Almond growers rely on research and technology to comply with myriad air quality rules

Editor's Note: This is the first in a three-art series on air quality issues affecting the California almond industry that ran in Western Fruit Grower

By Gabriele Ludwig

Senior Manager, Global Technical & Regulatory Affairs

Almond Board of California

July 2008

California almond growers farm some of the most fertile, productive ground in the world. Unfortunately, they also farm a region with some of the worst air quality in the nation.

Air quality regulations are changing the way almond growers farm, harvest and transport their crops, while adding considerable cost to the bottom line.

These rules, some of them pending and others already on the books, come from federal, state and regional levels and they are sometimes confusing, overlapping and even conflicting.  

Air quality regulations focus on three general kinds of air pollution: ozone, dust and greenhouse gasses.

Ozone: Fossil fuels and NOx

Ozone is the subject of intense scrutiny in the San Joaquin Valley. A component of smog, ozone is formed when nitrogen oxides (NOx) react with volatile organic compounds (VOCs) in sunlight. Agriculture has been tagged as a significant source of NOx and VOCs emissions and new regulations are now in place or on the table that regulate those ozone precursors.

Almond grower Tom Teixeira will be using cleaner burning electric irrigation pumps to operate a new micro-sprinkler system on 270 acres of newly planted almonds. (Photo by Marni Katz)

The largest source of NOx is fuel combustion, so any time a grower can reduce the number of passes, use newer, cleaner burning motors, or increase fuel use efficiency he is helping to reduce NOx emissions. Tom Teixeira of Teixeira and Sons in Gustine has installed a micro-sprinkle system powered with two new, lower-emission electric pump engines on a new 270-acre block of almonds. Many growers are also using newer harvesting equipment that reduce passes in the field or consolidate multiple operations.

Proposed state-wide rules targeting diesel emissions will also have an impact on NOx. The state Air Resources Board will require the retrofit of older diesel truck engines with diesel filters beginning in Dec 31, 2010. Starting in 2012, trucks will have to replace their motors with lower NOx emitting motors based on their age. By 2016 the entire fleet of pre-2006 heavy duty diesel trucks is to be retrofitted at an estimated cost of $20,000 each.

Similar rules for agricultural equipment, such as tractors and harvesters, are next on ARB’s regulatory agenda.

Ozone: Pesticides and VOCs

Volatile organic compounds are the second component in ozone, and pesticides have been identified as a contributor to VOC emissions in the San Joaquin Valley. Two groups of pesticides are considered major VOC emitters: soil fumigants and EC formulated pesticides. The Department of Pesticide Regulation in January passed a new regulation to reduce VOC emissions from soil fumigants.

These new rules will impact growers’ ability to do fumigations in the San Joaquin Valley during the peak ozone period from May to November by requiring lower emissions application methods for all soil fumigants.

The regulation also sets a cap for all pesticide VOC emissions.  To meet the cap, mandatory cuts to soil fumigant use will go into effect in 2009. How much soil fumigant is available under those caps will depend largely on the amount of emulsifiable concentrate (EC) pesticides were applied in the Valley two years prior. Commonly used almond pesticides, such as chlorpyrifos (Lorsban) and abamectin (Agri-Mek) are among the major pesticide VOC contributors, according to DPR data.

To address VOCs, growers wherever possible should avoid using EC pesticide formulation during the ozone season from May 1 though Oct. 31.  Pesticide manufacturers are in the process of developing alternative formulations for many commonly used products. But in most cases the newer formulations are expected to be more expensive and perhaps slightly less efficacious.

Researching Viable Alternatives

Almond growers through the Almond Board of California are funding research to develop cost-effective and viable alternative management practices that will help growers comply with VOC, NOx and other air quality regulations.

Two such projects focus on reducing the VOC emissions generated by soil fumigations.

At UC Davis, Ag Engineer Shrini Upadhyaya is looking at site specific fumigants using GPS to target fumigants to the site of a new almond tree rather than fumigate entire fields or strips, thereby reducing the amount of fumigant applied.  

Plant pathologist Greg Browne, with USDA’s Agricultural Research Service (ARS) in Davis, is researching alternatives to soil fumigants for orchard replant disorder.

In addition, Suduan Gao, an ARS soil scientist in Parlier, for four years has been comparing different soil surface amendments to traditional polyethylene tarp fumigations to see if she can develop workable alternatives to tarping.

“Our task is to quantify ways to help growers comply with new soil fumigant regulations by developing some practical methods that growers can actually afford to use,” Gao said.

She has determined that water seals, or applying sprinkler irrigation several times within 48 hours of a fumigation application, can create a seal around the fumigation site and reduce emissions.

“Whether water seals are practical or not depends on whether growers have a water supply and sprinkler system that can support it,” Gao said.

She is taking the principal of water seals, however, and exploring the use of soil additives and amendments that might provide the same advantage.

“We are working to determine if organic amendments, such as composted manure, can achieve the same or similar benefit,” she said.

# # #

# # #

Air Quality Issues Affecting California Almonds