Posts Tagged: climate change
One of the forces driving agricultural experiments in California's fertile San Joaquin Valley is climate change, reported Mark Schapiro on Grist.org. Although some sources still don't feel completely comfortable with the concept.
"Whether it's carbon built up in the atmosphere or just friggin' bad luck, the conditions are straining us," said John Duarte, president of Duarte Nursery.
The state's fruit and nut orchards are taking the most heat as conditions change. A fruit or nut tree planted today may be ill-suited to climatic conditions by the time it begins bearing fruit in 5 or 10 years. Between 1950 and 2009, “chill” hours trees needed annually to reboot trees' metabolic system for the spring bloom had already declined by as much as 30 percent, according to a California Department of Food and Agriculture study.
“If trees haven't had that low-chill period when they wake up in the spring, it's like being up all night and then trying to go to work.” said Mae Culumber, a nut crop advisor with UC Cooperative Extension in Fresno County.
Researchers have already observed that cherry, apricot, pear, apple, pecan and almond trees are often less productive than they used to be.
The article said farmers may turn to pistachio trees to weather a warmer and dryer California. Pistachio trees require one-third to one-half as much water as almond trees. During droughts, pistachio tree metabolism slows and when water returns, they start producing nuts again. And they can produce nuts for 80 years or longer, almost four times the life span of an average almond tree.
For field crops, scientists are looking at improving the soil and transforming growing systems to help farmers adapt to the warming climate.
“When I drive to the Central Valley, I get goosebumps; I feel the urgency,” UC Davis agronomist Amélie Gaudin said. “I see an agriculture that is basically hydroponics. It's like a person being fed/kept alive by an IV.”
“What happens when you no longer have the sugar-water?” she adds.
Gaudin is focusing on using agroecological principles to develop efficient and resilient cropping systems. Planting cover crops and reducing tillage show promise for mitigating the impact of climate change in the valley.
KQED reporter Mark Schapiro discovered a "center of insurrection" at the UC West Side Research and Extension Center in Five Points, where UC Cooperative Extension cropping systems specialist Jeff Mitchell has been building soil on a research plot for 20 years.
Schapiro's story was part of a series titled "Reckoning in the Central Valley," a collaboration between Bay Nature magazine and KQED Science examining how climate change is exposing the vulnerabilities of California agriculture.
In the Central Valley, climate change is disrupting the predictability that is key to maintaining a profitable industrial agriculture system. Mitchell believes that employing practices that build soil - such as reducing or eliminating tillage and planting cover crops - will help farmers ride the wave of climate change.
It's that cover-cropped field “that is the real disruptor here," Mitchell said.
The soil in test plots where cover crops were grown are loaded with far more organic matter than soil in fields where cover crops were not grown. The organic matter improves water absorption, making the land more resilient to drier conditions. Fields with cover crops also sequester carbon and produce crops that may be more nutritious.
“What you see in Five Points,” said Daphne Miller, a physician who studies the links between the health of the foods we eat and the soil in which they're grown, “is that the plots with the greatest diversity of cover crops had the most diverse microbiome in the soil.”
In 2018 the Ojai Valley Land Conservancy (OVLC) accepted a grant from the Resources Legacy Fund on behalf of Watershed Coalition of Ventura County (WCVC) for a study of projected climate changes in Ventura County. OVLC contracted with Drs. Nina Oakley and Ben Hatchett, climatologists with the Desert Research Institute (DRI), to evaluate historic climate variability and projected changes in Ventura County. This information is needed to “paint a picture” of future climate in the watersheds of Ventura County (Ventura River, Santa Clara River, and Calleguas Creek) to support and inform climate change-related decision-making. This study provides important information for the amendment to WCVC's Integrated Regional Water Management (IRWM) Plan
You can find a copy of the report on the DRI website at: https://wrcc.dri.edu/Climate/reports.php.
To view presentations and other information from the two WCVC Climate workshops conducted with Drs. Oakley and Hatchett in October of 2018, and April of this year please visit: http://wcvc.ventura.org/documents/climate_change.htm
Some of those most interesting findings for me, are the historical data. For example, data for the years 1896 – 2018, show a tendency toward increasing maximum temperatures over the period, especially the last 10 years (Fig 1.2). But most interesting, is the increasing minimum temperatures (Fig 1.3) as compared to the maximum temperatures. Winter where is thy sting? The 2018-19 winter was the coldest in my memory, with the heater on full time at night, but there was no general frost damage this year. I can remember 1990 and 2007.
Precipitation in the South Coast region exhibits high interannual variability over the period examined. No notable long-term trends are observed (Fig. 1.4). Since approximately 2000, the 11-year running mean decreases, associated in part with the 2012–2019 drought. It is unclear whether this trend will continue in subsequent years.
There's a lot more information in the report. READ On.
But something to keep in mind, is that we had a terrible heat wave last July, and it could easily happen again. Growers who had their trees well hydrated before the heat arrived, sustain less or no damage to the trees and much less fruit drop. Trees that were irrigated on the day it started to get hot, never had a chance to catch up with the heat. Once the atmosphere starts sucking the tree dry, water movement through the soil, roots and trunk cant keep up with the demand. Weather forecasting is pretty accurate 3 days out, and if heat is forecast, get those trees in shape. You can run water to reduce the temperature and raise the humidity in the orchard to reduce transpirational demand which helps some.
Something we learned last year. What we saw and what to expect:
Map of elevational changes in Ventura County and how
In the California agriculture industry, the climate change discussion is less about whether disruption is coming than it is about how farmers will adapt, reported John Cox in the Bakersfield Californian.
Cox spoke to a Delano farmer who doesn't like debating climate change, but he has thought a lot about how to deal with it.
"As a grower, you just take it as it comes," he said.
"Everybody I know in agriculture says, 'Yes, the climate's changing and adaptation to that climate change is crucial.' So that's not controversial," said Dan Sumner, director of the Agricultural Issues Center, a UC Agriculture and Natural Resources statewide program. "At the same time, that doesn't mean they buy into every public policy proposal for mitigating the climate change."
Climate change is likely to prompt farmers to grow different varieties or different crops.
But even as California agriculture may struggle to adjust to climate change, so will its competitors overseas, Sumner said. The real question is whether the state's farming climate will remain superior in relation to that of other countries producing the same crops, he said.
In the Washington Post, Adrian Higgins reported on the impact of climate change to agriculture across the nation. From Appalachia to North Carolina to California, milder winters are inducing earlier flowering of temperate tree fruits, exposing the blooms to increasingly erratic frost, hail and other adverse weather.
Breeders are working to develop new varieties, said Katherine Jarvis-Shean, a UC Cooperative Extension orchard systems advisor in Yolo County. But new trees typically take two decades of methodical breeding to create, exposing existing varieties to the vagaries of shifting winters and springs.
“The consumer will begin to know it's happening in the coming 10 to 20 years,” Jarvis-Shean said.
In a recent post about lemon shape being affected by high temperatures
a grower sent an image of what I thought was a blurred view of something that was circled. I responded saying that I couldn't make it out, and a better image should be sent.
The grower resent the image, but this time it was about the long yellow thing in the background that was being asked about. The tree is planted next to a chile pepper plant and the question was whether the shape was affected by the chile proximity.
The grower had never seen anything like it before and I haven't either. But rack it up to the high temperature wave during flowering and the rapid fruit growth period and hormones gone amuck. if temperature extremes become more common, unusual fruit shapes will likely become more common.