Climate change puts spotlight on cannabis drought-resistance claims

Posted on January 6th, 2020 by Bill Weinberg and tagged , , , , , , , , , , , , .

cannabisZambia becomes the latest African country to legalize cannabis cultivation—in the midst of a shriveling drought that has caused massive crop failures. The landlocked republic could be an unwilling test case in whether cannabis is as effective a drought-resistant crop as its boosters claim.

Last year closed with another country joining the growing list of those that have embraced commercial cannabis cultivation: the landlocked southern African republic of Zambia.

Legal cultivation—amid devastating drought
The decision was made in an early December special cabinet meeting to legalize production and export of cannabis for the medical market.  It was announced two weeks later, to much fanfare in Africa's media. The move, taken in response to a yawning fiscal deficit and growing debt burden, makes Zambia the fifth nation on the African continent to permit cannabis cultivation.

The leader of Zambia's Green Party, Peter Sinkamba, applauded the decision. He was quoted by Nigerian news site Sahara Reporters saying the move could earn Zambia up to $36 billion annually. "Depending on how properly this is done, this could just change the face of Zambia's economy," Sinkamba said.

Authorities are making it clear that personal possession remains a crime. President Edgar Lungu warned Zambians that those who smoke cannabis will still be subject to arrest.

But the country's own health minister—who will have authority for granting licenses—is reported to already be getting into commercial cultivation himself. The website Zambian Watchdog reports that Health Minister Chitalu Chilufya and a business partner are currently preparing cultivation sites in the central districts of Chisamba and Makeni.

However, the move also comes as Zambia is experiencing its worst drought in a century. As world leaders gathered in Madrid for the UN Climate Summit last month, southern Africa was already experiencing some of the harshest impacts of global warming—with some 45 million people in need of food aid amid crop failures.

Reports from the Zambezi River Authority indicate that water flow at Victoria Falls is at its lowest since 1995—far below the long-term average. President Lungu said his country's drought is "a stark reminder of what climate change is doing to our environment," according to Reuters.

How drought-resistant is cannabis really? 
There was much boosterism about the hearty nature of the cannabis plant as hemp legalization approached in the United States over the past two years—finally achieved with passage of the Farm Bill in December 2018. Advocates boasted that a hemp field can be grown to harvest on about half as much water as needed by an equivalent plot of corn.

"It uses more water at the very beginning of its growth," Geoff Whaling, chairman of the National Hemp Association, told the Pacific Standard in May 2018. "But once it kind of passes its early development stage—about three weeks—it becomes one of the most drought-tolerant crops on the planet."

But (surprise!) while hemp purveyors boost the crop as drought-resistant, contrary claims are put forward by peddlers of irrigation equipment.

The newsletter of the Nebraska-based irrigation equipment company Reinke asserts in a headline: "Irrigation Proves Essential in Hemp Production." It cites a May 2018 report in Hemp Industry Daily on the findings of a Colorado State University study, that irrigated hemp produced nearly three times more seed than non-irrigated hemp.

Brian Campbell, a doctoral student in soil and crop sciences, grew two test plots at a northern Colorado site—one irrigated consistently; the other receiving only some eight inches of rainfall throughout the growing season. The irrigated plot produced an average of 1,100 pounds of seed per acre, while the non-irrigated one produced about 400 pounds per acre. Campbell’s research led him to conclude that hemp’s water use is actually high compared to other crops, according to Reinke.

"There are a lot of myths about this crop, and one of them is that it doesn’t need much water," Campbell told Hemp Industry Daily. "It's not that the plant won’t grow" without much water, he elaborated. "But it’s a no-brainer—you should irrigate your hemp plants if you want them to do well in Colorado."

The report additionally cited a study by the Purdue Hemp Project at Indiana's Purdue University, finding that most varieties of hemp need 25-30 inches of rain per year. But Purdue also emphasized that due to the plant's long illegality, "large information gaps" persist on its viability in different environments.

A nice irony is that the line of the hemp-boosters has long been heard from law enforcement voices who seek to protray cannabis as an insidious menace. "Marijuana is a very drought-tolerant plant. It's a weed, and they grow anywhere," DEA agent Bill Weinman told Denver's Rocky Mountain News during a dry spell in 2002. "Drought has little effect on pot crops. Plants prove hearty, surpassing yields of state's other crops."

An account on the perennially lurid Vice in 2015 even asserted that "Climate Change is Making Weed Stronger." It dredged up a 1988 Associated Press story about the seizure of unusually healthy plants in Virginia—again, during a drought. The reporter interviewed Virginia Tech researcher Larry Moore, who speculated that cannabis plants stressed by lack of water could become more potent. 

Success with dry-farming
Cultivators of both hemp (non-psychoactive cannabis) and marijuana (psychoactive varieties) have long maintained that some strains are more drought-resistant than others. The website of Barcelona-based Royal Queen Seeds particularly names the indica-sativa hybrid known as "Critical," popular across the Mediterranean, as sought among outdoor growers for being "very tolerant of high temperatures and dry weather conditions." 

Certainly, marijuana growers have met with success in "dry farming" techniques—that is, cultivation without irrigation. Dry farming is increasingly practiced in Mediterranean climates, with wet winters and dry summers. In climes that get rain year-round, irrigation is not an issue; whereas in an outright desert, irrigation-free cultivation is an impossibility.

Mediterranean climates include California, and dry-farming of cannabis is catching on in the Emerald Triangle as a part of the general trend toward sun-grown and organic product. Cannabis Now in October 2018 featured an interview with the cultivators at Sunboldt Grown, which began dry-farming a year earlier on its lands in Holmes Flat, Humbold County.

“Dry farming is not for the faint of heart,” admitted Sunboldt Grown's Sunshine Johnston, recalling her fears as she saw her plants suffering under the hot summer sun. But she resisted the temptation to water them, and the results were very satisfactory—high-resin yields with up to 30% THC.  

"I think what I learned last year is that plants actually prefer less water and no fertilizer," she said. "They really prefer to be on their own." 

Diversion of water for illicit cannabis cultivation has long been a strain on Northern California's watersheds, threatening the survival of salmon and other local wildlife. This is also now an issue for the legal cannabis sector. And the evidence of aridifying conditions could hardly be more dramatic. Cannabis grows have been impacted by California's devastating wildfires over the past two years, and officials in the state now admit there is no longer a "fire season"—it is has become a year-round phenomenon. The nearly apocalyptic conditions now seen in bushfire-devastated Australia also appear to be a grim harbinger of things to come. In the coming years, it will certainly be a challenge for cultivators worldwide to figure out new ways to grow cannabis with less water.

Cross-post to Cannabis Now

Photo by WikiMedia


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