Pearl Millet to Mitigate Climate Change
5.15 - Pearl Millet to Mitigate Climate Change
David Rether, University of Guelph, Canada
Suggested citation for this chapter.
Rether, D. (2022) Pearl Millet to Mitigate Climate Change. In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. farmpedia.org
Introduction
Climate change is gradually becoming a major production constraint on agriculture worldwide. Both commercial and subsistence farmers feel the struggles cast upon them by climate shifts; increasing temperatures are altering growing conditions, meaning farmers must continuously improvise and adapt. This chapter examines how pearl millet (Pennisetum glaucum) can be utilized by subsistence farmers in Africa and India to combat drought, ensuring that families can secure both food security and a reliable income source.
Crop Information & Growing Conditions
Origin and Distribution: The origin of pearl millet trace back to the tropical region of western Africa over 4,000 years ago (Myers, 1999). Pearl millet possesses 32 distinct landraces in total (Ragupathy, 2016). Some of the most well-known types of small millets include foxtail, common, and finger millet (Kajuna, 2001). Today, pearl millet is widely grown by subsistence farmers in West Africa and India, serving as both a staple food and a valuable forage or grain crop for poultry and cattle feed. In developed nations like the United States, it is also frequently processed into birdseed (Myers, 1999). International seedbanks, including those managed by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), preserve pearl millet germplasm in India, Kenya, Malawi, Zimbabwe, Mozambique, Ethiopia, Mali, Niger, and Nigeria. Pearl millet stands as the most widely grown millet in Africa and the fourth most important cereal crop cultivated in India (Kajuna, 2001).
Environmental Tolerances: Pearl millet is significantly more drought-tolerant than sorghum and thrives on sandy soils where other grains fail (Kajuna, 2001). It takes roughly 80 to 100 days to mature. Since many subsistence farmers lack irrigation systems, pearl millet's ability to produce viable yields with annual rainfalls as low as 150 mm is a massive advantage (NRC, 1996). However, unlike sorghum, pearl millet cannot enter a state of dormancy during dry spells. Because of this, precipitation must be relatively evenly distributed throughout its 100-day growing season—a severe drought during the flowering stage can cause the crop to fail completely (NRC, 1996).
Soil and Temperature Requirements: Pearl millet grows best in light, well-drained loamy soils. It does not perform well in heavy clays due to its low tolerance for waterlogging. It is highly tolerant of acidic soils (tolerating pH levels as low as 4.0 to 5.0) and soils with high aluminum concentration (NRC, 1996). To mature successfully, it demands high daytime temperatures, with daily highs exceeding 30 degrees Celsius. In low-input smallholder settings, typical grain yields average around 500 kg per hectare—roughly eight times lower than what is achieved under irrigated, high-input conditions (NRC, 1996). Despite lower average yields, farmers favor it because it germinates well in hot, crusted soils, tolerates wind-blown sand damage, resists downy mildew, and exhibits excellent native pest tolerance (NRC, 1996).
Plant Nutrition, By-Products, and Consumption
Nutritional Profile: Pearl millet is a highly nutritious grain for human consumption. Per 100 grams, pearl millet provides: 11.8 g of protein, 4.8 g of fat, 2.2 g of ash, 2.3 g of crude fiber, 67 g of carbohydrates, 363 kcal of energy, 42 mg of calcium, 11 mg of iron, 0.38 mg of thiamin, 0.21 mg of riboflavin, and 2.8 mg of niacin (FAO, 1995). Compared to other Sub-Sahelian millets, pearl millet offers the highest energy and protein levels, the second-highest fat and riboflavin content, and the second-highest iron levels (FAO, 1995). It also contains essential amino acids, including cysteine (1.8 mg/g), isoleucine (3.9 mg/g), leucine (9.5 mg/g), lysine (3.2 mg/g), methionine (1.8 mg/g), phenylalanine (4.1 mg/g), threonine (3.3 mg/g), tryptophan (1.4 mg/g), tyrosine (3.0 mg/g), and valine (4.9 mg/g) (NRC, 1996).
Human Consumption: Traditionally processed by women and children, the grain is utilized as whole, cracked, or ground flour to prepare porridge, couscous, flatbreads (such as roti, kisra, and gallettes), local beers, and traditional snacks (NRC, 1996).
By-Products: The crop yields approximately 80% stalk (stover) and 20% grain. The thick stalks serve as vital construction materials for housing and fencing, as well as household fuel (NRC, 1996). Furthermore, the stover is an excellent feed resource for ruminants like cattle, goats, and sheep, enhancing the overall resource efficiency of integrated smallholder crop-livestock systems (Gupta et al., 2015).
Subsistence Farming Operations
Pearl millet requires minimal specialized equipment, making it highly accessible for low-income farmers. The key management phases include:
- Land Preparation and Sowing (Pre-planting): Prepare ridges spaced 75 to 90 cm apart. Planting should occur immediately after receiving approximately 25 mm of rainfall to ensure proper soil moisture for germination. Good quality seeds will germinate within 5 days (FAO, 2018).
- Seeding Calibration (Sowing): Sow seeds at a rate of 4 kg per hectare. Plant seeds 2.5 cm deep, placing 5 seeds together in hills spaced every 40 cm along the ridges (FAO, 2018).
- Soil Fertility and Weed Management (Early Growth): If synthetic fertilizer is affordable, apply 200 kg of NPK per hectare immediately after seeding, followed by a top-dressing of 50 kg of urea per hectare (FAO, 2018). Alternatively, integrate organic nitrogen sources such as animal manure or nitrogen-fixing trees. Implement early weeding or intercropping to suppress weeds like goosegrass (Eleusine indica).
- Staged Harvesting (Harvesting): Because pearl millet heads mature unevenly, harvest the crop in stages to prevent grain shattering in the field. Cultivate the seed heads (ears) leaving approximately 2 cm of stalk attached using hand knives (Kajuna, 2001).
- Drying and Threshing (Post-Harvest Processing): Sun-dry the harvested heads on raised platforms or mats for several days. Once completely dry, thresh the grain by beating the heads with wooden clubs on mats, then clean the seeds of sand, dirt, and chaff (Kajuna, 2001). Cleaning typically takes about 1 hour per 100 kg bag.
- Storage and Marketing (Storage): Pack the cleaned grain into hessian or sisal bags of up to 100 kg. Store in a dry, well-ventilated structure or transport directly to local markets (Kajuna, 2001).
Critical Analysis of Adopting Pearl Millet
Opportunities: Pearl millet is uniquely suited for smallholder climate adaptation. It is cheap to establish, demands no special machinery, and high-quality seeds are easily sourced from international organizations like ICRISAT. It outpaces sorghum and other millets under intense heat and sandy conditions. Additionally, its high nutritional value combats malnutrition, while its dual-purpose nature (80% biomass as stover) provides structural materials, fuel, and critical livestock feed during dry seasons. Economic studies from ICRISAT indicate that pearl millet has lower production costs than sorghum and maize, making it highly cost-effective for resource-poor farmers (Tsusaka, 2015).
Challenges & Constraints: Despite its high resilience, pearl millet presents severe labor constraints. The tedious tasks of staged harvesting, manual transport, and physical threshing fall disproportionately on women and children. While mechanical threshers can alleviate this burden, they are rarely financially viable for subsistence farmers. Furthermore, its vulnerability to rainfall gaps during flowering and its lack of a drought-dormancy mechanism mean that poor rainfall distribution can collapse yields from a healthy 1,500 kg/ha down to a meager 150 kg/ha (NRC, 1996). Bird predation also remains a persistent pre-harvest challenge that requires constant field guarding.
Resources
A video tutorial on manual and mechanical pearl millet threshing demonstrates grain extraction techniques.
Consult the Agropedia Guide to Pearl Millet Harvesting for step-by-step post-harvest operations.
Read the South Africa Millet Production Guide for tips on planting dates and climate requirements.
Review the African Organic Agriculture Training Manual for detailed organic production systems and pest controls.
Access over 85 traditional pearl millet recipes on the Cookpad Recipe Directory.
Watch a short documentary on cooking traditional pearl millet porridge in an African village setting.
Examine the ICRISAT Socioeconomic Report on Crop Profitability Indices comparing sorghum, maize, and millet.
References
1. Burgarella, C., et al. (2018). A western Sahara centre of domestication inferred from pearl millet genomes. Nature Ecology & Evolution, 2(9), 1377-1380. Full Text PDF
2. FAO. (1995). Sorghum and Millets in Human Nutrition (No. 27). Food and Agriculture Organization of the United Nations, Rome.
3. FAO. (2018). Seed production and handling manual for community-based seed inspectors and producers. FAO, Rome. Full Text PDF
4. Food, F. M. (2017, June 17). Real Village Food / Cooking Pearl Millet - Horse Gram Recipe in My Village. Video Reference
5. Gupta, S. K., Ghouse, S., Atkari, D., & Blummel, M. (2015). Pearl millet with higher stover yield and better forage quality: Identification of new germplasm and cultivars. CGIAR / ILRI Research Brief. Repository Link
6. Kajuna, S. T. (2001). MILLET: Post-harvest Operations. INPhO Post-harvest Compendium. Food and Agriculture Organization of the United Nations, Rome. Full Text PDF
7. Myers, R. (1999). Pearl Millet: A New Grain Crop Option for Sandy Soils or Other Moisture Limited Conditions. Jefferson Agricultural Institute, Columbia, MO. Full Text PDF
8. National Research Council (NRC). (1996). Lost Crops of Africa: Volume I: Grains. National Academies Press, Washington, DC. CrossRef DOI
9. Ragupathy, S., et al. (2016). DNA barcoding of some traditional small millet landraces in India. 3 Biotech, 6(1), 33. Publisher Link
10. Tsusaka, T. W., et al. (2015). Sorghum and millet production in semi-arid subsistence economies. ICRISAT Socioeconomics Discussion Paper Series. Full Text PDF