Tulare County

Field Crop Notes (January 2000)

In This Issue

• Meeting announcements - Using Lagoon Water Nutrients for Crop Production
  
• Trial results: 1997 - 1999 Alfalfa Yield Trial
  
• 1999 Tulare County Silage Corn Trial
  

Alfalfa Variety Yield Results from 1997-1999 Trial

For those who haven't planted alfalfa yet this year, the results from the University of California variety trial at the Kearney Ag Center near Reedley are reported in Table 1. For growers who plant in fall, this information is too late to help in the selection of varieties, but due to fall harvests and analyzing yields at each variety trial location, it is impossible to report this information any sooner.

These trials are based on small plots where there is limited wheel traffic over the plots. Yields are based on a green weight and then adjusted to 100% dry matter based on moisture samples taken during harvest. Results from experimental varieties are also included in this report.

Note that some of the varieties that are in the top 10 for the average of the 3 years were not in the top 10 in the first year of the trial (which explains our policy not to issue a report after just 1 year of harvesting a trial). Also note that the top 23 varieties are in the same statistical class meaning they are followed by an "A." This means that the differences between the yields of those varieties are too small to say with confidence that the difference is truly because one variety was better than the other. The difference may be due to chance.

A common question is, "Which variety has the highest quality?" Unfortunately the UC trials do not have the resources to collect and analyze for quality at each cutting. Several years ago they did collect quality data. Although there were a few differences among varieties at some cuttings, there was no consistent trend among varieties within a dormancy class. In general, if there are inherent differences in quality among varieties, at this time these differences are rather small and cutting schedules and management of harvest operations have more impact on final quality than variety selection.

Cutting on a shorter schedule should result in lower yields but higher quality. Repeated cutting on a schedule of less than 28 days for a dormancy 8 variety will result in reduced stands due to over- withdrawal of crown and root reserves. However, plants can recover if they are allowed a longer cutting schedule somewhere in the season. For example, cut on a 28 day schedule in April, May, and June. Then cut at 26 days in July and August, followed by 28-30 days in September and October. The plant will tell you when it is ready for cutting by producing new shoots at the base of the plant (regrowth). It is extremely important to look for regrowth in the September and October cuttings because that will tell you that you have allowed the plant to recover from any shortcomings during the summer.

Raking when the windrow is too dry is the best way to ruin quality. Baling too dry has also been shown to reduce quality but not as drastically as raking a dry windrow.

Influence on alfalfa quality of the time of day when swathing occurs has been a subject gaining research interest in recent years. All plants photosynthesize when the sun is out, and all plants respire during both daylight and nighttime conditions. During the day, photosynthesis (production of sugars and nutrients) outpaces respiration (the utilization of nutrients for making bigger molecules such as cellulose for cell walls). During the night when there is no photosynthesis there is a reduction in nutrients as they are used up by respiration but are not replaced. Research to date indicates a general increase of non-structural carbohydrates (which contribute to "TDN") in alfalfa during the afternoon and a lowering of percent crude protein (percentage wise if one component such as sugars increases, then at least one other component has to decrease because percentages add up to 100%). These increases of nonstructural carbohydrates do not always translate to higher percent TDN or lower % ADF when the alfalfa is cured and baled commercially. But if you are trying every angle to increase alfalfa quality on your farm, swathing in the late afternoon or early evening is one more practice you may want to try. For further information, refer to the articles in the 1998 and 1999 Proceedings of the California Alfalfa Symposium.

Silage Corn Trial Results

The yield results of the 1999 Tulare County silage corn trial are included in Table 2. Quality analyses are not yet completed and will be reported in a later newsletter.

In general, the weather last summer was very conducive to high corn yields. There were only a few very hot days that could have caused heat damage at pollination. The optimum maximum temperature for corn is 86° F so, even though we consider corn as a sun-loving crop, it does better when day and night temperatures are below 90°.

The Tulare County trial was well managed and fertilized. It did not receive pond water from the dairy. It was sprayed for mites with Comite.

Using Lagoon Water Nutrients for Crop Production

There will be two short courses conducted by UC Cooperative Extension on using lagoon water for crop production. Each short course consists of three sessions. The first short course has less detail, less problem solving worksheets and no test at the end. It is primarily geared for growers and dairy producers using lagoon water for irrigation. The second short course will have more hands-on problem sets and will end with a test. Growers, dairy producers or consultants can attend either short course. Certificates will be given to those attending all three sessions for either short course.

Manure Composition and Management
Agricultural Building, 2500 W. Burrel, Visalia
Monday, January 31, 2000
1 - 3:30 pm


Update on nutrient management regulations; dry manure composition and management; lagoon water sampling and lab analysis; when and where to sample lagoon water; managing salts in lagoon water; establishing a whole farm nutrient budget.

How to Measure and Adjust Lagoon Water Applications
Agricultural Building, 2500 W. Burrel, Visalia
Monday, February 7, 2000
1-3:30 pm


Measuring nitrogen concentration with quick tests; methods of measuring lagoon water application; adjusting lagoon water application rates; record keeping.

Balancing Nutrient Applications with Crop Uptake
Agricultural Building, 2500 W. Burrel, Visalia
Monday, February 14, 2000
1 - 3:30 pm


Applying lagoon water through irrigation systems; seasonal patterns of crop nutrient uptake; using soil and plant tissue tests. Are pathogens an issue?

Participants are strongly encouraged to bring a sample of undiluted lagoon water to the first class. A sample taken during an irrigation is preferable to a sample taken at the flush unless both share the same outlet. Samples may be submitted anonymously, with results reported by code number only. Keep samples refrigerated during storage and on ice during transport.

Short course #2
(Same topics but more detailed, exam at end; $12.00 fee/session to cover lunch.
Preregistration is required. Call (559) 733-6363 by January 24, 2000.)

Manure Management and Composition
AgTac Center, 4175 S. Laspina, Tulare
Wednesday, February 2, 2000
9:30 am to 2 pm

How to Measure and Adjust Lagoon Water Applications
AgTac Center, 4175 S. Laspina, Tulare
Tuesday, February 15, 2000
9:30 am to 2 pm

Balancing Nutrient Applications with Crop Uptake
AgTac Center, 4175 S. Laspina, Tulare
Tuesday, February 29, 2000
9:30 am - 2 pm

Additional Workshops

Monitoring Wells on Dairies - Producers only

Agricultural Building, 2500 W. Burrel, Visalia
Monday, February 28, 2000
1 - 3:30 pm

Siting and construction of monitoring wells on dairies; legal considerations; results of the Northern San Joaquin Valley monitoring well survey.

You must own or operate a dairy to attend this Monitoring Well Workshop. A similar session for crop consultants and others will be conducted on March 1, 2000.

Agricultural Building
2500 W. Burrel, Visalia
Wednesday, March 1, 2000
1:00 - 3:30 pm

Agricultural Building
2500 W. Burrel, Visalia
Thursday, March 2, 2000
9:30 am - noon

Space is limited. Call and pre-register.

Agricultural Building
2500 W. Burrel, Visalia
Thursday, March 16, 2000
9:30 am - noon

Space is limited. Call and pre-register

Agricultural Building
2500 W. Burrel, Visalia
Thursday, March 23, 2000
9:30 am - noon



Space is limited. Call and pre-register.

For more information contact Carol Frate, UCCE Tulare County, (559) 733-6363.