- Author: Michelle Leinfelder-Miles
On May 20th, we planted a grain sorghum seeding rate trial in the Delta to determine an optimum seeding rate for the unique Delta growing environment. Sorghum is a relatively new crop in the northern San Joaquin Valley and Delta region. The most recent crop reports available from the San Joaquin and Sacramento County Agricultural Commissioners' offices (2014) do not specifically name sorghum in their lists of field crops, indicating that it has not been widely planted. Anecdotally, however, I have heard that acreage is up this year as growers diversify their crop portfolios during this time of low commodity prices.
UC research on sorghum has increased over the last few years, primarily in the southern San Joaquin Valley, under the direction of Jeff Dahlberg, Director of the Kearney Research and Extension Center, and Bob Hutmacher, Director of the West Side Research and Extension Center. They have been investigating grain and silage sorghum for its adaptability under drought and low-input conditions.
Sorghum grows well in environments where corn is grown, and it has similar growth habits as corn. A grower would prepare seedbeds similarly for both crops; the vegetative appearance is similar, as is fertility management. There are, however, some differences in growth and environmental requirements between the two crops. Sorghum should not be planted in cold soils, and typically growers should wait to plant sorghum until the soil temperature is at least 60⁰F. Anecdotally, growers in this area are finishing up corn planting and then moving on to planting sorghum to allow the soils to warm. Unlike corn, sorghum tillers, and the head is a panicle of grain that is self-pollinated. The panicles develop over a period of several days, and thus, short periods of hot weather are less likely to damage sorghum pollination as it may with corn.
In our trial, we planted Eureka Seeds variety 3292, which is a white sorghum variety being grown for grain. We planted on 30-inch row spacing and about 2 inches deep. The variety label specifies 16,000 seeds per pound with 85 percent germination. The grower's practice will be to plant 12 pounds of seed per acre, based on seed representative and neighboring grower recommendations. Our trial is a randomized complete blocks design with four replicated blocks of five treatments: 5, 6, 9, 12, and 15 pounds per acre. These treatments correspond to approximate plant populations of 68,000, 81,600, 122,400, 163,200, and 204,000 plants per acre, respectively. (This takes into account the 85 percent germination.) Over the course of the season, we will evaluate the trial for stand establishment, weed pressure, and yield in an effort to determine optimum seeding rate.
- Author: Michelle Leinfelder-Miles
The 2016 UCCE grain corn variety trial was planted on April 27th. The trial is located in the Delta on Tyler Island. Three replicate blocks of eighteen varieties were planted by air planter. The eighteen varieties included 16 varieties submitted by seed companies and two varieties submitted by the grower, which are presented in Table 1. Each replicate consists of four 30-inch beds on an average row length of about 1200 feet. Seed was planted two inches deep and six inches apart down the row, for an approximate planting density of 35,000 seeds per acre. The soil is a Rindge mucky silt loam with approximately 20 percent organic matter in the top 15 inches of soil. Approximately 55,600 acres in the Delta are described by the Rindge classification. Over the course of the season, we will evaluate the following parameters: stand count, days to bloom, fusarium ear rot, head smut, common smut, lodging, ear height, yield, and grain moisture at yield. Don't hesitate to contact me if you have any questions about the trial, and stay tuned to this blog for trial results at the end of the season.
Table 1. Field corn varieties planted in the 2016 UCCE field corn variety trial.
Brand Initials |
Variety Number |
Brand Name |
Submitted by |
CP |
6525VT3P/RIB |
Croplan |
Stanislaus Farm Supply |
CP |
7087VT2P/RIB |
Croplan |
Stanislaus Farm Supply |
DKC |
62-08RIB |
DeKalb |
Monsanto/Ag Seeds |
DKC |
63-07 |
DeKalb |
Grower |
DKC |
63-71 |
DeKalb |
Monsanto |
ES |
7514VT2P |
Eureka Seeds |
AgReliant Genetics |
ES |
7667VT2P |
Eureka Seeds |
AgReliant Genetics |
G |
6708VT2P |
Golden Acres |
AgReliant Genetics |
G |
7601VT2P |
Golden Acres |
AgReliant Genetics |
INT |
6612GSS |
Integra |
Wilbur Ellis |
INT |
6474DGVT2PRORIB |
Integra |
Wilbur Ellis |
LG |
5701VT2P |
LG Seeds |
AgReliant Genetics |
LG |
5622VT2P |
LG Seeds |
AgReliant Genetics |
P |
31N27 |
Pioneer |
Grower |
SX |
5543RR |
Baglietto Seeds |
Baglietto Seeds |
TGY |
8156GT |
Tech Ag |
Lyman Ag Group |
- Author: Michelle Leinfelder-Miles
Wireworms are the soil-dwelling larvae of click beetles. They feed on the seeds and roots of various crops and are a particular pest of field corn in the Sacramento-San Joaquin River Delta region (Figure 1).
Two trials were conducted in 2015 – one on Staten Island and one on Tyler Island. The soil type at both trial sites is a Rindge muck, which characterizes approximately 57,000 acres in the Delta. The Rindge muck is high in organic matter and considered very poorly drained, and thus, it was a good soil for these trials because the soil stays cool and damp into late spring and early summer. Both sites have heavy wireworm pressure, according to the growers, and were planted with corn the previous year. The Staten Island trial was planted on April 15, 2015, and the Tyler Island trial was planted on June 9, 2015, both having four replicate blocks.
We evaluated growth parameters starting at about a week after planting for a period of about six weeks. Growth parameters of interest were emergence, stand count, vigor, damaged plants, dead plants, and height. Additionally, on the second week of evaluations, ten seedlings were lifted. Dead and live wireworms were counted on the seeds, roots, and surrounding soil, and the seedlings were given a visual health rating. The trials were harvested on September 30th and October 14th (Staten and Tyler Islands, respectively). Harvest parameters included a plant count, yield, grain moisture, and bushel weight. Additionally, at the Staten Island trial, Johnson grass plants were also counted because weed pressure was high.
Growth results are described in the online report. Yields at the Staten Island trial were highly variable, and both wireworm and weed pressure may have contributed to the variability (Table 1). Johnson grass pressure was especially high in treatments where plant stands were compromised by wireworms or birds. High weed pressure can be a consequence of poor wireworm control because stands that are compromised do not provide the consistent shading to out-compete weeds. Yields can suffer as a result. The Lumivia™ + Cruiser® treatment yielded the highest, and Lumivia™ 750 yielded the worst, even lower than the untreated control. The poor result of Lumivia™ 750 may be explained by uncontrollable factors, namely, bird damage and high wireworm pressure. The polymer treatments that were tested at the Tyler Island site showed no yield benefits over the non-polymer treatments and yielded similarly to the commercial standard, Poncho® Votivo® (Table 2).
The trial results illustrate that growers have several options for managing wireworms. Across both trial locations, results suggest that Lumivia™ 250 + Cruiser® 250, Lumivia™ (500 or 750) in combination with bifenthrin 125, and commercial standards Poncho®, Poncho® Votivo®, and Cruiser® provide good control against wireworm in the weeks after planting when corn is in the seedling stages. While we saw few statistical yield differences, the control and resulting better stands have the potential to improve yields over non-treated seeds. The two Poncho® products are commercially available from Bayer CropScience, and Cruiser® is commercially available from Syngenta. Lumivia™, a Dupont product, is not yet commercially available as a corn seed treatment in California, but if it were to become so, it would provide growers with an alternative to the neonicotinoid treatments. When making decisions on products, growers should consider their wireworm pest pressure and other soil-dwelling pests that could limit their production. Growers should also consider which seed treatments they have been using and whether those are still controlling pests. If not, rotating to a different chemistry might be a way to bring pests back under control. Integrated pest management practices recommend rotating chemistries for insect resistance management.
- Author: Michelle Leinfelder-Miles
I was speaking with a colleague a few weeks ago about field drainage in the Delta. Our conversation reminded me of a farm visit that I made a couple of years ago. I visited a corn field that was not growing well, and sections of the field had standing water. I consulted with UC Water Management Specialist Emeritus, Terry Prichard, on what this grower could do to improve drainage. I wondered about installing drainage tiles. The irrigation specialist did not recommend installing drainage tiles in the Delta. The high organic matter soils are so fine that the perforations in the tile just plug up. He also did not recommend a deep plow because some Delta soils have a layer of “blue clay.” It is not actually clay but it is anaerobic soil (which is what makes it blue) that has never been near the surface. The irrigation specialist had once visited a field that had been deep plowed and brought up blue clay. The field became completely unmanageable.
What the irrigation specialist did recommend was to dig 4-foot (deep) drain ditches. These would run parallel to the furrows and should be about 500 feet apart. These ditches would connect to another ditch that runs to the main drain of the island. These dimensions are not a prescription for all Delta sites, but they could give landowners a general guide for managing drainage, and in the case of the corn field I visited, make wet fields farmable. Each 4-foot ditch will result in about 10 feet of “wasted” (non-farmed) space, but having these ditches (and keeping them clean) is the only way to get the water out of the soil profile and off the field.
Before any effort is put into digging ditches, it would probably be beneficial, particularly for new landowners, to see from an internet mapping interface if there are any lines in their fields that would indicate past ditches or different soil types. If previous landowners leveled the land, they may have filled in drainage ditches.
- Author: Michelle Leinfelder-Miles
Greetings! I started this blog as a component of my Extension program for field crops growers and allied industry in San Joaquin County and the greater Sacramento-San Joaquin Delta region. As a UC Cooperative Extension farm advisor, an important part of my outreach is to make farm visits when growers or consultants have observed something unusual or alarming in the field. Additionally, I answer questions over the phone or by email. All of these experiences may provide learning opportunities for a broader audience, so I will use this blog to document and archive this outreach. I will make certain to keep the identity of the parties involved private.
As is customary with blogs, please provide your feedback! I welcome comments on similar observations or follow-up questions; however, this is not a venue for advertising, so comments will be moderated. This blog provides an opportunity for us to learn from each other.