The
unrelenting heat and lack of significant rainfall that settled over much of the
country this summer made the 2012 drought the worst to hit the United States in
half a century. By the end of July, more than 60 percent of the continental United
States was experiencing moderate to extreme drought.1 The average
monthly temperature for July was slightly higher than the all-time record set
in 1936, when the country was enveloped by the Dust Bowl, making it the hottest
month since records began in the late 19th century.2 August
was equally unforgiving, with the National Oceanic and Atmospheric
Administration (NOAA) citing it as the fourth hottest August since 1880 and the
330th month in a row with warmer-than-average global temperatures
for the 20th century.3
As
the season changes and temperatures begin to drop, the drought is less prominent
in the minds of Americans, but months of above-average temperatures and sparse
rainfall have caused irreversible damage to some crops — notably corn (Zea mays) and soybeans (Glycine max). Plants have remarkable
defense mechanisms, however, equipping them to survive less-than-ideal
conditions, so consumers likely will not face any widespread shortages of
plant-based products in the near future. Still, wholesale prices for some US medicinal
botanicals such as goldenseal (Hydrastis canadensis)
and ginseng (Panax quinquefolius)
have begun to rise and other price increases are expected.
“Any and all crops [for] medicinal, food, or
other uses are being impacted in the areas of the drought,” said Edward
Fletcher, of Strategic Sourcing, Inc., a botanical supply company that
specializes in quality control, research and development, and connecting clients
to herbal suppliers (email, August 28, 2012). “Some of the cultivated crops can
be irrigated which can help mediate the impact, but this additional
labor and expense will add more cost to the end product. Even with
irrigation, which cannot completely replace natural rainfall, the yields
per acre or hectare will be down, so this will affect prices.”
How Plants Respond
to Drought Stress
In periods of extreme or prolonged heat, plants
restrict water use to maintain processes that are essential to survival.
“When plants, particularly perennials, are adversely affected, they
respond defensively just trying to survive, so they shut down, so to speak, in
many different ways to protect themselves,” said Fletcher.
Soybeans
are one of the United States’ leading agricultural exports and, of all the
medicinally useful plants, the most data exists for this economically important
crop. Although usually seen as a food crop, a small portion of the world’s soy is
used in dietary supplements. According to recent econometric data, after
cranberry (Vaccinium macrocarpon), soy
is the second highest-selling single herbal dietary supplement in the United
States in the mainstream retail market.4 Brian Young, PhD, a
professor of weed science and agronomy in the Department of Plant, Soil and
Agricultural Systems at Southern Illinois University, described how soy plants respond to drought conditions.
"Soybean plants will rotate their leaves
under drought stress so that they have less leaf surface in direct sunlight
which can help reduce transpiration and water use. Under extreme drought the
lower leaves may prematurely senesce [age]
to restrict water use,” he said (email, August 24, 2012). “Soybean plants
will also respond by aborting flowers, seed pods, or individual seeds in
response to drought as well as producing smaller seeds than normal. The
specific response depends on the timing and duration of drought stress relative
to the soybean growth-stage."
Lack of water in particular can cause some
plants to have increased concentrations of secondary metabolites, many of which
have medicinal properties. The increase in these
compounds can improve a plant’s ability to defend against pests.
Chuck Wanzer of Botanics Trading LLC, a North
Carolina-based wholesale supplier of medicinal plants from around the world,
explained the potential benefits of drought-related stress. “Moderate drought
may actually increase the production of defensive compounds in plants. We do
drought stressing in growing Echinacea [Echinacea
purpurea] to increase the
actives when we cultivate,” he said (email, September 6, 2012).
Wanzer noted, however, that the stress caused by moisture loss also can
negatively impact the overall health of the plant as well as the growth of
specific plant parts. “This increased [compound] production can
also add increased protection against pests, [but] this is not universal as
moisture stress can make a plant more susceptible to insects and disease,” he said. “The
quality of herbs and leaves will be lower since the plant does not have the
energy to produce quality foliage or herbage. The root products will not be as affected
by drought. The root may be smaller, but it will be more concentrated due to
lack of water."
Although drought conditions vary from one region
to another and can affect plant species in different ways, some trends are
evident. Fletcher explained that the 2012 drought will have the greatest impact
on annual crops. And regardless of the species, plants will be smaller than plants growing during ideal weather conditions.
“Annual crops have only one season to grow to
harvestable sizes, so annuals will be the most adversely affected,” said Fletcher.
“Perennial crops that are established will be able to survive the drought
conditions better but still suffer, resulting in less-than-normal growth,
perhaps stunting them for years to come.”
Impacts on Medicinal Plants and Wild-Harvested Herbs
Although most available data examines cultivated
crops, drought conditions will also affect wild-harvested herbs, which experience
varying weather conditions depending upon geographic location.
“Wildcrafted botanicals are ‘weeds’ so
they are hardy plants and can [usually] adapt to drought conditions,” explained
Wanzer.
Although wildcrafted botanicals are often
hardier than cultivated crops, the less-developed aerial parts — like those of goldenseal — which
guide harvesters to the plant’s roots, will make them more difficult to find.
“Some
herbaceous perennials will simply die back early to reduce transpiration so
when the wildcrafter searches for them at the usual time of season he or she
may not be able to find them, resulting in shortage in
supply which generally increases prices,” said Fletcher.
Goldenseal — a medicinal plant that has traditional and folkloric uses
for colds, respiratory conditions, and diarrhea — has been
impacted by the drought for these reasons.5
“Goldenseal root production this year will drop slightly,” said Wanzer,
“but there will be very little goldenseal tops [aerial parts] harvested this
year.”
Fletcher noted that the drought’s effects on additional
wild-harvested herbs can already be seen. “Some of them are Scutellaria
lateriflora [skullcap],
Echinacea purpurea, Monarda didyma (which prefers moist conditions)
[Oswego tea], Hydrastis canadensis,
and Panax quinquefolius
to name a few,” he said. “We are concerned about several crops that are
showing the effects of the drought in terms of yields, but we really will not
know the full extent of the impact until they are harvested, cleaned, dried,
packaged, and weighed.”
Similarly,
Steven Foster, author, photographer, and chair of the Board of Trustees at the
American Botanical Council, noted a number of typically wild-harvested herbs
that will be impacted by the summer’s dry conditions. “Basically, in terms of
woodland herbs that are harvested in the Midwest and Eastern deciduous forest,
things like ginseng, goldenseal, black cohosh [Actaea racemosa] — much of their range was heavily stressed this
summer,” he said. “It meant that the vegetative period was relatively short so
the plants went back to root. That is, they went dormant earlier than they
normally would have. Then it got really hot, so I suspect fewer people were out
there harvesting.”
Allen Lockard of American Botanicals, a
manufacturer and seller of North American herbal products, said he expects the drought to impact skullcap
and saw palmetto (Serenoa repens) berries.
Because berries and other fruits require substantial water and energy, they are
particularly vulnerable to drought. “No water – no growth,” he said (email,
August 27-30, 2012). “[There will be] no berries because [there are] no
blooms.”
Yields Decrease While Prices Rise
Prices of drought-damaged plants are expected to
rise and, in some cases, have begun doing so. “I am already seeing prices for
skullcap increase due to crop failures in the areas of production along with Echinacea purpurea herb and root,” said Fletcher.
“Also American ginseng seed prices are spiking due to low [stocks of] seeds and
those that are available are testing with lower germination rates.”
The full extent of the impact on botanical
prices may not be known for some time. “The impact on
wild-crafted botanicals will be more difficult to appraise and may not actually
be noticed for years to come,” said Fletcher. “It will affect the seed
production for this season and this will not exhibit itself for years
either, depending on the lifespan of the species.”
Foster
explained that although there may be some shortages in select herbs, the relative
yield size of medicinal plant crops compared to soybeans, corn, or other major
US agricultural crops will limit the overall impact on the market.
“Most
[medicinal] plants [are] relatively short tonnage items,” he said. “There may
be a few hundred or a few thousand pounds of them harvested, but not anything
that would significantly impact the market or supplies in a measurable economic
sense, unless you’re looking at soybeans.”
The effects of the drought on soybeans can be
stated with more certainty due to records kept by government agencies such as
the United States Department of Agriculture (USDA). “The drought is definitely
impacting the expected soybean production for the Corn Belt and, thus, the
United States,” said Travis Thorson of the USDA’s National Agricultural
Statistics Service (NASS) (email, August 24, 2012). “You can tell from the September
1 soybean forecast where the US yield was forecast well below last year’s (35.3
bu/ac [bushels per acre] versus 41.5 bu/ac last year). This is largely due
to the drought.”
According to NASS statistics, soybean pod counts
are significantly lower than those from one year ago. “The September objective
yield data for the combined 11 major soybean-producing States … indicate a
lower pod count compared with last year, as hot, dry weather during bloom
hampered development of the crop in many areas,” wrote the authors of the
September 2012 Crop Production report.6 “Compared with final counts
for 2011, pod counts are down in all published States. As of September 2, 30 percent
of the United States soybean crop was rated in good-to-excellent condition, 26
percentage points behind the same week in 2011.”
As some corn crops have been abandoned or converted
to livestock feed due to unfavorable conditions, soybean crops may face a
similar fate in the hardest hit areas such as Nebraska and other states in the Farm
Belt.7 “It’s possible there will be a larger portion of the acreage
that will be abandoned this year as well, which would be reflected in a lower
Harvested/Planted ratio,” Thorson continued. “But that may not be truly known
until harvest is complete this fall.”
Amid the uncertainty, soybean prices have
increased since the beginning of the drought. “Monthly prices for soybeans have
increased the last several months as the drought has worsened,” said Thorson.
“The monthly prices at the US level that NASS publishes for the last few months
have increased from $13.00 for March to $15.60 which was our preliminary price
for July.”
The preliminary price of soybeans in August
increased slightly to $15.90 per bushel, marking the seventh straight month of
increased prices.8 More information about the extent of the
drought’s impact on American crops will be available in January 2013, when the
USDA releases its Annual Crop Production report.
Preparing for an Uncertain Future
Although it is not an option for wild-harvested plants,
irrigation is one of the only options to help counter the effects of intense
heat and lack of rain.
"Irrigation, which is limited to a small
fraction of US soybean acres, is the only practice that may help plants
overcome drought,” said Prof. Young. “If drought is anticipated annually, such
as having dry conditions in August, a grower may attempt to plant soybeans
earlier in the Spring so that the majority of soybean growth and reproduction
has occurred prior to the onset of drought conditions."
Lockard of American Botanicals says that
maintaining adequate inventory is essential in times when crop production is
threatened. However, he cautioned against exaggerating the potential effects of
the drought. “Every year some products are short and some are long,” he said. “Every
manufacturer should carry one year of stock. One thing worse than too much
inventory is [having] nothing to sell.”
As record heat and unpredictable weather patterns
continue, Fletcher advises manufacturers and distributors of botanicals to be
as prepared as possible. “This should be a warning to all purchasing arms that
some things are beyond our control,” he said. “So for botanicals that are
significant to their bottom line, they should consider stocking additional
material to prevent interruptions in production and loss of sales.”
Although yearly fluctuations in weather are to be
expected, trends toward warming and extreme conditions are not ideal for plant
cultivation and are especially a concern in the United States, where
agriculture is the country’s leading industry.
“Long term drought is the real problem,”
said Wanzer. “Plants are wonderfully resilient and can survive, but if the
drought conditions continue, then the plant becomes weaker and less able to
recover and regrow when conditions are better, and will finally
die. Climate change is the real game-changer as this is the continuing
condition that will change whole populations of plants.”
—Tyler Smith
References
2.
State of the climate, national overview: July
2012. National Oceanic and Atmospheric Administration National Climatic Data
Center website. Available at: www.ncdc.noaa.gov/sotc/national/2012/7. Accessed
August 31, 2012.
3.
State of the climate, national overview: August
2012. National Oceanic and Atmospheric Administration National Climatic Data
Center website. Available at: www.ncdc.noaa.gov/sotc/national/2012/8. Accessed
September 14, 2012.
4.
Blumenthal M, Lindstrom A, Ooyen
C, Lynch ME. Herb supplement sales increase 4.5% in 2011. HerbalGram. 2012;95:60-64. Available at: http://cms.herbalgram.org/herbalgram/issue95/hg95-mktrpt.html. Accessed September 28, 2012.
5.
Herbs at a Glance: Goldenseal. National Center
for Complementary and Alternative Medicine website. Available at:
http://nccam.nih.gov/health/goldenseal. Accessed: September 21, 2012.
6.
Crop production (September 2012). United States
Department of Agriculture’s National Agricultural Statistics Service website.
Available at: www.usda.gov/nass/PUBS/TODAYRPT/crop0912.pdf. Accessed September
21, 2012.
8.
Agricultural prices (August 2012). United
States Department of Agriculture’s National Agricultural Statistics Service
website. Available at:
http://usda01.library.cornell.edu/usda/current/AgriPric/AgriPric-08-31-2012.pdf.
Accessed September 21, 2012. |