Strip-till farming is gaining in popularity in SJV

Two experts in the world of precision agriculture and minimal tillage kicked up some dust at the World Ag Expo in Tulare by emphasizing the value of conservation agriculture in leaving a legacy of better soil health.

Mike Petersen, lead agronomist with ANP Inc., headquartered in Moline, Ill., led off with what he called "A Quick Look at the Strip Tillage System," during which he was sharply critical of "beating the soil into submission while sending dust flying."

His talk, presented in partnership with California Ag Solutions, Sustainable Conservation and Power2Gro, was subtitled "Real Benefits Seen and . . . Not Seen."

Next came Jeff Mitchell, with the University of California, Davis, Department of Plant Sciences, who went global on the subject, pointing out that precision irrigation and conservation agriculture are being practiced around the world. He called for creation of peer group practitioners and better trading of information among growers in California.

Both men talked of improvement in soil health and savings in fuel and time that come with minimal till and strip tillage systems.

Both also likened the movement to conservation agriculture as akin to the space race of years ago. Petersen showed a slide that depicted a space launch and the words: "We are not initiating a shot into outer space. But we are lifting you up and out of the tractor seat to see a new perspective to farming, which will change the course of your way of growing a crop."

Petersen said inversion tillage—turning over soil repeatedly—has left a legacy that is not good. He said it has resulted in loss of vertical soil structure, a topsoil thickness of less than four inches, soil erosion, ponding and crusting, and reliance on big doses of nitrogen, phosphorous and potassium each year.

He said the conventional approach has also limited rooting of crops, slowed water infiltration and has "mauled and diminished worm populations."

With a strip-till system, he said, tilling is only where the plant root system starts in the soil: "We are not rolling, thrashing, exploding soil and creating ugly clods."

Petersen said strip-till brings a cooler soil environment for roots to grow and thrive, and less dust "is tossed into the atmosphere."

Less diesel fuel is consumed and less carbon dioxide is lost from soil carbon sources being oxidized. He said that, for every pass in California, 0.45 to 0.75 inch of water is lost, and passes have been reduced to one or two compared to four to seven with conventional tillage systems.

Petersen said economic considerations include savings in fuel, use of less fertilizer, reduction in time in the field, fewer trips across the field to prepare a seed bed, less capital investment and less expense in repairs.

By not rolling and tumbling soil, he said, "we allow more medium and fine pore spaces." That results in improvement of water storage and water infiltration during rapid rain or large irrigation events. "Below ground soil pores stabilize and help the soil 'drink' better," Petersen said.

Over time, the percentage of organic matter in the strip-tilled fields increases, while it remains consistently lower for conventionally tilled fields.

Petersen showed that the inches of water per hour that infiltrates a field that is strip-tilled are significantly higher than for conventional fields.

He showed a slide of critters like earthworms and molds, fungi and slimes—many not visible to the naked eye—that release enzymes, acids and phenols to break down complex carbon materials in organically diverse, strip-tilled soil.

"Crop quality improves and dairy cows eat better and produce more milk, which is something a dairy farmer does see," Petersen said.

Mitchell made the point that alternative cropping systems "are not always an easy thing to do."

"Tough sledding" is the term he borrowed from his Michigan upbringing to describe the challenge of pulling equipment through a strip-tilled field.

He echoed Petersen's remarks about the improved carbon content and porosity of soil with a strip-till approach.

He pointed out that farmers in Canada have formed farmer peer groups to learn and exchange information on strip-till and other precision agriculture practices, and said he would like to see more of that process in California.

Mitchell acknowledged there is more of an emphasis on strip-till farming elsewhere in the United States—especially in the "I states" of Indiana, Illinois and Iowa—but said it is taking root in California after years of research at the West Side Research and Extension Center in Five Points.

He said he would like to see a peer group develop in California.

In Canada, the motivation to start a farmer peer group was spurred by a loss of publicly funded agricultural extension, a need for more personally tailored information, a realization that there was great expense to other farmers and awareness of other models from other parts of the world.

He said components of this outreach effort could include an underlying educational program, farmers expressing interest and stepping up to do demonstration evaluations, performance monitoring and sharing of information.

He said conservation agriculture is already in place on half of Canada's acreage, more than a quarter of the acreage in the United States and nearly 90 percent of Australia's.

Mitchell showed advances in low-till activity in Nebraska, Washington, Alabama and Brazil. He acknowledged adoption of the approach has been relatively low in California, but cited pioneers who include dairy operator Dino Giacomazzi of Hanford.

While his Five Points research has centered on cotton and processing tomatoes, Mitchell said growers in the San Joaquin Valley and elsewhere are looking more to crops important to dairy operations. They include triticale, wheat and corn.

He said a survey in California in 2004 showed just 1 percent of growers were using strip-till or no-till to produce dairy corn. By 2012, that number grew to 40 percent.

He showed slides that included the first harvesting of winter forage wheat at the same time there was strip-tilling and planting of corn in Tipton.

Mitchell also encouraged use of center pivot irrigation systems, embraced by growers including Fresno County's John Diener.

(Dennis Pollock is a reporter in Fresno. He may be contacted at agcompollock@yahoo.com.)