Adoption of conservation tillage in general has been relatively slow in California, but some San Joaquin Valley dairy forage growers are enthused with results as they take a closer look at one element of the practice, strip tillage.
Dairyman Dino Giacomazzi was pleased enough with his two years of strip tillage to share his experiences and opinions at a recent field day, held in cooperation with the Conservation Tillage Workgroup, at his family's forage corn fields outside Hanford, Calif.
Conservation tillage systems include an array of equipment and methods intended to curb soil or wind erosion, increase water infiltration, reduce labor and fuel, increase soil organic matter or improve air and water quality.
Jeff Mitchell, University of California Cooperative Extension vegetable specialist, defined strip tillage — also known as vertical tillage — as a management system “that only disturbs the top 6 to 8 inches, maybe more or less, depending on the implement, of the soil surface.
“That is the line into which you will plant. Obviously, since you are not doing broadcast tillage, you are reducing some of the input costs and preserving residue on the surface.”
Mitchell noted that in California strip tillage is most often used for forage crops but is also being introduced in vegetable crops and cotton.
Several designs of strip-tillage implements are available, and all share three components: coulters to cut crop residue, shanks to break the soil surface and tools to break up clods and prepare the seed bed. Planters may be added for a single-pass operation.
In reviewing why he is involved in strip tillage, Giacomazzi told the assembly of some 130 growers and others that he was first attracted to it by Natural Resources Conservation Service incentives aimed at reducing particulate matter.
His initial attempt two years ago with 25 acres of forage corn with no-till, bringing in 27 tons to the acre, was not encouraging in view of his 30-ton yields from conventional methods.
“Environmental solutions should also be economic solutions. There has to be a benefit to the person who's implementing the technology,” he said.
Last year, however, the picture changed when he went to strip tillage on the same acreage and took off 36 tons to the acre, more than any of his conventional fields that season.
Strip tillage cuts costs, he said. “We reduced passes by 80 percent, we reduced diesel fuel and emissions, we used less equipment and labor, we got more tons per acre, and because it was quicker, we got in three crops per year.”
He listed a dozen conventional field operations for coming out of wheat, from ripping to lilliston passes, that he accomplished with two passes: strip tilling and planting.
Since he uses dry manure and lagoon water from the dairy for all his fertilizer needs, his conventional practices do not include a fertilizer application.
“It's easier for me with the dairy right here to adopt this method because I don't have to be worried with going back into the field with a fertilizer rig.”
He built borders, as for alfalfa, in the fields and will leave them in place for wheat, corn and sorghum, before repeating the cycle.
Giacomazzi stressed that managing on fields without low spots and with good drainage is key to making strip tillage a success.
He has a number of trials across his corn acreage this year with various brands of equipment and varieties. A portion of his strip tillage corn this year is planted to twin rows with a Monosem planter, rather than single rows.
“Twin row gives an opportunity to increase yield by increasing plant populations and giving plants more space and less competition for sunlight, nutrients and moisture,” he said.
On 30-inch rows, a single row of plants 6 inches apart has a population of 32,000 per acre, while the twin-row configuration staggers two rows has a population of 42,000 per acre and more space, 10 inches between plant rows and 13 inches diagonally, between plants.
He said it is essential to have a GPS guidance system aligned perfectly for success with twin row planting.
His irrigation timing was mostly by the calendar, but Giacomazzi said that in his conventional fields each irrigation took less time than the one before it. “But with the strip tilled fields, from the pre-irrigation to the final irrigation each took about the same amount of time. The ground is compacted between strips, so the water is concentrated to the roots in the strips.”
He irrigated the strip till corn about 10 days after emergence, or about 15 days earlier than conventional fields, and that gave the crop a significant boost in growth.
As for why California farmers have been slow to take up strip tillage and related methods, Giacomazzi said he believes the main reason is technology was not available until only recently.
“Strip tillers were in other parts of the country but they hadn't made their way out to California. And twin-row planters are relatively new here.”
GPS guidance systems for tractors are essential for strip till to work, he added. A fourth development is the availability of Roundup Ready corn varieties.
“Despite the fact that California has one of the most advanced agricultural economies on the planet,” he said, “we seem to be behind in many ways. I think that is because we are somewhat spoiled.” Spoiled, he explained, because of mild weather, historically ample water and historically inexpensive labor.
But that's changing, he added, with treats to water and labor supplies, increased fuel costs, environmental regulations, demands from consumers with no knowledge of agriculture and a political climate hostile to farmers.