Chapters 5.49

5.49 -Use of Alfalfa for Smallholder Farmers to Increase Resiliency to Climate Change

Meghan Glavin, University of Guelph, Canada

Suggested citation for this chapter.

Glavin,M. (2022) Use of Alfalfa for Smallholder Farmers to Increase Resiliency to Climate Change, In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org

Introduction to Alfalfa

Alfalfa (Medicago sativa, also known Lucerne) is a very well-known forage crop that is grown worldwide primarily for livestock and soil restoration, and has potential to help smallholder farmers combat climate change. Alfalfa is native to Southwestern Asia and was introduced into western Europe after the invasion of the Romans (Brough, 1977). Due to the crop’s popularity around the world today, there are a diversity of alfalfa varieties available including those with enhanced salt tolerance, drought tolerance, or soil acidity tolerance and/or resistance to disease and pests (Undersander, 2011).

Alfalfa see can be obtained from commercial seed companies, with detailed varietal information available from commodity organizations in different countries (e.g. U.S. National Alfalfa and Forage Alliance). Alfalfa does best on well-drained soil, heavy clay soils and requires a neutral pH ranging from 6.5 to 7.0 (Undersander, 2011). Seedling establishment is very critical; poor timing and conditions can lead to low yields, shorter stand life, weed pressure and reduced forage quality (Mueller, 2005). Alfalfa germinates best in a soil temperature between 18 and 29°C and experiences optimum growth during the first month when temperature ranges between 20 and 24°C (Mueller, 2005). In regard to rainfall requirements, once again it is highly dependent on the variety, as some can survive droughts and some yield higher in wetter conditions (especially disease tolerant varieties). In general, however, alfalfa requires 800-1600 mm/growing period; the variation of water requirements depends on the cutting interval – the crop requires more water with more cuttings (FAO, 2020).

Weed management can be a challenge when growing alfalfa, however, there are many solutions. Alfalfa can be companion cropped, with crops such as annual ryegrass, oats, and spring barley; together these can reduce weeds, help control erosion, reduce seedling damage and minimize weed competition (Undersander, 2011). Although weeds are not typically a problem if the stand’s foliage is dense enough, Roundup Ready alfalfa is another tool that can be used in order to fight a weed problem without sacrificing the crop (Undersander, 2011). Many farmers choose to integrate alfalfa into their crop rotations due to its benefits on the fertility of the soil. Alfalfa is typically cut mid-bud and is cut multiple times in a growing season. As a result, growing alfalfa can be very labour extensive. Alfalfa is typically baled using twine for storage; however, the moisture content of the alfalfa should be around 20% so farmers should be careful when they harvest.

Nutrients

The nutrient composition of Alfalfa can vary depending on the variety and when the alfalfa is cut. Early cut alfalfa can vary from 16 to 20 percent crude protein as compared to late cut alfalfa which typically contains 12 to 15 percent crude protein (Foster, 2009). Alfalfa is high in the amino acids Lysine, Leucine, Valine, and Arginine, but deficient in Methionine, Tryptophan and Cysteine (Food and Agriculture Organization of the United Nations, 2012). The fiber content ranges from 20 to 28 percent in alfalfa hay. In the case of beef cattle, one pound of alfalfa per 100 pounds of bodyweight, will supply the animal’s daily requirement for calcium, magnesium, potassium, sulfur, iron and zinc (Foster, 2009).

Uses of Alfalfa

Alfalfa is an important forage for livestock due to its high nutritional value and protein content. Alfalfa is able to support livestock, which benefits smallholder farmers in terms of high value meat or milk, labour and as a source of manure (source of nitrogen, potassium, phosphorus, soil organic matter) (Shirani, 2002). In the absence of feed, such as in the dry season, many farmers are forced to sell/slaughter their livestock at a low cost (Government of Western Austrialia, 2019). Because alfalfa feed can be dried and stored at room temperature while retaining nutrients, it has the potential to be useful during extended dry seasons when livestock are most vulnerable to hunger.

Alfalfa also has many benefits in regards to soil health. Alfalfa roots associate with rhizobia bacteria that convert atmospheric nitrogen gas into nitrogen fertilizer which can be deposited into the soil or boost the protein content of the plant (Doran, 2002). A key aspect to nitrogen fixation is ensuring the rhizobacteria in the soil is compatible to alfalfa. If the crop has not been grown in the region before, there may be incompatible rhizobia bacteria in the soil, preventing alfalfa from adding nitrogen to the soil. A solution to this would be to introduce the bacteria to the soil prior to the planting of the alfalfa such as by purchasing rhizobacteria-coated seeds (Martínez-Viveros, 2010). Alfalfa can be a useful tool in the prevention of land degradation, which has shown to be major issue in developing nations.

Critical Analysis

Alfalfa seed value is highly dependent on the type of variety and the traits it possesses. Varieties that have been bred to survive drought (such as Longzhong and Longdong) would be beneficial, however, such varieties will likely cost more in terms of seed. Drought tolerant varieties typically have longer root systems. The price of alfalfa seed generally ranges from $1 to $4 per pound, and it is recommended that pure alfalfa stands should be seeded at 12 to 16 pounds of seed per acre if it is planted conventionally; if the seed is broadcasted, it should be seeded at 14 to 20 pounds per acre (Undersander, 2011). Therefore, depending on the size of the field, alfalfa can have a large upfront cost, especially for subsistence farmers.

Depending on the soil pH, it may be very beneficial to apply lime to the field, especially if it is the first-time growing alfalfa in the area. Soil acidity can greatly affect alfalfa production and the ability for the plant to fix nitrogen; when the pH of a soil is 6.2 or lower, alfalfa plants tend to not grow as well (Undersander, 2011). Liming the soil raises the pH, and therefore, can increase alfalfa yield and stand quality. Bagged lime costs between $12-25 per acre, and there can be a large amount of labour associated with the application of the lime because it must be integrated into the soil below the A horizon in order to have the greatest effects (Smith, 2020).

Similar to agricultural lime, fertilizer can provide great benefits to the quality of an alfalfa stand. Fertilizer requirements are dependent on the soil and the nutrients that are available prior to the fertilizer. Nitrogen fertilizer is not required for alfalfa due to the nitrogen that it adds to the soil via microbial nitrogen fixation. However, newly seeded alfalfa may require some nitrogen fertilizer for its first year in soils that are composed of sand or have very little organic matter (Nebraska Institute of Agriculture and Natural Resources, 2020). The application of phosphorus and potassium are necessary in some soils for a well producing alfalfa stand. Fertilizer prices are highly dependent on the global price of natural gases, so fertilizer costs may vary year to year. Fertilizer that is high in potassium and phosphorus roughly costs $2.00 per lb, however, there are many factors that can alter the price of the fertilizer (Flynn, 2017).

Humidity has also been shown to create challenges in the growing and storage of alfalfa. During the growing period, high humidity for long periods can allow disease to flourish in the alfalfa stand. Diseases such as anthracnose, bacterial wilt, and root rot can greatly affect the success of the stand (Undersander, 2011). Furthermore, humidity such be considered when harvesting alfalfa to ensure good quality hay. Alfalfa should be baled at 13-16% moisture; hay baled with a higher moisture has a high probability of developing fungal mold, which will decrease its nutritional value (Undersander, 2011).

Links to Useful Resources

https://ciat.cgiar.org/ciat-projects/adapting-agriculture-to-climate-change-collecting-protecting-and-preparing-crop-wild-relatives/ - Seed Bank and Information regarding adapting agriculture to climate change

https://www.agronomy.org/files/publications/alfalfa-management-guide.pdf - Link to Alfalfa Management Guide

http://www.fao.org/land-water/databases-and-software/crop-information/alfalfa/en/ - Link to FAO info page on Alfalfa

https://www.youtube.com/watch?v=y9EBsD1BfXQ - YouTube video on how to start a good alfalfa stand from the University of Wisconsin

https://www.youtube.com/watch?v=bViTQWZ_QLQ - YouTube video on how to harvest alfalfa using scythe

https://www.hubbardfeeds.com/blog/preparing-alfalfa-harvest - Link to article on preparing for alfalfa harvest

https://aces.nmsu.edu/pubs/_circulars/CR668/welcome.html - Link to article on reducing harvest and post-harvest losses of alfalfa

References

1. FAO. (2020). Alfalfa. Food and Agricultural Organization of the United Nations. FAO, Rome. Retrieved from http://www.fao.org/land-water/databases-and-software/crop-information/alfalfa/en/

2. Bellague, D., M’Hammedi-Bouzina, M., & Abdelguerfi, A. (2016). Measuring the Performance of Perennial Alfalfa with Drought Tolerance Indices. Chilean Journal of Agricultural Research, 76(3), 273-284.

3. Brough, R. C., Robison, L. R., & Jackson, R. H. (1977). The Historical Diffusion of Alfalfa. Journal of Agronomic Education, 6(1), 13-19. Retrieved from https://www.agronomy.org/files/publications/nse/pdfs/jnr006/006-01-0013.pdf

4. Doran, J. W. (2002). Soil health and global sustainability: translating science into practice. Agriculture, Ecosystems & Environment, 88(2), 119-127. Retrieved from https://doi.org/10.1016/S0167-8809(01)00246-8

5. Flynn, R. (2017). Calculating Fertilizer Costs. New Mexico State University. Retrieved from https://aces.nmsu.edu/pubs/_a/A133/welcome.html

6. Food and Agriculture Organization of the United Nations (2012). Alfalfa Hay: Nutrient Analysis. Retrieved from https://www.feedipedia.org/node/11743

7. Foster, S., Nelson, D., & McCuin, G. (2009). Alfalfa for Beef Cows. University of Nevada, Reno. Retrieved from https://extension.unr.edu/publication.aspx?PubID=2228

8. Government of Western Australia: Agriculture and Food. (2019). To hold or sell breeding cattle. Retrieved from https://www.agric.wa.gov.au/dry-seasons and-drought/hold-or-sell-breeding-cattle

9. Martin, N. P., Mertens, D., Hatfield, R., & Jung, H. (2008). Alfalfa: Forage Crop of the Future. University of Kentucky, USA. Retrieved from https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1072&context=ky_alfalfa

10. Martínez-Viveros, O., Jorquera, M. A., Crowley, D. E., Gajardo, G. M. L. M., & Mora, M. L. (2010). Mechanisms and Practical Considerations Involved in Plant Growth Promotion by Rhizobacteria. Journal of Soil Science and Plant Nutrition, 10(3), 293-319. Retrieved from https://scielo.conicyt.cl/scielo.php?pid=S0718-95162010000100006&script=sci_arttext

11. Morton, J. (2007). The Impact of Climate Change on Smallholder and Subsistence Agriculture. U.S. National Academy of Sciences.104 (50), 19680-19685 Retrieved from https://www.pnas.org/content/104/50/19680

12. Mueller, S. (2005). Considerations for Successful Alfalfa Stand Establishment in the Central San Joaquin Valley. In Proceeding California Alfalfa and Forage Symposium (pp. 12-14). Retrieved from https://alfalfa.ucdavis.edu/+symposium/proceedings/2005/05-263.pdf

13. Shirani, H., Hajabbasi, M. A., Afyuni, M., & Hemmat, A. (2002). Effects of Farmyard Manure and Tillage Systems on Soil Physical Properties and Corn Yield in Central Iran. Soil and Tillage Research, 68(2), 101-108. Retrieved from https://doi.org/10.1016/S0167-1987(02)00110-1

14. Smith, D. (2020). Dial in Soil pH. The Indiana Aglime Council. Retrieved from https://aglime.org/resources/dial-in-soil-ph/

15. Sofi, J. A., Rattan, R. K., Wani, A. A., Mir, S. A., Dar, I. H., & Sofi, K. A. (2018). Nitrogen-Fixing Cover Crops and Chronosequential Effects on Fertility of Apple Orchard Soils. Agricultural Research, 7(1), 51-60. Retrieved from https://idp.springer.com/authorize/casa?redirect_uri=https://link.springer.com/article/10.1007/s40003-018-0290-1&casa_token=HGmVIB6nHF8AAAAA:4r2Bz0lyaPSKH2Svp_DXSO9KeZBA8rmrpuKhWdcAe0pmAkcb0Y7ONG2Spkbf4SCdgc_wEv-Icf7krWMfUQ

16. Soil Management to Optimize Alfalfa Production. Nebraska Institute of Agriculture and Natural Resources. (2019). Retrieved from https://cropwatch.unl.edu/forages/soils

17. Undersander, D., Cosgrove, D., Cullen, E., Grau, C. (2011). Alfalfa Management Guide. American Society of Agronomy. 3-54. Retrieved from https://www.agronomy.org/files/publications/alfalfa-management-guide.pdf