Nader, UC Cooperative Extension
Tips for improving the nutritional quality of low quality feed products, and supplementing livestock diets on rangelands.
|2:00 PM||Seasonal Climate Forecast and Opportunity for Q&A's for the Coming Season, Michael Anderson, California State Climatologist, California Department of Water Resources|
|2:30 PM||Closing Remarks, Tim Koopmann, President, California Cattlemen's Association|
Contact for Information and Registration – Tracy Schohr at email@example.com or (916)716-2643(916)716-2643
Workshop and Webcast Locations – UC Davis campus and webcast to Auburn, Ventura, San Luis Obispo, Bakersfield, Tulare, Merced, Ukiah, Redding, Susanville, Yreka – more locations and details coming soon.
U.S. Drought Monitor – http://droughtmonitor.unl.edu/
U.S. Drought Monitor California– http://droughtmonitor.unl.edu/CA
UC Rangeland Watershed Laboratory Drought Page – http://rangelandwatersheds.ucdavis.edu/main/drought.html
Bagrada bug (Bagrada hilaris) is an invasive pest that was first reported in California in 2008 in Los Angeles County. It is currently reported from the following counties in California on various host plants.
Biology, damage, and management of Bagrada bug
Voraz plaga ataca huertos y jardines
National Hispanic Heritage Month (September 15 – October 15) celebrates the contributions, culture, and history of Hispanic and Latino Americans originating from Spain, Mexico, Puerto Rico, Central America, and South America. These Americans make up the largest minority group in the United States and represent a very important part of the UC Statewide IPM Program's audience.
In recognition of National Hispanic Heritage Month, we'd like to highlight several important resources available from UC IPM to help Spanish-speaking audiences manage pests and apply pesticides safely.
For our Spanish-speaking urban audiences, several short videos on common pests such as ants, spiders, snails, bed bugs, and mosquitoes are available as well as Quick Tips (Notas Breves) offering advice on many pest problems and information on using pesticides safely. There are also 16 touch-screen computer kiosks located in various locations around the state where users can find pest and pesticide information in English or Spanish.
For maintenance gardeners preparing to take the California Department of Pesticide Regulation's Pesticide Applicators exam in the category Q, UC IPM offers a study guide and free online training course in Spanish.
National Hispanic Heritage Month actually originated in 1968 as “Hispanic Heritage Week.” In 1988, it was expanded to an entire month-long event in order to include many important historical events such as the anniversary of independence of Mexico, Chile, and several Central American countries (Belize, Costa Rica, El Salvador, Guatemala, Honduras, and Nicaragua). It ends after Columbus Day.
For more on other pest management and pesticide safety information available, please see the UC IPM Web site.