In This Issue

Silage Corn Variety Trial Results

The 1998 Tulare County silage corn variety trial was conducted with the cooperation of Steve Milanesio. Bed spacing was 38 inches and each plot was 8 rows by ½ mile. Corn seed companies were invited to submit one variety. There were 17 varieties (listed in Tables 1 and 2) and 4 replications. Both Madera loam and Lewis fine sandy loam soils were in the field.

Total nitrogen applied included a preplant application of 77 lbs N/acre as ammonium sulfate. A sidedress application on July 12 of NH3 at 175 lbs N/acre and 38 lbs N/A water run on August 24 with UAN32 adds up to 290 lbs N/acre. In addition, lagoon water was included in some irrigations.

Due to "El Niño" planting was delayed until June 23. A vacuum planter was used and, although average stands differed among varieties, for any specific variety stands were uniform. Some cutworms were observed shortly after emergence and Asana XL was applied on July 1 in a 10 inch band to prevent significant damage. Average plant populations taken on July 7 ranged from a low of 27,857 to a high of 31,420 plants per acre (Table 1).

Prowl was applied at layby for weed control. Spider mites were not a problem but one pass with Comite was made around the field. No damage due to Comite was observed in any variety.

Tassels began to emerge by August 10 in the earliest varieties when growing degree units were around 1200. The earliest varieties to tassel were Exogen 404, Cal Valley 3171, Asgrow RX 813, Pioneer 32K61, and Cargill 9027. The least mature variety, NC+ 7665, had not tasseled at all by August 14.

By September, leafminer damage was obvious on lower leaves in all varieties and in some cases higher leaves (6th and 7th leaves from the bottom). A subjective rating at the end of the season evaluated the health of the lower leaves based on leaf miner damage and senescence. Gutwein 2696, Farm Valley 4656WX, and Pioneer 32K61 had the best ratings for green lower leaves and reduced leafminer damage.

Lodging, which was more widespread in corn than usual throughout the county in 1998, was evident by September 11th and at harvest time was scattered throughout the trial. Some squirrely winds associated with unstable weather contributed to lodging but may not be the only reason. In some plots, plants appeared to fall in a 360o pattern. Due to the large size of the trial, an aerial photo was taken in order to determine the percent lodging in each plot. However, the resolution was not clear enough to identify plots with certainty. All varieties had some lodging.

Plant and ear heights, listed in Table 1, were measured just before harvest. Exogen was the shortest variety and was noteworthy as looking spindly and unimpressive.

Harvest began on September 29 and continued until October 2, 1998. Silage trucks were weighed on the scale at the dairy. Samples for moisture and quality were taken from each truckload as it dumped at the silage pile. The equipment and drivers from Netto Ag were very good at picking up lodged areas with the exception of 4 plots in the second replication where lodging was particularly bad and the machinery plugged. Yield data was analyzed with these plots calculated as missing.

Yields, listed in Table 2, are given both "as harvested" and "adjusted to 70% moisture." Moisture levels at harvest ranged from a low of 67.4 % to a high of 74.9%. Comparing weights without considering the difference in water content can give an incorrect picture of results. To compensate for differences in moisture at harvest, a mathematical calculation can be done to adjust all yields to 70% moisture. While this makes it easier to compare varieties, this method also has limitations. It will tend to favor varieties that are drier than 70% at harvest and hurt varieties that are more than 70% moisture. The more a moisture content differs from 70% at harvest, the more the mathematical adjustment will be incorrect. In addition to the average adjusted weight for each variety, adjusted weights are also given for each replication in Table 2.

Variety trials such as this show the potential of varieties under the environment, soil, irrigation, and management for that location in that year. In different locations, results will often differ. The Kings County silage corn variety trial, which included some of the same varieties, was on a different soil type and the relative performance of some of the varieties was different. Yield data from that trial is summarized in Table 3. If growers are interested in trying a new variety, strip or small plantings under their own management conditions are recommended.

Trials such as this corn variety trial could not be conducted without the cooperation of the grower and the custom harvester. They are critical components to making this information available to you. If you have a chance, thank them.

Over 600 Attended 1998 Alfalfa Symposium in Reno

The California Alfalfa Symposium, held in Reno last December, was the best attended in more than 20 years. A 230-page proceedings has been published which contains valuable information about exports, harvesting equipment, soil fertility, and forage quality among other subjects. I have 5 copies that can be purchased ($10.00) at the Cooperative Extension office in Visalia or a copy may be ordered by sending a check for $10.00 (payable to U.C. Regents) to Dan Putnam, Department of Agronomy and Range Science, One Shields Avenue, University of California, Davis, CA 95616.

Table 1. Plant height, ear height, and quality data from 1998 Tulare County silage corn trial.

Table 2. Moisture percent and yield data from 1998 Tulare County Silage Corn Trial.

New Alfalfa Organization

The California Alfalfa and Forage Association (CAFA) is a newly formed group of growers and allied industry representatives. Its goals are education of the public about the importance and role of alfalfa and forages in California, leadership for the industry as a whole and service as a communication link for the alfalfa and forage industries, support for alfalfa and forage research on issues of vital importance to growers of forage crops, and providing a range of services to the hay and forage industries. A newsletter is included with membership.

The organization has already obtained a $5000 grant from the California Department of Pesticide Regulation to evaluate pest management options for alfalfa, including pesticides used and alternative practices to spraying. These evaluations have been done by several other commodity groups (such as cotton, sugarbeets, and walnuts) and are the first step to acquiring more funding to search for solutions to pest problems when registrations of currently used pesticides are threatened.

If you would like more information about the California Alfalfa & Forage Association to determine if it is an organization worthwhile to your farming operation, the address is P.O. Box 162, Davis CA 95617-0162. For those on the Internet, the Web page for the organization is: www.CalHay.org .

Nutsedge Control in Alfalfa

Yellow and purple nutsedge are troublesome weeds in many crops. Both Eptam and Zorial herbicides will suppress these weeds in alfalfa but diligence is necessary to bring populations down. A trial was conducted last year in an alfalfa field with purple nutsedge belonging to Tom Barcellos. Either Zorial Rapid 80 at 2 lbs/acre or Eptam 20G at 15 lbs/acre were applied by Gillespie Ag Service to plots 52 ft x 350 ft on March 22. The trial also included an untreated check and another treatment evaluating a different Zorial formulation which is not yet available in California and therefore not included in the rest of this discussion. There were 4 replications. This application occurred just after the first cutting. Eptam plots were irrigated the following day and over 2 inches of rain occurred between March 24 -28.

A second Eptam 20G application was made in early June but, due to miscommunication on my part, the plots were not irrigated for 4 days, making the application ineffective as Eptam granules should be incorporated within 24 hours of application.

On April 30th, the first evaluation was made. The number of nutsedge plants in a 2 sq/ ft. area was counted in 12 sites per/plot. Another evaluation was made on June 9 in the same manner. On July 6, the number of sites was doubled to 24 but the area/site was reduced to 1 sq.ft. Between August 6 and August 14, the last ratings were conducted. At that time, the evaluation method used was determining if nutsedge was present or not in 105 locations within each plot. Counts are presented in Table 4.

Results. Both Eptam and Zorial treatments had significantly fewer nutsedge plants than the untreated check in the rating on April 30. On June 9, only the Zorial plots had fewer nutsedge plots than the check which is not surprising as Eptam would need repeat applications to maintain suppression. Zorial plots still had fewer nutsedge plants than the untreated control plots on July 6th. By early August, Zorial plots still had significantly less nutsedge than the control plots but 46% of the sites evaluated had nutsedge. While this percentage was less than the 70% positive sites in untreated plots, this level of reduction is more accurately called suppression rather than "control."

Notes: Zorial 5G applied at 32 lbs product/acre. Zorial Rapid 80 applied at 2 lbs product/acre in a spray volume of 10 gpa by Gillespie Ag Service. Eptam 20-G applied by Gillespie Ag Service at 15 lbs product/acre with 40 lbs/acre of potassium as carrier. An irrigation was applied the following day. A second Eptam application in early June was not followed by rain or irrigation for 4 days so essentially was ineffective.

Want to See Berseem Clover?

Many growers have read about research in the northern part of the San Joaquin Valley evaluating interplanting or overseeding alfalfa with Berseem clover. Berseem clover is a legume which has quality characteristics similar to alfalfa. It is an annual that is planted in fall. In the Davis/Stockton area it begins growing in winter/spring before the alfalfa and can contribute significantly to higher yields in the first cutting without sacrificing much on quality. Another plus is that the Egyptian alfalfa weevil does not feed on it. Depending on the weather and variety, Berseem may grow back and continue contributing to yields for the second and possibly the third cutting.

A Berseem clover trial has been planted at the West Side Field Station to determine what varieties do best under southern San Joaquin Valley conditions. A field meeting will be held Tuesday, May 4, 1999, from 10 am to noon to see Berseem and discuss whether it fits in alfalfa production in this part of the state. Tips on managing summer alfalfa pests will also be discussed. Mark your calendars now. More details will be available later.