Category Archives: weather

Organic Tomato Farm’s Soils Produce High Yields During Terrible Drought

Today’s post is reprinted by permission of Charles M. “Chuck” Benbrook, who is a research professor at the Center for Sustaining Agriculture and Natural Resources at Washington State University.

Long-time readers of this site know that healthy organic soils retain moisture far better during drought-stressed conditions. Today’s post offers a pretty profound example of that principle in action this past summer during California’s drought.

Charles Benbrook reports about an organic tomato farm in California and its amazing success even during last summer’s terrible drought. The numbers he includes in this article of tomato yields and rainfall are astounding in a positive good-news way for producers of every kind, everywhere. He attributes this tomato production “miracle” to the organic soil health of the long-standing farm. (Although, I suspect because it is “Northern California-coastal” it is also receiving some moisture in the way of fogs.) Then, he warns growers that if they wish to be resilient in future weather-stresses expected from climate change, they need to establish similar soils in their own growing fields.

It’s a win-win.

Better tasting tomatoes, lower input costs, and crop resiliency.

It is better to let Nature do the work for us, instead of destroying the natural systems and then repairing the damage to get the yields we’re after.
—Kay M.


Promoting Global Food Security One Crop of Tomatoes at a Time

By Chuck Benbrook

In early September I visited a remarkable organic farm on the coast of California. This farm has been in organic production for about 30 years, and its harvests of mostly organic tomatoes have been marketed through a variety of outlets in Northern California.

I arrived on the day picking had just begun on a sloping tomato field about 6 acres in size. The crop was exceptionally clean, with virtually no insect damage and few weeds. Minimal, organically approved control measures had been used, including applications of sulfur and releases of trichogramma (beneficial wasps), along with many hours of hand weeding.

One of every dozen-plus fruits had minor, cosmetic blemishing on the skin, typically where the tomatoes contacted the soil. Otherwise, the tomatoes were picture perfect. I can also vouch for their organoleptic quality, from a first-hand eating experience at a dinner during my stay. These tomatoes also, no doubt, contain markedly higher levels of health-promoting phenolic acids and Vitamin C, for reasons discussed in an earlier blog (“A Tale of Two Tomatoes,” February 23, 2013).

The grower has since reported that the field produced about 30,000 pounds of tomatoes per acre.

Farmers in other tomato-producing regions often produce substantially more per acre.  My friend and colleague Madeline Mellinger runs Glades Crop Care (GCC), South Florida’s major independent crop consulting firm.  She and the GCC staff scout and advise farmers on pest management across about 11,000 acres of tomatoes each year.  In their neck of the woods, conventionally grown tomato yields average 50,000 pounds per acre, and in all but unusual years, range from 35,000 to 65,000 pounds/acre. Yields of 60,000 pounds per acre are common.

So what’s the big deal about a 30,000 pound per acre organic tomato yield in sunny California, when Florida (and some other California) growers often produce twice that per acre?

This was a dryland field of organic tomatoes – no, none, zero supplemental irrigation had been applied.  The field was planted in April.  Detailed weather data is accessible from a nearby weather station, which I accessed upon return to my office.

On August 6th and 7th, the last measurable rainfall had fallen in the area (0.02 inches, or two one-hundredths of an inch, i.e. almost none).  July rainfall totaled 0.16 inch, and 0.04 inch fell in both May and June. A far-below average 0.45 inch fell in April, and only 1.12 inches came in March, usually one of the year’s wettest months.

Total precipitation for the 2014 production season was 1.83 inches.  On California’s irrigated fresh market tomato fields, around 30” of irrigation water is applied to bring a crop to market, and according to the USDA, average yields are about 35,000 pounds per acre.

Organic production + 1.83 inches of rainfall = 30,000 pounds of tomatoes.

Conventional production + 30 inches of irrigation water = 35,000 pounds of tomatoes.

If a drought-weary California is forced to look for new ways to conserve water, the performance of this organic farm is both impressive and hopeful, given that it produced over 16,000 pounds of tomatoes per inch of rainfall.  On a typical, irrigated, fresh market tomato field in California, experienced growers harvest about 1,200 pounds of tomatoes per inch of irrigation water, and somewhat less than 1,000 pounds per inch of rainfall-plus-irrigation water.

How could 30,000 pounds of tomatoes per acre be harvested on a field receiving so little rainfall?

It’s all about the soil. Over the last 30-plus years, this field has been in a complex rotation, with ample amounts of added organic material and routine cover cropping. The organic matter content of the soil has been increased about two-fold – from around 1.5% to about 3% — promoting rapid water infiltration (when it rains), as well as enhancing the soil’s water holding capacity.

So what does this un-irrigated, organic tomato field have to do with feeding the world?

Governments around the world are urging people to increase consumption of fruits and vegetables to at least four servings per day (the USDA recommendation is 5-8 servings/day). The population of California is currently 38 million, so each and everyday, the good citizens of the State should be consuming at least 152,000,000 servings of fruits and vegetables.  Surely, mankind does not live by tomatoes alone, but for the sake of making an important point, bear with me.

According to the USDA, one serving of fresh tomatoes weighs 90 grams, or 0.19842 pound (i.e., there are about five servings in one pound of tomatoes).  Accordingly, 1,005 acres of similarly managed, organic tomatoes yielding, on average, 30,000 pounds per acre, would produce enough tomatoes to feed 38 million Californians four servings of this vegetable for one day.  Year-round, at the same yield level, only 366,943 acres would be needed to assure 38 million Californians get their four servings of fruits and vegetables a day.

The surface area of California is about 101 million acres, of which about 30 million acres are classified as farmland.  About 6 million acres in California are regarded as “prime” farmland. Over 500,000 acres of California land are planted to cotton most years, and another 1.5 million produce hay.  Clearly, finding 366,943 acres to produce enough fruits and vegetables (F+Vs) for all Californians should not be a major problem, at least not for a very long time.

For 314 million Americans, and the 7 billion on Planet Earth, less than 3% of available, high quality agricultural land would be required to assure production of at least four servings of F+Vs a day, per capita, year round.

Doing so, and getting the tomatoes, citrus, berries, and potatoes to the people who need them, including the poor, remains an enormous challenge, but not because of land shortages, lower yields on organic farms, or even persistent drought. In years when drought, or too much rain and flooding, or an untimely freeze, reduces fruit and vegetable production in one region, other areas can pick up at least some of the slack.  And through new methods to preserve and store F+Vs, the nation could (and probably will someday) create a strategic F+V reserve.

As climate change and severe drought become more commonplace, the importance of building soil quality as a hedge against catastrophic crop failure will grow.  Experience and insights gained on long-term, well-managed organic farms will provide a benchmark of what can be accomplished and how healthier, richer soil can serve as a buffer against climate extremes. And this will promote global food security, one field at a time.


Photo via FlickrCC Mr.TinDC.

3 Picks: SD Cattle Catastrophy, Japan’s Groundwater, Sustainable Barn


Below, are today’s three chosen agricultural-related news picks.

1) Catastrophic Early Snowstorm Kills Thousands of Cattle in South Dakota: By Chet Brokaw. “‘It’s the worst early season snowstorm I’ve seen in my lifetime.’ Early estimates suggest western South Dakota lost at least 5 percent of its cattle. Some individual ranchers reported losses of 20 percent to 50 percent of their livestock.’ …”

2) Japanese Municipalities’ are Creating Initiatives to Conserve Groundwater: By Junji Hashimoto. In Japan, where they have been using more groundwater since the 2011 earthquake, farmers and municipalities are working together and creating ordinances to use groundwater in conjunction with monitoring recharge rates. Through methods of cooperation, and a recharge calculation formula which reduces water fees when greater amounts of groundwater are recharged, they are smartly planning for the future.

3) UK’s Award-winning eco-build slashes thousands from farm’s running costs: “…by combining modern technology with traditional materials like sheep fleece and straw, it is possible to create a sustainable rural building that not only has a very low carbon footprint it is also saving many thousands of pounds in running costs. … Materials used in the construction and for running the building were sourced from the fields of the Allerton Project farm, including straw for the walls and sheep fleece for insulation. Wood chip harvested from the estate’s own woodland provide fuel for the biomass boiler to heat the hot water and the thermostatically zoned under-floor heating. Rainwater is collected for the toilets and showers, while sixteen roof-mounted solar photovoltaic panels provide electrical power to the building…”

This news post was written and compiled by K. McDonald.

Photo credit: Game & Wildlife Conservation Trust

CIRES and NOAA on the Boulder Flood Event

I’ve been waiting for this. Today, CIRES at the University of Colorado, NOAA, and the CSU Colorado Climate Center have released their preliminary assessment of the September 2013 Colorado Front Range flood event.

Key Points:
● An unusually persistent and moist weather pattern led to rainfall totals from September 9th – 15th that have been observed in only a handful of events on the Front Range in the past century.

● In the context of the entire Front Range this was a rare precipitation event, especially for September, and in some respects unprecedented.

● The very heavy rains caused severe to extreme flooding across the northern Front Range and downstream areas in northeastern Colorado; the peak flows at many gages and the overall extent of flooding were probably unmatched in at least 35 years.

● Research is underway at CIRES and NOAA to determine how human-caused climate change may have influenced this event and whether the risk of similar events occurring in the future will increase. The most plausible influence of climate change: Slightly more water vapor being made available for precipitation.

● The natural hazard of flooding for the Front Range includes not just smaller-scale convective events with very high rainfall intensity (e.g., Big Thompson, July 1976), but also rain-on-deep-snowpack events (May 1894), and broader-scale, long-duration rain events with mainly lower intensities (September 2013).

● Total societal exposure to flooding on the Front Range has increased in the past several decades due to population growth and development; recurrence of a previously experienced natural hazard will tend to cause comparatively more damage.

Martin Hoerling of NOAA in Boulder says that conditions for both Hurricane Sandy and this Colorado Flood had a blocking pattern that kept the weather from moving west to east as normal. How quickly a storm leaves an area is a big factor in the severity of any weather event.

UPDATE: Also recommended: The flood next time, by Roger Pielke Jr. who says, “Unfortunately, Time magazine set in motion an urban legend when it called our disaster a 1000-year flood, suggesting that it was an incredibly rare event, on with only 0.1 percent chance of occurring in any year. The claim subsequently has been repeated often across social and mainstream media. We cannot afford to get caught up in such hyperbole. What we know so far is that the flood event experienced by the city of Boulder, despite the record extent and magnitude of rainfall, is actually probably more accurately described under standard methods of flood frequency analysis as a 25-year flood, or one with a 4 percent chance of occurring in any year.”

Tremendous future growth is predicted for the Front Range of Colorado. Each weather event here, and elsewhere, is complicated by the expensive fact that more homes, roads, bridges, and supply chain infrastructure are damaged as growth trends upward.

SOURCE: http://wwa.colorado.edu/resources/front-range-floods/assessment.pdf