UC Delivers

Conservation Tillage Production Generates Less Dust

The Issue

The US Environmental Protection Agency designated the San Joaquin Valley (SJV) a serious non-attainment area for PM10, particulate matter with an aerodynamic diameter less than 10µm. PM10 can bypass the body’s respiratory defense mechanisms and has been linked to cardiac and lung diseases. Because air quality violations occur during periods of intense tillage activity, row crop agriculture has been pinpointed as a major contributor of PM10. Conservation tillage (CT) production systems that reduce or eliminate tillage have been developed in other regions. Less than 2 percent of California’s annual acreage uses CT approaches. Do CT production practices reduce dust and can they be developed for California crops?

What Has ANR Done?

In a variety of studies in the SJV starting in 2002, UC scientists compared dust generation in standard tillage (ST) and CT systems. In a comparison conducted at Five Points, Calif., dust emissions were reduced by about two-thirds in the CT system relative to ST through a cotton-tomato rotation. CT yields were maintained in this study for tomatoes, but were lower for cotton, primarily due to reduced crop stands. Work at two SJV dairy farms from 2003 to 2005 showed that CT corn and winter forage systems also may reduce emissions and that yields can be maintained for some CT approaches relative to ST. Initial findings indicate significant potential of CT production practices to reduce dust generation in common SJV cropping systems. UC researchers are working with valley farmers to improve the productivity and overall profitability of these and other CT systems.

The Payoff

Less dust from conservation tillage

Because of this work, SJV farmers are becoming aware of potential air quality benefits that may derive from CT. While CT currently is used on less than 2 percent of SJV annual crop acreage, UCANR's CT Workgroup has tracked increased use of CT practices during the past four years. The workgroup has been involved in more than 60 farm demonstrations, and its membership has grown from a handful of researchers in 1998 to over 540 UC, NRCS, farmer, private sector, and other public agency and environmental group members today. Access CT Workgroup information at http://groups.ucanr.org/ucct/.

Contact

Supporting Unit: UC Davis Department of Plant Sciences - CT Workgroup

Jeff Mitchell, CE Specialist, Department of Plant Sciences, UC Davis, mitchell@uckac.edu
Randal Southard, Professor,
Department of Land, Air and Water Resources, UC Davis, rjsouthard@ucdavis.edu