Strip tillage changes the game for Sano Farm

Alan Sano, co-owner of Sano Farm in Firebaugh, on the west side of California’s parched San Joaquin Valley, and Jesse Sanchez, the farm manager, are onto something.

“We got into strip tillage (ST) about eight years ago,” Sano says. “Our yield is higher than when we used conventional tillage, and we’ve eliminated five or six passes with tractor work and labor. Every year is getting better.”

Before transplanting tomatoes in the spring, Sano Farm uses row units from an Orthman model 1-tRIPr to work the soil in the beds to a depth of about 6 inches. It loosens the soil, mixes in the residues from the cover crop, applies starter fertilizer and leaves a firmed zone of soil where the transplants will be placed.

With ST, only about 20 percent of the farm’s 66-inch-wide tomato beds need to be tilled, says Jeff Mitchell, CE cropping systems specialist at the University of California Kearney Agricultural Center in Parlier. Cover crops and drip irrigation help keep weeds down.

Switching from conventional tillage involved start-up costs for specialized equipment and GPS. GPS saves time because the equipment makes fewer overlaps or skips, and it also keeps the equipment away from the buried drip tape in the crop growth zones.

Because the equipment makes fewer passes, Sano saves on the cost of maintenance, repairs, fuel and labor. The economic benefits are usually minor, though, says Mitchell, because tillage costs tend to be a fairly small part of the total budget. Still, there are a number of other advantages. ST improves the quality of the air on a farm because it reduces diesel fuel emissions. Because the cover crops add organic matter, they improve the quality of the soil and water infiltration and decrease soil erosion from both wind and water.

Sano, his parents, two sisters and brother co-own the 4,000-acre farm. He started farming in 1980 and has been running the 2,300-acre tomato growing operation from a wheelchair since 1981, when an accident paralyzed him from the ribs down. He employs approximately 25 to 35 people, depending on the time of year.

He and Sanchez received the 2009 Conservation Tillage Farmer Innovator Award from California’s Conservation Tillage and Cropping Systems Workgroup, of which Mitchell is the chairman. The award gives greater visibility to leaders in conservation tillage.

Comparison of Standard Tillage and Conservation Tillage

In 2009, Jeff Mitchell of the department of plant sciences at the University of California, Davis; Karen Klonsky, also of UC Davis; and Gene Miyao of UC’s Cooperative Extension in Woodland wrote up the results of the first five years (1999 to 2004) of their 10-year study at the UC West Side Research and Extension Center in the San Joaquin Valley, Calif. It compared the results of standard tillage (ST) and conservation tillage (CT) of tomato and cotton crops both with and without winter cover crops under furrow irrigation.

They used the customary ST system in the area. Tomato beds were disked and reformed following the cotton harvest, and then shaped before the tomatoes were transplanted. The cover crop, triticale/rye/vetch, was disked in each spring.

The CT system disturbed about half as much soil as the ST system. Cotton was no-till seeded except for a one-pass shallow-root undercutting following the harvest for pink bollworm management compliance. Tomato beds were readied with furrow sweeps, but also were no-till transplanted. The cover crop, also triticale/rye/vetch, was sprayed with glyphosate, chopped and left on the soil surface as a mulch.

Winter triticale cover crop at Sano Farm. The ideal crop is inexpensive, gives quick cover and has a high amount of root biomass to control weeds, needs minimal irrigation and is easily killed with herbicide.

In the CT system with a cover crop:

<0x2022> The tomato plants often grew more slowly early in the season when the cover crop mulch was heavy. This may be due to lower above and below-mulch temperatures.

<0x2022> The largest challenge was managing weeds. They generally cultivated two to three times per season and hand-weeded. Because herbicides weren’t incorporated into the soil, many late-season weeds grew in the furrows.

<0x2022> More surface “trash” entered the harvester. However, virtually all of it typically was removed by the harvester before it entered transport trailers.

Throughout the study, yields with CT with no cover crop matched or exceeded ST both with and without cover crops. CT yields with cover crops have been more problematic. They were usually lower than all the other systems, although in some years they did catch up. This may be due to lower soil and aboveground temperatures, more weed competition and possibly nitrogen immobilization.

Results indicated that planting and harvesting tomatoes is possible with CT. Yields comparable to those attained without a cover crop, the standard winter fallow technique, may be achieved with certain reduced-till approaches that do not result in excessive cover crop regrowth or weed competition with the tomato crop.

Additional information about conservation tillage in California is available at the website of the Conservation Cropping Systems and Irrigation Institute:

The first component of the system is the subsurface drip irrigation system, which they installed about eight years ago because of water issues, Sano says. Because the subsurface drip applies water precisely to plant roots and keeps the soil surface dry, fewer weeds grow, which is a big advantage with ST.

Once the drip was in, Sanchez suggested experimenting with ST. They began with 450 acres. The next year they expanded it to all 2,300 acres of tomatoes.

Before they transplant the tomatoes, usually around March 20, they use row units from an Orthman model 1-tRIPr to work the soil in the beds to a depth of about 6 inches. It loosens the soil, mixes in residues from the cover crop, applies starter fertilizer and leaves a firmed zone of soil where the transplants will be placed.

The ground may be colder at the usual planting time because of the cover crop, Mitchell says. “Growers have to recognize that below and above the soil the air can be 4 degrees lower. That can be a potential risk.”

At Sano Farm, they transplant tomatoes with a conventional five-row Checchi dual-row transplanter. It drills a double row in the transplant line about 12 inches wide in the center of 66-inch-wide beds. They apply additional fertilizer with the drip irrigation during the growing season.

They harvest between late July and early September with a harvester that picks the vines up, shakes the fruit off and puts the vines back on the bed, Sano says.

“When they’re green, it’s easy, but when they’re semidry, they interfere with the tillage. We use a flail mower to shred the vines so when they’re on the bed they’re in small pieces and can get incorporated into the ground.”

The second component of the system is tillage. The first pass takes place after the harvest, with an In-Furrow Chisel by Wilcox Agri-Products that tills the soil deeply and breaks up compacted soil in the beds and the furrows. They use the Wilcox Heavy Duty Performer for the second pass to incorporate the residues into the soil, aerate the soil and shape the beds for the next season.

Jeff Mitchell, CE cropping systems specialists in the field at the University of California Kearney Agricultural Center with an herbicide-killed cover crop.

The third component is the cover crop, which they typically sow in late October or early November, Sano says. They use a modified 25-foot Great Plains drill that seeds across the top of the beds but not in the furrows.

Growers use mulch in some areas of the country, but it’s expensive, Mitchell says. The ideal cover crop is inexpensive, gives quick cover and has a high amount of root biomass to control weeds, needs minimal irrigation and is easily killed with herbicide. Sano and Sanchez have experimented with different crops, including triticale, barley and wheat. They also planted garbanzos last winter, which fix nitrogen in the soil. Once they’ve killed the cover crop, they leave it in place on top of the beds as mulch.

“What we try to do is spray [herbicide] in late December or early January,” Sano says. “Then the rain in January and February incorporates the cover crop into the ground.” One year was too rainy, though, and they had to delay spraying. The cover crop grew so tough that the residue slowed down the harvester. “We weren’t able to get in on time and spray the cover crop when it was green,” he says. “We had to shred it with the flail mower. There were still roots there during the harvest. It made a mess.”

You have to optimize all the pieces here, Mitchell says. “If you aren’t careful, you may run into problems managing the cover crop. You have to make sure it really has died. And if there’s too much residue in the transplant line, you may have skips or spares when you’re transplanting.”

The 66-inch tomato beds after the cover crop was sprayed with herbicide. The rain in January-February incorporates it into the ground.

He says you have to be on top of the nitrogen fertilizer because the plants may grow more slowly at first. Irrigation management is another area to pay close attention to. He notes that the plants might need to be irrigated earlier than with conventional tillage or more frequently, but they probably won’t need more water altogether.

In fact, he says, “Our research shows the ability of mulches to reduce the surface water evaporation. There may be some savings you can garner from not tilling up the surface in the spring and from having mulch.”

ST is still a work in progress, Mitchell adds. “They’re [Sano and Sanchez] trying to identify better crops, figure out the best postharvest tillage, how to manage weeds and avoid disease. But what these two gentlemen did over eight or nine years now literally refined and troubleshot the whole system and developed what is a state-of-the-art tomato production system.”

The author is a freelance writer based in Altadena, Calif.