Hexbyte Glen Cove Coastal grape growers can use less water during drought thumbnail

Hexbyte Glen Cove Coastal grape growers can use less water during drought

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A new study from UC Davis researchers sheds new light on how vineyards can mitigate drought effects at a time when California is experiencing a severe water shortage. Credit: Greg Urquiaga / UC Davis

California grape growers in coastal areas can use less water during times of drought and cut irrigation levels without affecting crop yields or quality, according to a new study out of the University of California, Davis.

The findings, published today (Sept. 1) in the journal Frontiers in Plant Science, show that vineyards can use 50% of the normally used by crops without compromising flavor, color and sugar content.

It sheds new light on how vineyards can mitigate drought effects at a time when California is experiencing a severe water shortage and facing more brought on by , according to lead author Kaan Kurtural, professor of viticulture and enology and an extension specialist at UC Davis.

“It is a significant finding,” Kurtural said. “We don’t necessarily have to increase the amount of water supplied to grape vines.”

Growers will also be able to use this information to plan for the next growing season. “Everybody’s worried about what’s going to happen next year,” he said.

Kurtural and others from his lab studied irrigation and cabernet sauvignon grape quality at a research vineyard in Napa Valley over two growing seasons, a rainy one in 2019 and a hyper-arid one in 2020.

They focused on crop evapotranspiration, which was the amount of water lost to the atmosphere from the vineyard system based on canopy size. The weekly tests used irrigation to replace 25%, 50% and 100% of what had been lost by the crop to evapotranspiration.

Researchers found that replacing 50% of the water was the most beneficial in maintaining the grape’s flavor profile and yield. The level of symbiotic arbuscular mycorrhizal fungi, which help grapevines overcome stresses such as water deficits, was also not compromised. And the water used to dilute nitrogen application was also reduced, making the process more environmentally friendly. 

The water footprint for growing grapes also decreased. For both the 25% and 50% replacement levels, water use efficiency increased between 18.6% and 29.2% in the 2019 growing season and by 29.2% and 42.9% in the following dry year. 

While focused on cabernet sauvignon, most red grapes will respond similarly, he said.  

“In the end, drought is not coming for wine,” Kurtural said. “There doesn’t need to be a tremendous amount of for grapes. If you over irrigate in times like these, you’re just going to ruin quality for little gain.”



More information:
The Bipolar Reset Experiment (BIRX) was conducted at Site 300., Frontiers in Plant Science (2021). DOI: 10.3389/fpls.2021.712622

Citation:
Coastal grape growers can use less water during drought (2021, September 1)
retrieved 1 September 2021
from https://phys.org/news/2021-09-coastal-grape-growers-drought.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove Coastal permafrost more susceptible to climate change than previously thought thumbnail

Hexbyte Glen Cove Coastal permafrost more susceptible to climate change than previously thought

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Micaela Pedrazas (left) and Cansu Demir, both graduate students at The University of Texas at Austin Jackson School of Geosciences, examining an exposed side of an ice wedge polygon, which was uncovered by erosion and melting. An ice lens is visible to the right of Demir. Credit: Bayani Cardenas

If you flew from the sea towards the land in the north slope of Alaska, you would cross from the water, over a narrow beach, and then to the tundra. From the air, that tundra would look like a landscape of room-sized polygonal shapes. Those shapes are the surface manifestations of the ice in the frozen ground below, a solidified earth known as permafrost.

Scientists long believed the solid permafrost extended offshore: from the , below that narrow beach and below the seafloor declining at a gentle slope. They viewed that permafrost like solid brick, locking the subsurface—and the vast amounts of carbon it holds—in place.

But new research led by Micaela Pedrazas, who earned her masters at The University of Texas at Austin Jackson School of Geosciences working with Professor Bayani Cardenas, has upended that paradigm. They found permafrost to be mostly absent throughout the shallow seafloor along a coastal field site in northeastern Alaska. That means carbon can be released from coastline sources much more easily than previously thought.

The study was published in Science Advances on Oct. 23 with coauthors from the Jackson School and UT’s Marine Science Institute.

Using a geophysical technique called imaging, the researchers mapped the subsurface beneath Kaktovik Lagoon along the northeastern coast of Alaska over the course of three years.

An aerial image of ice wedge polygons next to Kaktovik Lagoon. The polygons are signs of ice in the frozen ground below, a solidified earth known as permafrost. Credit: Nathan Sonderman

The results were unexpected. The beach and seafloor were entirely ice-free down to at least 65 feet. On the tundra itself, ice-rich permafrost was detected in the top 16 feet, but below that, the subsurface their imaging mapped was also ice-free.

“This leads to a new conceptual model,” Pedrazas said.

Permafrost is found in that remain frozen during the course of the year. Scientists have been tracking the impact of a warming climate on permafrost because as it melts, permafrost releases its stores of frozen carbon into the atmosphere as methane and , contributing to climate change.

Permafrost studies have almost exclusively focused on the region beneath the tundra. Because it’s not easy to work in such remote locations and under harsh weather conditions, the transition from sea to shore has been largely ignored.

“This study tells us that the coastline is much more complicated than we thought,” said co-author Jim McClelland from UT’s Marine Science Institute. “It opens up the possibility for routes of water exchange that we weren’t thinking about.”

Ph.D. student Cansu Demir and Professor Bayani Cardenas, both from The University of Texas Jackson School of Geosciences, installing a mini-groundwater well in the bed of Kaktovik Lagoon. Credit: Micaela Pedrazas

Besides global considerations, the work has local impacts. The communities along the coast, most of whom are Inupiat, live on the permafrost. As the permafrost thaws, it accelerates , which carves away at the land on which homes and infrastructure stand. In the Kaktovik region, erosion can be as great as 13 feet per year.

“Their cultural heritage and their welfare is integrated and intricately linked to their environment,” Cardenas said. “There’s an immediate need to understand what’s happening in these lagoons.”

The new paradigm requires reimagining the coastal Arctic ecosystem as well. Liquid groundwater means that carbon and nutrients can move between the tundra and the lagoon. It also means that saltwater can move beneath the tundra, potentially affecting freshwater sources.

Paul Overduin, who wasn’t involved in the research, but who studies permafrost at Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, said that this work is the first step in understanding ‘s transition from sea to shore.

“As is often the case, when we start looking at something people don’t know much about, you open up a whole bunch of questions that needed to be looked at,” he said. “That’s what’s really exciting here.”



More information:
“Absence of ice-bonded permafrost beneath an Arctic lagoon revealed by electrical geophysics” Science Advances (2020). advances.sciencemag.org/lookup … .1126/sciadv.abb5083

Citation:
Coastal permafrost more susceptible to climate change than previously thought (2020, October 23)
retrieved 26 October 2020
from https://phys.org/news/2020-10-coastal-permafrost-susceptible-climate-previously.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.