Chapters 5.31

5.31 -The Adoption of Proso Millet as a Staple Crop for Smallholder Farmers Challenged with Climate Change

Tobias Schwartz, University of Guelph, Canada

Suggested citation for this chapter.

Schwartz,T. (2022) The Adoption of Proso Millet as a Staple Crop for Smallholder Farmers Challenged with Climate Change, In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org

Background to Proso Millet

Proso millet, alternatively named common millet, is an important crop (like many other millets) for subsistence farmers in regions of Asia and Africa (Goron and Raizada, 2015), due to its high concentrations of essential nutrients, heat and drought stress tolerance, and short growing season (Johnson et al., 2019). As one of the oldest known cultivated cereals, following barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) (Johnson et al., 2019), proso millet was first domesticated in Neolithic China around 10,000 years ago, from where its use spread into Eurasia and later into North America around the 1700s (Goron and Raizada, 2015). While a confirmed ancestral species has yet to be determined, in situ research suggests that common ancestors could potentially be “witchgrass” (Panicum capillare) and “torpedo grass” (Panicum repens) (Habiyaremye et al., 2017). The majority of proso millet produced in North America goes towards the production of birdseed and animal feed, whereas it is consumed by humans as food in areas of India, Pakistan, South Eastern Asia, and many other countries (Goron and Raizada, 2015).

Proso millet can be categorized into five races based on its grain head (inflorescence) shape, which are known as miliaceum, contractum, ovatum, compactum, and patentissimum (Johnson et al., 2019). Contractum plants have hanging inflorescences, compactum plants have cylindrical inflorescences, ovatum plants have curved inflorescences, and both miliaceum plants and patentissimum plants have larger and more open inflorescences (Goron and Raizada, 2015). There are more than 29,000 accessions of proso millet kept in genebanks around the world (Vetriventhan et al., 2019), with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT, India) having a collection of 842 accessions of the five different races of proso millet, of which breeding programs exist (Goron and Raizada, 2015). The most substantial accumulation of proso millet, however, belongs to the N.I. Vavilov All-Russian Scientific Research Institute of Plant Industry (located in St. Petersburg), which, as of 2012, holds 8778 accessions (Goron and Raizada, 2015).

Nutrients

Proso millet is a good source of protein, carbohydrates, and minerals, with there being 12.5 g of protein and 70.4 g of carbohydrates per 100 g of proso millet (Habiyaremye et al., 2017). In addition to these macronutrients, there are 14.2 g of dietary fibre, 14 g of calcium, 3.1 g of fat, 206 mg of phosphorus, and 10 mg of iron per 100 g of proso millet (with significant sources of potassium, magnesium, and zinc as well). As for micronutrients, proso millet is rich in Vitamin B6, B-complex vitamins, niacin, and folic acid – the latter critical for pregnant women. It is also a good source of sulfur-containing amino acids, such as cysteine and methionine, as well as the other essential amino acids, excluding lysine and threonine, some of which are deficient in major cereals such as corn and wheat. Like many millets, proso millet does not contain gluten, which can be desirable for individuals with gluten allergies, but undesirable for use as flour in raised bread. When compared to other major species of cereals, such as maize, sorghum, and rice, proso millet has a greater concentration of fat (Habiyaremye et al., 2017).

Growth and Reproduction

As a short season, annual crop, proso millet grows very quickly, with plants reaching maturity around 60 to 90 days after planting (Sheahan, 2014). In addition to this, its drought tolerance and low water requirement (potentially the lowest of any cereal) allows proso millet to grow well in areas of dry, sandy soil and hot temperatures (Goron and Raizada, 2015). It also has high water use efficiency (WUE) and can yield useable grain with a mere 330 to 350 mm of rainfall per year (Goron and Raizada, 2015), while having shoots that reach 30 to 100 cm in height (Baltensperger, 2002). The grains of proso millet are, on average, 2 mm wide and 3 mm long, and usually appear white, yellow, or red, but can sometimes be brown, black, or gray, depending on the variety and environment (Habiyaremye et al., 2017). However, even when equipped with these desirable drought tolerant traits, proso millet grows best in mild temperature locations and areas of higher altitudes, such as plateaus or mountainous regions, with some crops growing at elevations of around 3500 m (Baltensperger, 2002). Proso millet can also grow well in more northern areas, in contrast to some other millets, with certain crops growing at latitudes as high as 54°N (Baltensperger, 2002). In terms of reproduction, proso millet is a tetraploid with 36 chromosomes (Johnson et al., 2019). It is categorized as a self-pollinating plant, but around 10% of crops undergo cross-pollination (Baltensperger, 2002). Proso millet is also a warm season crop, requiring higher seed germination temperatures (ideally around 20 to 30°C) and exhibiting higher sensitivity to frost (Habiyaremye et al., 2017). Proso millet is a C4 plant and can fix carbon at an efficient rate. As well, it has a low ratio of water transpiration, further adding to its WUE and allowing it to grow in environments of low nitrogen, CO2, and water. During its growing season, proso millet will halt vegetative growth (flowering, stem growth, etc.) when temperatures surpass 30°C. This helps to deal with drought conditions by increasing WUE. As for soil acidity, proso millet grows well in slightly acidic soils, with germination occurring at a pH between 5.5 and 6.5 (Habiyaremye et al., 2017).

Utilization of Proso Millet

The uses of proso millet vary extensively. Utilization of proso millet, traditionally, is divided into 4 main categories of cooking: grain, meal, flour, and drink (Sakamoto, 1987). The grain of proso millet can be boiled and eaten, made into gruel, or made into mochi. It can also be made into a meal, which is then used to make porridge. As for proso millet flour, foods include dumplings, flour porridge, and bread. Lastly, proso millet can also be used to make beverages, either alcoholic or non-alcoholic (Sakamoto, 1987). In addition to this, a common use of proso millet is as livestock feed and birdseed, the production of which are seen more in North America (Sheahan, 2014). Due to its nutrient composition, proso millet could be substituted for maize or sorghum as fodder for swine, cattle, and poultry (with lysine supplementation) (Sheahan, 2014). Proso millet is also a valuable rotational crop, improving wheat yields by mitigating grassy weeds, increasing soil nutrients and moisture, and by reducing pest and pathogen pressure (Habiyaremye et al., 2017). In addition to this, proso millet does well as a catch crop or as green manure for sorghum, maize, cowpea, and soybeans (Sheahan, 2014). Another use of proso millet that should be considered is its potential as a source of fuel through its conversion to ethanol, which, while less efficient than corn, could be beneficial to ethanol producers (Rose and Santra, 2013).

Marketing of Proso Millet

Prices of proso millet often fluctuate in the North American market, with prices often peaking in December and April (Baltensperger et al., 1995). Compared to the prices of sorghum and maize, proso millet prices have generally been higher. Marketing prices, however, will depend heavily on production costs and harvest yields, making price predictions highly specific to certain areas and facilities (Baltensperger et al., 1995). The commercialization of proso millet and other millets varies considerably between countries as well. In developing countries, trading is very common for smallholder farmers with limited access to large marketing outlets. For example, in Africa, 80% of the trading of millets is related to the brewing and processing of beverages, while the remaining 20% accounts for the production of porridges (Obilana, 2003). In order to raise the amount of income proso millet can provide, proper marketing programs are needed in developing countries to provide access to smallholder farmers looking to sell or buy proso millet (Obilana, 2003).

Planting Practices

As a short season, summer annual crop, proso millet grows best during the warmer seasons of the year and, since it matures very quickly, planting can be done at the beginning of spring (Shanahan et al., 1988). Due to its reliability, proso millet can act as a catch crop, allowing for harvest and income when other crops fail, especially due to increased temperatures and reduced water availability in arid regions due to climate change (Habiyaremye et al., 2017). Traditionally, proso millet is planted using a tillage system (Anderson, 1990). However, mechanically tilling soil into mounds can result in increased soil erosion from water and wind, and it is therefore suggested that a non-tillage system be used for the planting of proso millet (Anderson, 1990). When planting seeds, soil temperatures should be around 13 to 18°C, with germination occurring between 10 to 45°C (Sheahan, 2014). Proso millet seeds are commonly drilled into the soil (around ½ to ¾ inches in) at varying amounts per acre based on use: 30 to 40 lbs/acre for proso millet feed or forage and 20 lbs/acre for proso millet seed or grain. As for crop maintenance, proso millet does not require high levels of water or nutrient supplements, but fertilizers may be required, depending on soil tests. Potential pest issues may include thrips and grasshoppers feeding on the leaves or European corn borer moths laying eggs on the plants. Other organisms that may consume proso millet include pheasants, turkeys, bobwhite quail, mourning doves, and multiple species of songbirds. In terms of weed management, it is suggested that proso millet should not be rotated with other crops for more than 3 years to avoid weed build-up. When harvesting, proso millet crops can be disked or mowed, manually or mechanically. Some issues concerning proso millet that should be taken into consideration are the potential for lodging (plants falling over and grains rotting on the ground), high moisture content at harvest, and seed shattering, but labour is otherwise minimal (Sheahan, 2014).

Conclusion

When considering the advantages of introducing proso millet to mitigate climate change, it can be seen that there is potential. In the next 40 to 100 years, the global mean annual temperature is expected to rise by 1 to 5.8°C, with the highest increases being in the subtropical and tropical regions (Kotschi, 2006). As a result of this increase in temperature, water will evaporate from soils at an increased rate, pests and diseases will increase in incidence, and organic matter decomposition in soils will increase (Kotschi, 2006). Due to its low water and nutrient requirements, fast growth cycle, low labour requirements, high WUE, and high concentration of nutrients, proso millet is an excellent crop for smallholder farmers that should be given more attention as a solution to climate change issues.

Additional Information

https://agricultureandfoodsecurity.biomedcentral.com/articles/10.1186/s40066-018-0183-3 Article discussing the advantages of millets.

https://www.icrisat.org/farmers-turn-to-millets-as-a-climate-smart-crop/ Article discussing how the advantages of millets apply to farmers.

https://www.agmrc.org/commodities-products/grains-oilseeds/proso-millet Article discussing the marketing and production of proso millet, with links to statistics and production cost summaries.

https://www.icrisat.org/wp-content/uploads/2017/10/ICRISAT-Seed-system-booklet.pdf PDF from ICRISAT explaining seed systems and how smallholder farmers can access seeds.

https://www.greencoverseed.com/product/1043/ Website selling white proso millet seeds for $0.88 US per lb.

https://mbsseed.com/products/wildlife-seed/millets/white-proso-millet-50lb-bag.html Website selling 50 lb bags of white proso millet seeds for $36.00 US.

http://extensionpublications.unl.edu/assets/pdf/ec137.pdf Article from the University of Nebraska explaining the production and marketing steps of proso millet. https://www.extension.iastate.edu/alternativeag/cropproduction/pearlmillet.html Article from Iowa State University explaining the planting and management of proso millet.

https://www.youtube.com/watch?v=z_34f8e-YHM Video showing one method of planting proso millet.

https://www.youtube.com/watch?v=81zI0pE7uaM Simple video explaining how to plant and grow millets.

https://www.youtube.com/watch?v=GJV_J4XKfls Video showing how to cook millet.

https://www.youtube.com/watch?v=vLZLvVZxUK0 Video on how to make millet rice.

http://farmtotable.colostate.edu/prepare-resources/millet-recipes.pdf List of millet recipes with steps and nutritional information.

References

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2. Baltensperger, D. D. (2002). Progress with Proso, Pearl and Other Millets. Trends in New Crops and New Uses, eds J. Janick and A. Whipkey (Alexandria: ASHS Press), 100-103. a. https://hort.purdue.edu/newcrop/ncnu02/pdf/baltensperger.pdf

3. Baltensperger, D., Lyon, D., Anderson, R., Holman, T., Stymiest, C., Shanahan, J., Nelson, L., DeBoer, K., Hein, G., & Krall, J. (1995). Producing and Marketing Proso Millet in the High Plains. University of Nebraska Cooperative Extension Fact Sheet EC95-137-C. Retrieved from: https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1702&context=extensionhist

4. Goron, T. L., & Raizada, M. N. (2015). Genetic diversity and genomic resources available for the small millet crops to accelerate a New Green Revolution. Front. Plant Sci., 6: 157 a. https://www.frontiersin.org/articles/10.3389/fpls.2015.00157/full

5. Habiyaremye, C., Matanguihan, J. B., Gueudes, J. D., Ganjyal, G. M., Whiteman, M. R., Kidwell, K. K., & Murphy, K. M. (2017). Proso Millet (Panicum miliaceum L.) and Its Potential for Cultivation in the Pacific Northwest, U.S.: A Review. Front. Plant Sci., 7:1961. a. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5220228/.

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8. Obilana, A. B. (2003). Overview: Importance of Millets in Africa. ICRISAT. Nairobi, Kenya. Retrieved from: http://www.afripro.org.uk/papers/paper02Obilana.pdf

9. Rose, D. J., & Santra, D. K. (2013). Proso millet (Panicum miliaceum L.) fermentation for fuel ethanol production. Industrial Crops and Products, 43, 602-605. a. https://www.sciencedirect.com/science/article/pii/S0926669012004803

10. Sakamoto, S. (1987). Origin and Dispersal of Common Millet and Foxtail Millet. JARQ, 21(2), 84-89. a. https://pdfs.semanticscholar.org/0487/d8cd7d812b232a6345bf060865e567b47b1c.pdf

11. Shanahan, J. F., Anderson, R. L., & Greb, B. W. (1988). Productivity and Water Use of Proso Millet Grown under Three Crop Rotations in the Central Great Plains. Agron. J., 80(3), 487-492. a. https://dl.sciencesocieties.org/publications/aj/abstracts/80/3/AJ0800030487

12. Sheahan, C. M. (2014). Plant guide for proso millet (Panicum miliaceum). USDA – Natural Resources Conservation Service, Cape May Plant Materials Center. Cape May, NJ. Retrieved from: https://plants.usda.gov/plantguide/pdf/pg_pami2.pdf

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