Farmers describe organic, no-till vegetable production

Three California farmers gathered virtually for a report on two years of research in commercial-scale, no-till, organic vegetable production. The farmers discussed experiments supported by Conservation Innovation Grants offered by the U.S. Department of Agriculture.

Topics included cover-crop biomass digestion under plastic and weed barrier fabric, carbon-to-nitrogen ratios, novel equipment and cover cropping.

Scott Park, his wife, Ulla, and son, Brian, farm 1,700 acres with 10 to 20 different crops south of Meridian for Park Farming Organics. In discussing reduced tillage for organic farming, he said growers need to match their cover crops to their farming system.

"Trust your own instincts," he said. "Believe what you see."

He advised using legumes as cover in early spring, and a mix in later spring.

Park discussed difficulties with cover crops in tomatoes and recommended "changing the farm system in small increments."

"You need to have miscellaneous equipment that fits your farm, not fitting your farm to available equipment," he said, and referred to his operation as "a normal California farm, farmed abnormally."

Machinery he uses includes a vertical disk to mix the cover crop with the soil, and a cutting bar that slides through the bed to lift the plant. He said a minimum-tilled field can be ready for planting in two weeks, and it can be a mistake to plant too soon after tilling.

Park also incorporates animal grazing into his system, and uses a flamer to control weeds. He said nature adjusts to man's intervention and, to illustrate that, he showed a picture of a tree that had grown around a tractor, engulfing much of it.

"How do you flow with nature and not have nature fight back?" Park asked.

Paul Muller, co-owner of Full Belly Farm in the Capay Valley, grows 80 crops in rotation along with products produced with the help of chickens, sheep, goats and several cows.

Muller cited five rules for healthier soil with reduced tillage: avoiding or reducing tillage, including chemical intervention; keeping living roots in the soil; creating diversity of plant species for cover crops; keeping soil covered with mulch; and introducing animals if possible.

He said the conservation grants help farmers look for techniques for growing vegetable and tree crops with reduced- or no-till practices and tool up to grow quality crops while enhancing soil fertility.

Full Belly Farm is also looking at the impacts of keeping ground covered and changes in the soil after three years while measuring organic matter, carbon, water-holding capacity and fungal/bacterial ratios, and nitrogen cycling and availability, while assessing yield and quality.

Muller acknowledged setbacks with certain crops, including melons, which yielded at 30% of comparable melon crops. Questions that were raised include whether melons like the mix of living covers on the side of the plant line, Muller said, and "did we mix soil in the seed line and change the decomposition process?"

Phil Foster and Katherine Foster farm 250 acres of certified organic fruit and vegetables on two ranches near San Juan Bautista and Hollister. They have a diverse range of crops and market up to 60 produce items at peak season.

Phil Foster said undercutting with a McElroy machine has proved successful in terminating cover crops. He described tools important in reducing tillage, including a roller-crimper and a vertical tillage tool and strip tillers to manage residue, along with power harrows and spaders. He said crimpers don't always kill cover crops that can compete with crops such as melons, but undercutting addressed that.

Foster has used plastic cover in his system for growing watermelons, showing increased moisture and higher yields. Plasticulture facilitated more stable soil aggregates, he said, and showed increases in total nitrogen, nitrates, ammonium, inorganic nitrogen, organic matter, available nitrogen, phosphorous and nutrient value. He said he plans further research on plasticulture usage.

During a question-and-answer session, Tom Willey, a retired farmer of a 75-acre patch in Madera, said he has been an advocate of using plastics and joked that he has been accused of being "a plastic salesman sometimes."

Willey called plastic an excellent moisture barrier "to hold a very humid environment against the soil on top of which we have left a great deal of biomass."

He conceded "we're not happy with using plastics," and they must be removed from the field. He said there will be experiments with biodegradable plastics and research into whether those can be composted.

The program was presented by the Ecological Farming Association.

For more information about Conservation Innovation Grants, which are offered by the USDA Natural Resources Conservation Service, see the NRCS website at www.nrcs.usda.gov; find the Programs tab, then choose Financial Assistance.

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