Desert Research and Extension Center
Desert Research and Extension Center
Desert Research and Extension Center
University of California
Desert Research and Extension Center

Alfalfa and Agronomic Crops


ANR Alfalfa Blog

UC Davis Alfalfa Page




Dan Putnam (, Chris DeBen, Eric Lin, UC Davis, and Sam Wang, UC


How much Nitrogen Does Alfalfa Produce? Alfalfa produces a surprisingly high quantity of nitrogen (N) per year, the most likely range from about 400 lbs to 700 lbs N per acre in California depending upon yield and crude protein concentration of the crop (Table 1). Most of this N is removed in the crop, but some portion remains to benefit the subsequent crop. Virtually all (likely over 80-90%) of this originates from the atmosphere through biological N2 fixation. This is valuable since alfalfa requires zero fertilizers, but it also valuable to meet the N needs of a subsequent crop in rotation.

But how much “N-credit” should be given to a grain crop in rotation?

 Rotation Studies in California: Over the past several years, we have been conducting rotation studies with alfalfa. Our objectives were to develop an ‘N credit’ recommendation for N fertilizers in non-legumes rotated with alfalfa. Locations are Davis (Yolo County), Parlier (Fresno County) and Tulelake (Siskiyou County). The first data is coming off of the plots this spring, and it will continue through 2014 and 2015.

Analysis: Rotation Effects between crops are complex. Rotation is generally thought to be highly beneficial, since disease cycles are interrupted, weed infestations may differ, in addition to the nutrient benefits of a legume-non-legume rotation. In this study, we may be able to differentiate between an “N-effect’ and the “non-N” effects of rotation, as per the graph shown

(Figure 1). The non-N effects may be shown by some increase (or decrease) in wheat yields, even after the full N needs of the crop are met in the alfalfa-wheat rotation compared with the grains-wheat rotation. There are also possibly some negative effects, such as allelopathy from a rotated crop. 



Dan Putnam and Oli Bachie, UC Davis and UCCE.


Almost like getting married! Choosing a variety is a

little like getting married - after all, you’ll need to live with

that decision for a long time. Why not take a little time to

determine whether an alfalfa variety is a good one?


El Centro Trials: A University of California Variety trial

was planted in 2012 on the heavy soils at the Desert

Research and Extension. This is a part of the state-wide

variety evaluation testing, which has 8 locations in

 Which variety to choose? Growers often choose

cultivars based upon promotion, price or habit. However,

the choice of a variety can make a large long-term

difference in profitability. Spending just a few minutes to

carefully consider choice of variety may be beneficial,


1) Cultivars can have a large impact upon yield

2) Varieties can help cope with diseases or insects

3) Growers are ‘stuck’ with their choice for

many years.

UC Variety Testing Program. The University of California provides an independent source of

variety information that can be used to judge performance of alfalfa varieties. We have plots at

Tulelake and Scott Valley (Intermountain), Davis, Modesto and Kearney and West Side (Central

Valley), and El Centro (Desert).

Yields are important, but are not the only criteria for variety selection. Take a look at fall

dormancy, disease resistance, and the quality characteristics, too. Research is continually

underway to improve the performance of alfalfa varieties.

See: , for current variety information


Alfalfa Experimental Germplasm and Cultivar Adaptation and Evaluation


Dan Putnam, Extension Agronomist, Dept. of Plant Science, UC Davis, CA 95616  530-752-8982   Francisco Maciel, SRA, DREC, El Centro, CA

Craig Giannini, SRA, Davis, CA


Alfalfa variety testing and variety choice continues to be of vital interest to growers and seed producers in California.  A new trial was planted in Fall, 2012, and will be harvested at DREC in 2013, and should be harvested through 2015.  This trial will not include Roundup-Ready varieties due to concerns about co-existence issues.  Approximately 36 varieties were planted in 6 replications.  This trial at DREC is a component of a state-wide effort.  Currently, we have trials at: Tulelake, Davis, Modesto, Kearney, West Side and El Centro.    Results of these trials will be reported at:, and used for newsletters and field days.



Industry plant breeders enter experimental cultivars in the trials to obtain performance data for further breeding.  This data can be used as documentation in applications for cultivar approval by the Alfalfa Variety Review Board and for Plant Variety Protection. Growers depend on University data to help make variety choices, and to check on information supplied by companies.   

The UC California Alfalfa Variety Testing Program is probably the largest and most comprehensive of any western state.  It is a well-respected source of information on varieties for other western states as well as California.  The desert California data is used throughout other regions with similar climates, such as Arizona, New Mexico, but also Australia and S. America.

University Cooperative Extension Farm Advisors use the data to make recommendations. University researchers rely on this data to provide tests of experimental germplasm, as well as controlled yield tests for economic and other analysis. 

California is ideally situated to test alfalfa varieties in a wide range of environments.  These trials provide information critical to University and industry plant breeders, farm advisors and growers.  It is the major independent source of unbiased information on alfalfa cultivars for western-adapted lines.

The El Centro trials are useful not only to California growers (those in the Imperial Valley of California) but also to growers in the Palo Verde Valley, to some degree to growers in the Southern San Joaquin Valley, and internationally to growers and seed people in the Middle East, Mexico and Argentina.

Cultivar evaluation is a critical aspect of variety improvement.  The information we develop about the performance of these materials provides both growers and farm advisors with a realistic assessment of the potential of each cultivar.  It also provides a historical record of the progress in improving performance. Materials in each trial are all certified cultivars that are commonly sold in the region or cultivars likely to be certified in the near future.

Economic returns from variety selection are high.  These have been documented to be well over $1200/acre over the life of a stand.   In the Imperial Valley, these differences are worth potentially millions of dollars per year.


Biofuels/Oilseed Crops


Canola and Camelina: Winter oilseeds as alternative crops for California


Nicholas George, Joy Hollingsworth, Oli Bachie & Steve Kaffka


Winter crops are advantageous for California farmers because they grow during times of lower

transpiration and can make use of rainfall, however California has few economically viable cool-season

crops. Canola (Brassica napus) and camelina (Camelina sativa) are oilseed crops that could diversify

winter rotations. Our project is evaluating the potential of these species as crops for

California growers.

(picture page 8 of pdf)



Steve Kaffka




Principle Researcher: Dr. Sam Wang


Lesquerella (Lesquerella fendleri) is a member of the mustard family and is native to the

southwestern United States and northern Mexico.

The oil in lesquerella seeds can be used as diesel additive and a number of other bioproducts

such as lubricants, motor oils, plastics, inks, and adhesives.

The hydroxylated oil in lesquerella is similar to castor oil but does not contain the deadly poison

Lesquerella can be planted similar to alfalfa and harvested using regular combine.


Sorghum as a low-input crop for bioenergy, food and feed in California


Dr. Jeff Dahlberg, Director, UC-ANR-KARE, 9240 S. Riverbend Ave., Parlier, CA 93648 phone: 559-646-6060,


Dr. Oli Bachie, Agronomy Advisor, UC-CCES-Imperial County, 1050 E. Holton Road, Holtville, CA 92250 phone: 760-352-9474, Drs. Bob Hutmacher, Bill Orts, Peggy Lemaux, and Mr. Steve Wright


Sorghum [Sorghum bicolor (L.) Moench] is a globally important crop, ranking as the fifth most important cereal crop in the world in terms of total production. The United States is the world’s largest sorghum producer and consequently there is an existing research and development capacity dedicated towards the crop. The majority of US sorghum production is in Kansas and Texas, with only limited production in California. Despite this, sorghum is an attractive crop for the state - sorghum can remain productive under comparatively low water and nutrient conditions, and also produces biomass that is well suited for the production of useful products such as bioenergy and livestock feed, and well as grain suitable as either a nutritional food-stuff or biofuel feedstock. Sorghum could therefore help reduce irrigation and nitrogen fertilizer use in California whilst maintaining productive agricultural out-put. This project therefore aims to facilitate the increased use of sorghum as a multi-purpose low-input crop for the state.


Sorghum [Sorghum bicolor (L.) Moench] is a globally important crop, with the USA as the largest producer. The majority of sorghum production is in Kansas and Texas, with only limited production in California (USDA NASS, 2011). Sorghum can be an attractive crop for arid and semi-arid areas because it is productive under comparatively low water and nutrient conditions and because many types of sorghums can remain productive when exposed to temporal water stresses associated with reduced rainfall or deficit irrigation. For example, multiple studies have demonstrated that water use of sorghum can be two-thirds or less than that of corn with similar biomass productivity (Marsalis and Bean, 2010). Sorghum biomass is suited to various end uses, including silage and biomass feedstocks (Dahlberg et al., 2011a; Marsalis and Bean, 2010). The dairy industry is one of the most important sectors in California agriculture generating around $6 B in total income in 2011. The estimated industry value to the state is $63 B annually, plus supporting over 400,000 jobs (Ellerby, 2010; USDA NASS, 2011). Extensive acreage is dedicated to silage corn production in California to meet the feed demand of the dairy industry. Over the past decade, silage corn acreage has increased from 400 thousand acres to over 500 thousand acres (USDA NASS, 2011). In the face of ongoing water constraints and pressure on the dairy industry to reduce input costs, sorghum is an attractive lower-input alternative to current corn acreage. As a biofuel crop sorghum has several advantages. There exist long-standing sorghum R&D programs and seed suppliers. Its agronomy, breeding and genetic structure are already well established. Sorghum is an annual crop and can therefore be readily integrated into existing cropping systems and provides flexibility to growers relative to perennial biofuel choices. Sorghum can achieve dry biomass yields of 20 T/ha (Dahlberg et al., 2011b), and in fact the US Department of Energy project that identified the potential of switchgrass as a biofuel feedstock explicitly acknowledged that sorghums have near-comparable productivity (Wright, 2007).  The proposal addresses several goals of the Sustainable Food Systems Initiative: (i) The investigation of new crops that have the potential to grow well in California, particularly as the climate changes; (ii) Developing farm products that directly support biofuel development; (iii) The introduction of plants specifically for water-limited conditions; (iv) Science-based information acquisition to enhance the competiveness of California’s agricultural producers, and (v) Developing management systems and production techniques to improve nitrogen use efficiency via the use of the APSIM model.


Sorghum can use up to 2/3 less water than corn to produce similar biomass. 




Cellulosic Ethanol: Multi-Site Evaluation of Saccharum Hybrids and Other Potential Biofuel Feedstocks


David Grantz,  Khaled Bali, Steve Kaffka, Tom Tew


Increasing attention is being given to locally grown and processed biofuels in response to national security issues and recent California legislative and executive actions. We have been evaluating a wide variety of sugarcane and relatives as purpose planted biofuels of interest to the locally developing cellulosic ethanol industry in the Imperial Valley. Grasses of the Saccharum complex, including commercial clones (90% S. oficinarum and 10% S. spontaneum) have been evaluated initially. Yields have been high at  DREC . Clones with up to 50% S. spontaneum, called energy canes, have yielded even more. type I energy canes maintain enough sugar to provide both a sugar and cellulosic feedstock stream. type II energy canes provide too little sugar to be of interest, but may have greater biomass potential for a purely cellulosic feedstock stream. In the current year yields will be determined on a subset of 3 sugarcane and energy cane clones, with careful monitoring of water use under drip irrigation.  In addition to the sugarcane, we are growing a large field of sorghum, which can serve as a cellulosic biofuel feedstock. In this field we monitor continuously gas exchange with the atmosphere as well as carbon and nitrogen emissions from the soil. We are using a data-model fusion technique to improve mathematical characterization and modelling of the greenhouse gas implications of biofuell production in the low desert.


The project at  DREC is targeted at an area of current economic vulnerability. The developing biofuels industry may be a major factor in its economic regeneration, as the region has a traditional agricultural economy. The proposed research, as part of the larger biofuel effort in California, will be essential to support the development of these industries in distinct bioclimatic regions of California. Key shortcomings of available business plans for biofuels industries in California are lack of year-round biomass feedstock (regardless of fermentation technology and biofuel endproduct) and a locally available biomass feedstock to avoid transportation costs. The proposed research addresses these problems by examing sugarcane and energy canes, with a winter harvest schedule, and sorghum with a summer/fall harvest schedule. The PIs have extensive experience with sugarcane and forage crop cultivation, with crop physiology, and with assessment of crop water use. Current progress in developing low sugar and high cellulose clones of Saccharum complex species suggest that further selection for local adaptation is feasible. The sorghum study will allow quantification of the net greenhouse impact of biofuel production under productive Imperial Valley conditions. .



Wheat Breeding for the Imperial Valley  


Jorge Dubcovsky, Professor, Department of Plant Science, University of California, Davis CA 95616, 530 752 5159 

Oswaldo Chicaiza, Alicia del Blanco, Phil Mayo, Diane Prato-Mayo, Francisco Maciel;


Wheat is an important component of the winter cropping system in the Imperial Valley, providing needed alternatives in crop rotations and economic viability with relatively low input. Imperial Valley is one of the main production areas of Desert Durum ® in California. The main objective of this proposal is to develop wheat varieties and germplasm adapted to this region. A continuous breeding effort is required to maintain an adequate supply of varieties resistant to new pathogens (e.g. stripe and leaf rust) and adapted to growers and industry needs. We will continue the traditional breeding efforts. The evaluation of the durum breeding lines at the DREC is essential to select varieties adapted to the main region where Desert durums are grown. Every year we will produce ~150 new hybrids combining different lines. The best lines from the segregating populations are tested in yield trials at DREC. The Regional testing program will provide detailed comparisons among available commercial varieties and new breeding lines. The field based breeding program will be supplemented by a marker assisted selection project aimed at improving disease resistance and salt tolerance and reducing cadmium content, increase protein and gluten strength and increase resistant starch content in the grain. We will also evaluate common and durum lines for improved resistance to drought.


In 2012, the most recent year with available USDA statistics, California produced 14,175,000 bushels of pasta wheat with a farm value of $136,800,000 (, a value that was then multiplied several times by the pasta industry. California pasta wheat generates numerous jobs and a valuable income to the State through exports. Durum wheat grown at the Imperial Valley and the San Joaquin Valley has a special trade mark, “Desert Durum®”, which has built an international reputation for high-quality and trades at premium prices.


The continuous evolution of new races of several diseases requires a continuous effort to incorporate new resistance genes. New races of stripe are virulent on several durum varieties (e.g. Kronos). In addition a new virulent race of leaf rust has appeared in Mexico and a new virulent race of stem rust is slowly spreading from Africa. The incorporation of disease resistance genes into the wheat germplasm adapted to the Imperial Valley is essential to maintain a viable crop.


In addition new requirement of lower cadmium levels are urgently needed to meet EU requirements. The soils in the desert valleys and lowlands of Southern California are rich in Cd, and the intensive use of phosphate fertilizer may increase these levels even further. Cd is a non-essential heavy metal that is easily absorbed and translocated in plants 8, particularly in durum wheat, which is not as efficient as bread wheat in limiting Cd translocation from the roots to the grains. In 2012, more than 90% of the durum wheat acreage planted in California consisted of high-Cd varieties. This high proportion of high-Cd varieties jeopardizes future exports to the European Union and other international markets, and also imposes an unnecessary health risk for Californians.


The Codex Alimentarius Commission of the FAO has recently reduced the maximum level of Cd to 200 ng/kg, and the European Union (EU) has adopted this guideline for its imported and locally grown pasta wheat. Unfortunately, when Desert Durum wheats are grown in the high-Cd soils of Southern California, their Cd content usually exceeds this recommended. Efforts to produce low-Cd cultivars for different crops are recent, and market restrictions have been the major forces driving this change. Fortunately, grain Cd content is a trait with high heritability (0.84-0.88) and in wheat is mainly controlled by a single locus designated Cdu1, which limits the translocation of Cd to the shoots. It has already been demonstrated that the incorporation of the Cdu1 low-Cd allele into adapted durum wheat varieties from Canada was not associated with negative effects neither on agronomic performance nor on the uptake of other micronutrients.

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