Conservation agriculture news
Combining low-pressure, overhead sprinklers with conservation tillage may become the new ag production model for the San Joaquin Valley.
This combination of practices is quite common in many irrigated regions outside of California but are relatively new here in the Golden State. However, they may soon be much more important for California producers based on information presented at an evening field tour held on June 10 in Five Points.
This event was coordinated by the Conservation Tillage and Cropping Systems Workgroup and brought together farmers, leading conservation tillage (CT) researchers, and overhead irrigation industry representatives for the over 100 participants in attendance.
“Conservation tillage” is a type of crop management system - such as no-till and strip-till - that leaves crop residues on top of the soil when going from one crop to the next. CT is also a variety of the other “minimum tillage” approaches that reduce the overall number of tillage passes by at least 40 percent of standard tillage systems.
UC Davis researchers Karen Klonsky and Will Horwath have been evaluating the performance of CT tomato and cotton rotations at the University’s West Side Research and Extension Center in Five Points for over 10 years. Horwath, a soil scientist, reported that following eight years of CT farming, soil carbon in the top foot of soil increased by about 23 percent relative to the conventional, tillage-intensive system. That very roughly equates to a greater than 40 percent increase in organic matter.
This is a significant finding as it is the first such outcome in California coming from a long-term study. Klonsky, an ag economist at Davis, reported that tomato yields were about 9 percent higher in the CT versus standard tillage systems.
During the last five years of the study, there have been no yield differences between the tillage systems in the cotton portion of the rotation. There were some establishment problems early on in the experiment that pushed overall cotton yields to 90 percent of those of the standard tillage systems. Fuel use in CT systems was estimated to be 28 percent less than the conventionally-managed systems.
These findings are important and quite timely for San Joaquin Valley (SJV) producers but their significance may even be greater when these practices are added to center pivots or lateral move irrigation systems. With mechanized irrigation, tillage that is typically needed to create and maintain planting beds and furrows that enable surface irrigation are theoretically no longer required. This merging of CT and overhead irrigation technologies was the focus of the second half of the June 10 twilight information event.
Two overhead irrigation studies are currently underway at the West Side Research and Extension Center. One has compared a wheat/corn rotation under overhead irrigation with a conventional, surface irrigation scheme. UC Davis researcher, Jeff Mitchell, reported using 65 percent less water than furrow irrigation but resulted in similar wheat yields.
UC Davis graduate student Brooks Landers also presented information showing higher application uniformities and less deep percolation losses with the overhead system. Following a number of presentations by overhead irrigation company representatives, participants visited the farms of John Diener and Scott Schmidt.
These farmers have used overhead irrigation for about five years to irrigate wheat, corn, onions, sugar beets, alfalfa, cotton and tomatoes. These two West Side farmers got started with overhead irrigation in 2005 when they traveled to Washington State and to meet with center pivot farmers and overhead irrigation company experts.
After meeting with and learning from two Washington farmers who were managing the irrigation of upwards of 8,000 acres all by themselves using automated overhead systems, both Diener and Schmidt returned to their farms and quickly began developing their overhead irrigation management skills. They now use several 135-acre pivots on their farms.
Diener pointed out the precision application and automation aspects of overhead irrigation that allow him or his manager to run his systems using cell phone control. Schmidt pointed out the fact that overhead irrigation is different since you tend to be dealing with the top 18 or so inches of soil and thus irrigation timing and frequency must be carefully finessed.
For more information on these emerging SJV farming technologies, visit the Conservation Tillage and Cropping Systems Workgroup’s website at http://groups.ucanr.org/ucct/, or call Jeff Mitchell at (559) 303-9689. To become a member of the workgroup and receive periodic updates, e-mail Mitchell at firstname.lastname@example.org.
Discussions have been initiated toward the formation of the California Overhead Irrigation Alliance. The alliance will be a diverse group of farmers, private sector representatives, university and other agency folks interested in developing and extending information on overhead, mechanized irrigation systems here in California. The group will hold a “founders’ meeting” on Friday, Oct. 1, in Five Points.
Because of the obvious connections and possible benefits of merging or coupling overhead mechanized irrigation with conservation tillage crop production approaches, it makes good sense for the Conservation Tillage and Cropping Systems Workgroup to be involved with this emerging initiative.
"It remains to be seen what form a partnership between the workgroup and the alliance might take, but as options become clearer and more focused, I’ll try to pass on additional information on what is being considered so that we might discuss things together," said Jeff Mitchell, the Conservation Tillage and Cropping Systems Workgroup chair.
Several UC scientists are already involved in overhead mechanized irrigation research and extension efforts at the UC West Side Research and Extension Center, but if others are interested in learning more about this overall endeavor or our ongoing work in this arena, please call Mitchell at (559) 303-9689.
“I haven’t seen earthworms in these fields in years,” said Firebaugh farmer Alan Sano. Sano and his partner, Jesse Sanchez, combine subsurface drip irrigation, winter cover crops and strip tillage to consistently produce a high-yielding crop of processing tomatoes.
In addition to boosting yield, the system they developed for the 4,000-acre farm is cheaper, increases soil organic matter and improves the tilth of their silty clay soil.
The farmers took several trips to the Midwest and consulted with UC Davis Cooperative Extension specialist Jeff Mitchell to learn the improved management techniques they applied on the farm.
After switching from furrow irrigation to drip, Sano and Sanchez began experimenting with cover crops.
"It wasn’t always an easy transition into cover crops," Mitchell said. "It did take some time to learn the best way to manage them."
As the benefits of years of cover cropping accumulated, they saw that they didn’t need to till the entire field to get good soil-seed contact; they only needed to till a strip of soil a few inches wide.
Recently, they shared their innovative farming system with other growers at an open house event sponsored by California's Conservation Tillage and Cropping Systems Workgroup.
Farmers interested in adopting conservation tillage techniques may contact Mitchell for more information at email@example.com.
Leading San Joaquin Valley conservation tillage farmers Scott Schmidt of Five Points and Dino Giacomazzi of Hanford recently hosted a group of 38 no-till farmers from Western and South Australia. The visit was part of a five-week excursion the Australians were conducting through conservation agriculture regions of the US and Canada.
The Valley tour was jointly coordinated by California’s Conservation Tillage Workgroup, a diverse group of over 1,500 farmer, private sector, public agency and University members, and Crabtree Ag Consulting’s “No-till” Bill Crabtree of Beckenham, Western Australia. Crabtree, a renowned and award-winning no-till pioneer and promoter whose efforts have contributed substantially to the adoption of no-till farming on over 90 percent of the wheat acreage in Western Australia, and California CT workgroup chair Jeff Mitchell of UC Davis met in 2006 at an international conference on no-till adoption in New South Wales, Australia. Crabtree made a presentation at one of the California workgroup’s farmer meetings in 2007 in Five Points. The two no-till researchers have remained in contact since 2006 and worked together in organizing this summer’s conservation farming SJV visits.
This year’s Australian tour group made a stop in the San Joaquin Valley to learn about the progress farmers and researchers have recently made with conservation tillage cropping systems. The group was on their way from visits in Southern California to more traditional no-till regions in the Dakotas and Canada.
Their first farm visit was with Scott Schmidt, manager of Farming ‘D’ in Five Points. The diverse crop mix produced by this farm - which includes processing and fresh market tomatoes, wheat, cotton, onions, garlic, alfalfa and lettuce - contrasted sharply with the monoculture wheat fields common throughout Western and South Australia where average annual rainfall ranges from 200 to 400 mm (8 to 16 inches) and occurs primarily during the winter (similar to the SJV).
Within the diverse crop rotations that are pursued at Farming ‘D,’ Schmidt has developed a number of minimum tillage techniques and implements. He now contemplates converting segments of these rotations to even more ambitious conservation tillage management in the future. Schmidt is also a local pioneer in the use of overhead, mechanized center pivot irrigation.
The flexibility afforded by irrigating with center pivots makes the conversion to more advanced CT systems more feasible. The tillage typically required to establish beds and furrows for surface irrigation may no longer be needed under center pivot irrigation.
Following their visit with Schmidt, the Aussie no-tillers crossed the Valley and were hosted by Dino Giacomazzi and three generations of his family at their dairy in Hanford. Over the past five years, Giacomazzi has developed and refined strip-tillage corn and no-till winter wheat and triticale planting techniques. He proudly and methodically walked his visitors through his entire silage production process.
While the production contexts and details vary widely between Western and South Australia and the San Joaquin Valley, in many ways the fundamental drive toward developing conservation tillage systems that farmers in both regions exemplify are universal. Cutting production costs by reducing tillage passes results first in cheaper production and, as long as yields can be maintained or improved, more profitable production systems.
“What we do as farmers must, in the first place, be economical,” SJV CT farmer Giacomazzi pointed out. “The environmental benefits are great, but our production systems have to be first and foremost economical.”
For Giacomazzi, those environmental benefits have included fewer emissions into the air, more residue on the soil surface, and more organic matter in the soil. For the Australian no-tillers, it has meant combatting soil erosion which was causing lower yields and higher production costs. It had become nothing short of a national plague 20 ago in Western Australia’s light textured soils that are very susceptible to wind erosion.
More information on local conservation tillage is available at the CT Workgroup’s website: http://groups.ucanr.org/ucct/ and in the book by No-till Bill Crabtree, Search for Sustainability with No-till Bill in dryland agriculture.
Tomato producers interested in cutting costs, reducing inputs and improving their soil, received a strong jump start to planning their 2011 seasons by participating in a recently-held “how to get started with conservation tillage and cover crop systems” discussion held at Sano Farms in Firebaugh.
The open house event was conducted by Alan Sano and Jesse Sanchez and sponsored by California's Conservation Tillage and Cropping Systems Workgroup. Sano and Sanchez were the Workgroup's 2009 Farmer Innovator award recipients and have been refining and perfecting their conservation tillage, drip-irrigated, and cover crop-containing tomato systems for over five years with both economic advantage and resource conservation benefits. The systems that they’ve developed are cheaper, have increased soil organic matter and improved soil tilth, and have actually increased processing tomato yields at their 4000-acre farm in western Fresno County.
Sano and Sanchez started their quest for improved tomato production practices when they switched to subsurface drip irrigation as a means to improve irrigation management. Once they learned how to manage and gain advantage from their drip system, they then began introducing winter cover crops into their tomato system to add organic matter to the soil and break up their tomato monoculture. Cover crops have now actually become such a valuable and integral part of their system, that they typically dedicate the equivalent of a 3 inch pre-irrigation to get the cover crop started in the early fall of each year ahead of the following season’s tomatoes. Triticale has been the cover crop of choice to date, but this fall following the 2010 tomato harvest, they’re going to experiment with a late summer legume cover, cowpeas.
Their goal is to kill the cover crop before it grows too large with RoundUp® and then let it “melt” down before they come in with an Orthman 1-tRIPr strip-tiller just ahead of transplanting tomatoes. By managing the cover crop so as to kill it before it grows too big, they are able to gain advantages of the additional crop in terms of winter weed control and extra carbon into their soil system. They’ve increased soil organic matter by 50% since they started with this approach.
Additional information and assistance in planning and implementing these sorts of cost-saving conservation tillage approaches in the coming 2011 season is available through the Conservation Tillage and Cropping Systems Workgroup by emailing Workgroup Chair, Jeff Mitchell, at firstname.lastname@example.org, or by phoning him at (559) 303-9689.