The annual Alfalfa and Forage Field Day at the UC Kearney Agricultural Research and Extension Center (9240 S. Riverbend Ave., Parlier, CA 93648) will take place on Wednesday, September 20, 2017. Registration begins at 7:30am, and lunch is offered at the end of event. The event is free, and no registration is required.
7:30 AM Registration
8:00 Tram leaves for field tour
- Alfalfa Varieties for Pest and Disease Management – Shannon Mueller, Agronomy Advisor and County Director, UCCE Fresno
- Remote Sensing in Sorghum to Phenotype Drought Stress – Jeffery Dahlberg, Director, Kearney Agriculture Research & Extension Center
- Sub-Surface Drip Irrigation Alfalfa Management – Daniel Putnam, CE Agronomy & Forage Specialist, UC Davis
9:15 Tram Returns
9:20 Managing Weeds in Agronomic Crop Rotations – Kurt Hembree, Weed Management Advisor, UCCE Fresno
9:40 Alfalfa Weevil Management – Rachael Long, Agronomy & Pest Management Advisor, UCCE Sacramento, Solano, & Yolo Counties
10:00 Managing Sugarcane Aphid in Forage Sorghum – Nicholas Clark, Agronomic Cropping Systems & Nutrient Management Advisor, UCCE Kings, Tulare, & Fresno Counties
10:20 Irrigation & Nitrogen Fertility Management in Forage Sorghum & Corn – Robert Hutmacher,CE Specialist, UC Davis, & Director of West Side Research & ExtensionCenter
11:00 Irrigation Systems and Salinity Management in Forage Production– Daniel Munk, Agronomy & Irrigation Advisor, UCCE Fresno
11:20 Low Lignin Alfalfa & GMO vs. Conventional Varieties for Export – Dan Putnam, UC Davis
11:40 Optimizing Surface Irrigation in High Flow Systems – Marsha Campbell-Matthews, Agronomy Advisor Emeritus, UCCE Stanislaus
12:00 PM Lunch
Continuing Education Requested: DPR 1.5 hours of Other
For more information, contact Nicholas Clark at (559) 852-2788 or firstname.lastname@example.org.
Common purslane is a summer, annual weed that thrives under warm, moist soil conditions. It has succulent stems and leaves, grows prostrate, and is a prolific seeder. Under the right conditions, fleshy stems that break away can re-root and increase infestation. Common purslane is edible and does not present any toxicity problems for livestock. There are cultural, biological, and chemical approaches to controlling common purslane. In agricultural systems, cultivation will help manage this weed when the plants are in the seedling stage, and both pre-emergence and post-emergence herbicides are effective. More information on the biology and management of common purslane is available from UC IPM.
The moisture content of common purslane stems and leaves presents a problem when it is raked into alfalfa hay and baled. With moisture in the stems, the stems are still respiring. The process of respiration produces heat. If the heat cannot dissipate, there is the potential for the hay to catch fire. Dan Putnam, UC Alfalfa and Forage Specialist, describes this in a blog post. He explains how it is critical to monitor the hay curing process and stem moisture, and he provides some guidelines for bale moisture content. This situation with common purslane is a variation on the same theme. Moisture within the bales from the purslane presents the potential for trapped heat, so it is important to control this weed, monitor bale moisture, and stack bales so that heat can dissipate.
Glyphosate tolerance, or Roundup Ready technology, is available in alfalfa. Weed control in Roundup Ready alfalfa has been reported by UC Cooperative Extension weed scientists. In stand establishment studies, Roundup controlled common purslane in the seedling stage, but efficacy was reduced on mature plants. Additionally, there is the potential for this broad-spectrum herbicide to have reduced efficacy when used repeatedly. Under conditions of repeated use, a shift in weed species populations may occur to favor weeds like common purslane.
So now, let's go back to the present situation and this PCA's consideration to control common purslane with Shark. Shark is a PPO inhibitor, also classified as a contact herbicide. These herbicides will burn leaves and stems and are most effective on broadleaf weeds. Shark was approved for use in California alfalfa in 2014 and can be used in the winter when the alfalfa is dormant or in-season between cuttings. It can also be tank-mixed with other products, like glyphosate. (Note: always consult the label before making applications.) Another herbicide of the same chemistry class, Sharpen (saflufenacil), was approved in 2016 but only for winter-dormant alfalfa. Growers should be aware, however, that contact herbicides will burn alfalfa, and the best weed control will occur on smaller weeds and with thorough coverage of the herbicide. Alfalfa regrowth could potentially be reduced in the next cutting by the equivalent of 1-2 weeks of growth, but the crop should resume regular growth, and yield should recover. See this presentation for information on weed control in established alfalfa fields.
The annual UC Davis Small Grains and Alfalfa Field Day will take place on Thursday, May 11, 2017 at the Agronomy Field Headquarters (2400 Hutchison Drive, Davis, CA 95616). Registration opens at 7:45am, and lunch is provided between the small grains morning program and alfalfa afternoon program. The event is free and open to the public, and continuing education credits will be available. Directions are as follows:
The field day is located on Hutchison Drive, just west of Davis. Take the Hwy. 113 exit north from I-80, or Hwy. 113 south from Woodland. Exit west on Hutchison Drive. Take a right at the first roundabout, a left at the second roundabout, and the Agronomy Headquarters is about ¼ mile down in a clump of trees and buildings on the left.
7:45 Registration (no charge)
Small Grains Program
8:15 Welcome and Introductions—Mark Lundy, CE Grain Cropping Systems Specialist
8:20 Overview of wheat breeding—Jorge Dubcovsky, UC Davis wheat breeder
8:25 California Wheat Commission remarks—Claudia Carter, Executive Director
8:30 California Crop Improvement Association remarks—John Palmer, Executive Director
8:35 Depart for field
9:00 – 11:30 Small grain variety evaluations, breeding, and management research
9:00 Common Wheat, Durum and Triticale variety evaluations: productivityanddiseaseresistance—Mark Lundy and Nicholas George, UCCE/UCDavis
9:30 Barley breeding update—Alicia del Blanco, UC Davis
9:45 Wheat breeding update—Oswaldo Chicaiza, UC Davis
10:00 Common wheat lines with increased resistant starch, positive and negative effects on agronomic traits— André Schönhofen, UC Davis
10:15 Triticale breeding for breadmaking quality—Josh Hegarty, UC Davis
10:30 Root differences favoring flooding and drought tolerance—Tyson Howell, UC Davis
10:45 Research progress in grain yield components—Alejandra Alvarez/Junli Zhang, UC Davis
11:00 Barley & Common Collaborative variety evaluations: productivity and disease resistance— Mark Lundy and Nicholas George, UCCE/UC Davis
11:10 Malting barley market prospects—Konrad Mathesius, UCCE Sacramento Valley Agronomy Advisor
11:15 Research update: Nitrogen management for productive & high quality malting barley—Taylor Nelsen, UC Davis
11:25 Seeding rates in grain sorghum—Michelle Leinfelder-Miles, UCCE Delta Farm Advisor
11:35 Return for lunch
12:00 Barbeque Lunch
Alfalfa and Forage Program
12:30 Welcome and Introductions—Dan Putnam, UCCE/UCD Alfalfa Specialist
12:35 Appreciation for the Field Station Staff—Brad Hanson & Ted Dejong, UCCE/UC Davis
12:45 Key Activities for California Alfalfa & Forage Association—Jane Townsend, CAFA, Sacramento, CA
1:05 Near-loss of Chlorpyrifos (Lorsban) – The story isn't over yet: pay attention to stewardship in alfalfa IPM! – Pete Goodell, UC IPM Program, Kearney Ag Center, Parlier, CA
1:20 Implementing IPM in Alfalfa Production for insects, weeds and diseases –Rachael Long & Larry Godfrey, UCCE Yolo-Solano-Sacramento Counties, Woodland, CA
1:35 Alfalfa Blogs- Electronic Communications on Pest Management of Interest to you!— Michelle Leinfelder-Miles, UCCE, Delta Region, CA
1:40 Developing cropping systems to maximize protein from alfalfa for human consumption – Dan Putnam, UC Davis, Davis, CA
2:05 Identifying the Bad Guys—Identifying Weeds Common in Sacramento Valley&What strategies makes sense Q&A –Brad Hanson, Weed Specialist, UC Davis
2:20 Poisonous weeds in alfalfa – Nitrates, alkaloids and tannins: What are the keyones that affect animals?—Birgit Puschner, UC Veterinary College, UC Davis
2:35 Estimating the true water needs of alfalfa and using ET to schedule Irrigations–Daniele Zaccaria, Irrigation Specialist, UC Davis, CA
2:50 Kura Clover – Introduction of a new crop – the importance of being patient–Dan Putnam, UC Forage Specialist, UC Davis, CA
2:55 Switchgrass Plantings for Biofuels—Dan Putnam, UC Davis
3:00 Choosing Alfalfa Varieties for Maximizing Pest Resistance and Yield—Dan Putnam, UC Davis
3:15 Low Lignin Alfalfa – A New Technology coming along - Current and Future UC Experiments – Brenda Perez, UC Graduate Student, UC Davis
3:30 Drip Irrigation Studies in Alfalfa—Ali Montazar, Department of Plant Sciences, UC Davis
3:45 Breeding and Evaluation of Fall Dormancy in Alfalfa – Charlie Brummer, UC Davis
4:00 Deficit Irrigation of Alfalfa and Interactions with varieties—James Radawich, Graduate Student, UC Davis
4:20 Return to Base/h2>
To say it has been a strange year would be par for the course. When don't we have a strange year anymore?! To say it has been a wet year, however, would be an understatement. According to the National Oceanic and Atmospheric Association, normal rainfall for the “water year” (October 1st through September 30th) is 14.06 inches for Stockton, CA. Last winter, we received 15.29 inches in Stockton from October 1st to April 11th. This year, we have received 20.75 inches to date.
With the high rainfall, we have received many inquiries about how to manage poor stands of alfalfa. Dan Putnam, UC Alfalfa and Forage Specialist, anticipated these sorts of problems early in the year and posted this article to the Alfalfa and Forage News blog. With this posting, I follow up with a Q&A of things I've heard and discussions I've had since that article was written. Remember that every situation has its unique set of conditions, and recommendations should be site specific.
1. There are poisonous weeds (e.g. groundsel, fiddleneck) in spots of the fields where the stand is poor. The weeds are not widespread, but they are no longer seedlings. What can be sprayed on these weeds?
Rachael Long, farm advisor in Yolo, Solano, and Sacramento counties, described these weeds and some treatment options in a recent article. In this particular example, where the weeds are not widespread and probably too big for effective herbicide treatment, an option could be to cut those portions of the field and get rid of that weed-infested hay. The rest of the field could be cut and baled as usual. Once groundsel and fiddleneck have been cut, they will have a hard time competing with the alfalfa plants in subsequent regrowth and cuttings.
2. A grower generally cuts a field for the first time around the first week of April. The stand was still pretty short at that time. If the grower stayed on his typical schedule, would cutting when the alfalfa is short stimulate growth, or would it be better to wait to cut?
If the field has poisonous weeds, as described in Question 1, an early cutting might be appropriate, especially if the weeds are widespread in the field. The grower could cut early to manage the weeds, and since the hay is short, the grower would not lose a lot of yield. If the stand is clean of weeds, however, it would probably be advisable to put off the first cutting. Letting the plants grow, and perhaps go to an early stage of flowering, would help the root system develop and strengthen the plants.
3. Many growers and consultants have heard that alfalfa produces autotoxins, which cause poor establishment of overseeded alfalfa. How long do the autotoxins remain in the soil?
Autotoxicity is the effect of a chemical compound released by plants of the same species. The autotoxic effect can last in the field as long as there are decomposing crowns. Once the plant material has decomposed, the autotoxic effect doesn't usually last. Remember that there is also general competition between older/bigger alfalfa plants and young seedlings. This is not related to autotoxicity, but rather to the fact that seedlings are small and weak compared to the strong, multi-stemmed crown of a mature alfalfa plant.
4. Does overseeding alfalfa ever work?
I previously wrote an article on overseeding older alfalfa stands, and Dan Putnam wrote this article on this topic. Growers may overseed older alfalfa stands with grasses or legumes to prolong stand life, but of course, this year has presented extraordinary conditions where growers are considering what to do with poor stands that are of varying ages – even seedling fields planted last fall! Generally, we wouldn't recommend overseeding unless the current stand has less than 6-10 plants/ft2. In a situation where that was the case, both Dan and Mick Canevari, emeritus farm advisor in San Joaquin County, have seen poor stands of seedling alfalfa be successfully overseeded under certain conditions, namely, the seed was drilled into the previous stand and was planted to moisture. Additionally, having the option of sprinkling up the newly-planted seed can help in successful establishment. Remember that overseeding can sometimes lead to complicated weed management. Consider your weed management program (for the old part of the stand and the newly-planted part of the stand) before going to the effort and expense of overseeding.
5. A grower applied a herbicide in December with a 12 month plant-back, according to the label. Now, with all the rain, the stand looks really poor, and the grower wants to take out the alfalfa and plant something else. What should the grower plant?
Remember, the label is the law. If the label says there is a 12 month plant-back, then what that means is that there could be phytotoxic effects to a subsequent crop that is planted within 12 months. Sometimes, however, the label may specify shorter duration plant-backs for certain crops. Be sure to read the label carefully.
6. For fields that have had a history of problems with stem nematodes, is a poor stand from all the rain or from stem nematodes?
Unfortunately, this is probably a collision of both problems, and neither has a great solution. For reasons previously described, there are not a lot of solutions for poor stands resulting from saturated conditions. Likewise, there are not a lot of solutions for fields having stem nematode, regardless of whether the soil is saturated or not. Stem nematodes cause most of their problems when soils are cool and moist. We notice their impact in the spring when regrowth is poor, as with shortened internodes and possibly white flagging of stems. Once conditions have warmed, stem nematodes recede deeper into the soil and tend to not be a problem later in the year. The ways we can deal with stem nematode are limited but include planting highly-resistant (HR) varieties and having good equipment sanitation between infected and non-infected fields.
7. A grower has an alfalfa field where a portion of the field is in very poor shape, but the rest of the field looks ok. What could this grower do?
Dan Putnam and I recently visited a field in the Delta where this was the case. In fact, it was the higher end of the field where the stand was basically decimated, but over the winter, there was pretty pervasive standing water in much of the Delta. In this particular situation, the grower produces the alfalfa for his own dairy and can manage the field selectively. The grower will probably disc up the end of the field where the stand is bad and plant sudan there. He'll bale the sudan and then plant alfalfa there in the fall. This option seemed amenable to the grower, but of course, every grower is going to have a different set of costs, buyers, and circumstances.
There is no “one size fits all” on these questions. Every situation will have a slightly different recommendation depending on the conditions. Even as the spring turns to summer, we may still see alfalfa fields dying back as a result of the wet winter we've had. Keep the questions coming, but let's hope we can move forward into a productive spring and summer!
A consultant recently brought in some alfalfa plants to get another opinion on why growth was resuming slowly this spring. The field is located in Merced County and is a sandy loam soil. The field is in its fifth year, is glyphosate-tolerant, and has traditionally produced high-quality hay. About 5 acres of a 40-acre field are affected.
There are many reasons why growth may resume slowly this spring. The obvious reason, of course, is that we received a lot of rain this winter. With that rain has come associated problems from cool, anoxic (lack of oxygen) soil conditions. A previous blog article describes things to look for in alfalfa fields where there was standing water this winter, and how to diagnose problems as the weather warms and soil dries out. In this particular example, the consultant assessed soil conditions by augering down about four feet. He did not observe excessive moisture, even down to four feet, and generally, we would presume fairly good drainage from a sandy loam soil. He also sent samples to the lab for chemical analysis. The soil analysis indicated an acceptable pH (7.6), low salinity (EC 0.5-0.8 dS/m), adequate soil phosphorus (12 ppm), and marginal to low potassium (45 ppm). Despite the low potassium, no potassium deficiency symptoms have been observed on the leaves. The grower applied turkey manure to the field in the fall but did not have it analyzed, so we do not know its fertility characteristics. Additionally, the grower applied herbicides in the fall. There has been some concern that the affected acreage is reacting poorly to the herbicides; however, when herbicide damage has occurred, we would generally expect to see the damage over the entire treated acreage, and that is not the case in this field.
Earthworms do not feed on roots, but rather, ingest the soil and its microorganisms, mixing the soil as they feed. A recent California Agriculture article discusses how soil biodiversity contributes to soil health, defined as soil functionality. Earthworms certainly are a component of soil biodiversity, and their presence often relates to beneficial soil physical and chemical characteristics. While the jury is still out on what might be causing the slow spring growth of this alfalfa field, I think we can rule out these little, white orbs.