- Author: Michelle Leinfelder-Miles
Lately, I have been corresponding with growers and consultants about slow spring growth in their alfalfa fields. There are several reasons why growth may resume slowly this spring. I describe them below and discuss some way we may be able to manage for them.
Roland Meyer, UC Soils Specialist Emeritus, provided this information regarding water-run inoculum: it does not work well because the inoculum is not water soluble and floats to the surface. Rather, better success with re-inoculating fields comes with applying additional alfalfa seed coated with inoculant. The field needs to be irrigated soon after broadcasting the seed to get the inoculant into the soil.
Dormancy. I think we have a tendency to look over the figurative fence at neighboring fields and make comparisons. Keep in mind that the dormancy rating of a variety will have an influence on whether the field “wakes up” early in the season or tends to start growing a little bit later.
Nutrients. Nutrient management involves complex decision making and an understanding of agronomy, soils, and economics! When commodity prices are low, it can be hard to justify input expenses, but keep in mind that alfalfa is a perennial crop with perennial nutrient needs for maintaining yield and quality. Fall is the best season for addressing alfalfa fertilizer needs, particularly phosphorus (P) and potassium (K). There are soils in this region, especially in the Delta, that are low in K. We suggest soil sampling in the fall to gain an understanding for nutrient availability and then, as needed, applying fertilizer between October and February because it could take 60-90 days for the crop to fully respond to fertilizer application.
A couple other considerations for K nutrient management:
1) In new stands where the taproots may not yet be deep, soil sample in the top 12 inches to determine K availability. I have heard that some folks may be sampling down to 24 inches in alfalfa fields because they know alfalfa grows long taproots. While a mature stand will have developed taproots and may be able to scavenge for nutrients that deep, a younger stand probably cannot, and sampling too deep may give a false impression for nutrient availability.
2) Even when the soil test indicates adequate K, some K fertilizer may be needed in high-yielding crops. Alfalfa has a long growing season, and therefore, a long season of nutrient demand. Each cutting removes large amounts of nutrients with the plant tissue.
Use these rates to guide your K fertilizer applications – remembering that soil type, climate, and yield will influence fertilizer needs – and keep good records of all laboratory results, fertilizer applications, and crop observations. These records will be helpful in developing a long-term, economical fertilization program that maintains alfalfa yield and quality year after year.
Sending everyone best wishes for the season, and don't hesitate to reach out if you have questions or comments.
- Author: Michelle Leinfelder-Miles
Here are a few announcements from UC Cooperative Extension. Please don't hesitate to reach out to me with any questions.
1. UC Cooperative Extension in San Joaquin and Stanislaus counties is partnering with the American Farmland Trust (AFT) to connect women landowners with resources, information, and a network. Women for the Land is an AFT program that began in the Midwest and Mid-Atlantic states, providing women landowners with information for land conservation. The meeting details are below, and documents are attached at the bottom of this post. Please share the flyer with interested women in our region!
- Tuesday, March 26, 2019. 1:00-4:00pm. Cabral Agricultural Center, 2101 E. Earhart Ave., Stockton, CA 95206. To register, visit: farmland.org/SanJoaquinCountyLearningCircle or call 916-448-1064.
- Wednesday, March 27, 2019. 1:00-4:00pm. Stanislaus County Agricultural Center, 3022 Service Rd., Modesto, CA 95358. To register, visit: farmland.org/StanislausCountyLearningCircle or call 916-448-1064.
2. UC Cooperative Extension is hosting two Weed Science field days in the San Joaquin Valley. Event details are below, and flyers are attached at the bottom of this post. The events are free, but space is limited, and registration is required by calling the UCCE Merced County office at 209-385-7403. Pesticide applicator continuing education credits are available at each event (3.5 units).
- Tuesday, April 2 2019. 8:00am-12:15pm. Kearney Agricultural Research and Extension Center, 9240 South Riverbend Road, Parlier CA 93648
- Thursday, April 11, 2019. 8:00am-12:15pm. Westside Research and Extension Center, 17353 West Oakland Avenue, Five Points, CA 93624
3. The UC Pest Management Guidelines for dry beans have been updated. The guidelines provide information on 19 insect pests, 18 diseases, 6 abiotic disorders, nematodes, and weeds, including a new table of registered herbicides and timings for dry beans.
AFT Women for the Land Brochure
AFT Women for the Land San Joaquin County Flyer
Weed Science Field Day at Kearney
Weed Science Field Day at Westside
- Author: Michelle Leinfelder-Miles
- Right source: selecting the fertilizer source that matches the crop need and minimizes losses,
- Right rate: applying the right amount based on crop need and nutrient availability through other sources,
- Right time: applying the nutrient when the crop can use it,
- Right place: fertilizer placement that optimizes the crop's ability to use it.
The four R's address management considerations (e.g. fertilizer program, irrigation), but site characteristics (e.g. soil, cropping system, weather conditions) also influence N recovery in the crop. Also important to improving crop N recovery is understanding barriers to adopting best management practices, such as costs or risks to crop quality or yield.
While the four R's articulate four principles for N management, the N cycle in cropping systems is complicated. Nitrogen can be introduced and lost by various paths. We generally add N with organic matter amendments – such as crop residues, compost, or manure – or with fertilizer. While organic matter amendments must be mineralized before the N is available for plant uptake, fertilizer N is readily available for plants to use. That said, plants generally take up N at different stages during their life cycle, and there is a risk for N loss if the N is applied or becomes available when the plants do not need it.
Technologies have been developed to mitigate N losses from cropping systems. These technologies are collectively known as enhanced efficiency fertilizers (EFF) and include additives, physical barriers, and chemical formulations that stop, slow down, or decrease fertilizer losses. Nitrogen stabilizers are one example and are fertilizer additives intended to improve crop N use efficiency and reduce N losses to the environment by interrupting the microbial processes that change N to its plant-available forms. We developed a trial to evaluate two N stabilizer products with the objective of determining whether the treatments improved corn silage yield or plant N status compared to fertilizer alone. We did not attempt to measure N losses from the system (e.g. leaching, denitrification), as these are very challenging to quantify.
The trial took place in San Joaquin County on a DeVries sandy loam soil. A description of the methods can be found in the full report. Sidedress fertilizer application occurred on June 21, 2018 and provided approximately 105 lbs N per acre (UAN 32). Four treatments were applied at sidedress, when plants were at V3-4 stage of development (Figure 1). The N stabilizers were applied at the label rates, and the treatments were: 1) Vindicate (Corteva Agriscience) at 35 fluid ounces per acre, 2) Agrotain Plus (Koch Agronomic Services) at 3 pounds per acre, 3) combination of Vindicate and Agrotain Plus at aforementioned rates, and 4) fertilizer-only, no stabilizer product (“untreated”). Treatments were randomly applied in three replicate blocks. Aside from the treatments, the trial was managed by the grower in the same manner as the field.
We evaluated soil N status, plant N status, and silage yield. Soil results are available in the full report. There were no statistically significant differences in plant N status or yield (Table 1). Mid-season (i.e. silking, R1) leaf N averaged 2.88 percent across treatments, and aboveground biomass N at harvest averaged 1.12 percent. At mid-season, leaf N from 2.7 to 3.5 percent indicates that the plant had sufficient N to carry the crop to harvest, and at harvest, aboveground biomass N from 1.0 to 1.2 percent indicates that the N fertilization program was adequate for maximizing yield. Thus, it appears that the trial was not deficient in N. Calculated to 30 percent dry matter, average yield across treatments was 38.8 tons/acre, and dry matter was 35 percent. There was a trend for the two treatments with Vindicate to have higher N removed than the two treatments without it, but the difference was not statistically significant.
In summary, N is part of a balanced, natural cycle in the environment and is the most important nutrient in cropping systems. Giving consideration to N management will help ensure that a greater fraction of the applied N is recovered in the harvested crop and not lost to the environment, and keeps growers in regulatory compliance. Enhanced Efficiency Fertilizers, such as N stabilizers, have been shown to improve crop yield in regions like the Midwest and the Northeast, and may help to mitigate N losses to the environment. In our trial, we evaluated the efficacy of N stabilizer products for improvements in corn silage yield or plant N status compared to fertilizer alone. Under the management and environmental conditions of this trial, we found no differences in yield or plant N status; however, plant and soil tests indicated that N was not limiting in the trial. If N was lost from the system, the loss was not large enough to result in N limitation in the control. Future study should test these products using different N sources and N rates (e.g. grower rate versus grower rate minus 50 lbs N/acre). It may be possible to reduce the fertilizer N rate without sacrificing yield.
This trial was made possible with the generous cooperation of Hank Van Exel and Van Exel Farms; Carl Bannon and Steven Colbert (Corteva Agriscience); Brad Schrenk (Simplot); Eric Ellison (Koch Agronomic Services); Nick Clark and Daniel Geisseler (UCCE); and Shirley Alvarez, Cheryl Gartner, and Dan Rivers (UCCE technicians). An in-depth report is available from my website. Please don't hesitate to contact me with comments or questions.
/span>- Author: Michelle Leinfelder-Miles
On Thursday, January 17th, I hosted the annual SJC and Delta Field Crops Meeting in Stockton, CA. I want to thank everyone who attended and provided feedback on the meeting. Your evaluations are critical and inform Cooperative Extension outreach efforts! The presentations from that meeting have now been posted to my website. I encourage you to reach out to the presenters with questions. Also available from my website are full reports of local research trials, including the Delta field corn variety trial. I will make an announcement here on the blog when new reports are available.
UC statewide specialists make their research results available through the Agronomy Research and Information Center (RIC) website. Please check the RIC for information on statewide trials in small grains, alfalfa, dry beans, and other field crops.
We hope you will find this information useful, and we hope you will share your feedback with us so that we may best serve your interests for research and outreach.
- Author: Michelle Leinfelder-Miles
Happy New Year! We are entering "meeting season". The new year brings several opportunities for continuing education, including UC Cooperative Extension grower meetings and the California Plant and Soil Conference. Please see below for more information.
1. UC Cooperative Extension will host the SJC and Delta Field Crops Meeting on Thursday, January 17, 2019 from 8:00am to 12:00pm. The meeting location is the Cabral Agricultural Center in Stockton (2101 E. Earhart Ave., Stockton, CA 95206). Please see this previous post for the agenda or open the attachment below. We will offer continuing education credits for DPR licensing (2), CCA certification (3), and nitrogen management (1.5). Light refreshments will be provided.
2. UC Cooperative Extension will host five meetings for rice growers. The meeting details are as follows:
Richvale: Thursday, January 17, 8:30am, Evangelical Church, 5219 Church St., Richvale
Glenn: Thursday, January 17, 1:30pm, Glenn Pheasant Hall, 1522 Hwy. 45, south of Glenn
Colusa: Friday, January 18, 8:30am, Colusa Casino Resort, 3770 Hwy 45, Colusa
Marysville: Friday, January 18, 1:30pm, Yuba County Government Center, 915 8th St., Marysville
Woodland: Tuesday, January 22, 8:30am, Cracchiolos Banquet Hall, 1320 E. Main Street, Woodland
Time: Doors open at 8:00am, and meetings start at 8:30am at Richvale, Colusa, and Woodland. Doors open at 1:00pm, and meetings start at 1:30 pm at Glenn and Marysville. DPR and CCA continuing education credits will be offered. For the program, please visit the UC Rice Blog.
3. The California Chapter of the American Society of Agronomy will hold its annual Plant and Soil Conference on February 6-7 in Fresno, California. Program information and registration are available from the conference website. Session topics include water management, climate smart agriculture, irrigation efficiency, and pest management. DPR licensing, CCA certification, and nitrogen management continuing education credits will be offered.
SJC and Delta Field Crops Meeting Agenda