What are millets?
Millets are small-seeded grasses, widely grown around the globe for their nutritional benefits since time immemorial. Millets can be classified as major, minor and pseudo cereals. Major millets are Sorghum (Jowar), Pearl millet (Bajra) and Finger millet (Ragi), minor millets consist of Barnyard millet, Proso millet, Kodo millet, Little millet and Foxtail millet and pseudo millets include Buckwheat and Amaranth. Being Excellent source of nutrients, they are also called “ nutri-cereals” and “Shri Anna”. Apart from their nutritional benefits, millets are highly resistant to biotic and abiotic stresses, primarily grown under arid and semi- arid regions of Asia, Africa, Europe and the United States. India is the largest producer of millets, accounting for 80 % of Asia’s production and 37.5 % of global millet production.
Understanding Millet-based Agroforestry
Millet-based agroforestry (MbAF) is a nature-positive farming system that combines the cultivation of millets with trees and/or livestocks in the same agricultural land (Figure 1). This approach includes planting of trees alongside millets, either in rows as windbreaker, or in intercropping systems. Combining trees with millets in the same piece of land offers multiple benefits, such as modifying microclimate by providing shade, fixing atmospheric nitrogen, improving soil fertility by nutrient pumping and adding leaf litter and also offers additional sources of income through timber, fruits, medicinal products, etc (Figure 2).
Components of MbAF
Trees: In Southern India, Trees like Mahogany, Melia, Teak, and Sandal are prominently used in MbAF. Grewia oppositifolia, Prosopis cineraria, Zizypus mauritiana and Melia azedarach are prevalent in Western Indian states. However, Willow and Poplar are used in North India in various MbAF models.
Millets: Sorghum, Finger millet, Foxtail millet, Pearl millet, Barnyard millet and Proso millet.
Livestock:
Northern India: Cow: Sahiwal, Gir, Tharparkar, Hariani, etc; Buffalo: Murrah, Nili-Ravi and Sheep, Goat and Poultry.
Southern India: Cow: Ongole, Krishna Valley, Amrit Mahal, Hallikar, Malnad Gidda, etc.; Buffalo: Jaffarabadi, Bargur, Pandharpuri and Sheep, Goat and Poultry.
Eastern India: Cow: Red Sindhi, Hariana; Buffalo:Murrah, Toda, Bhadawari and Sheep, Goat and Poultry.
Western India: Cow: Sahiwal, Gir, Red Sindhi, Tarparkar, Kankrej, Deoni, Dangi, etc; Buffalo: Mehsana, Kherigarh, Nagpuri, Surti and Sheep, Goat and Poultry.
Figure 1. Millet-based Agroforestry (Modified from Dinesha and Teli, 2023)
Characters of Selected Trees:
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- Multipurpose and short rotating: These selected trees should be fast growing and should provide shade and nutrients to millet crops in a relatively short period. Furthermore, they should also offer multiple benefits such as providing fodder, fruits, timber and medicinal benefits.
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- Nitrogen fixing: Selection of leguminous trees will be beneficial as they fix atmospheric nitrogen in the soil, enriching it with this essential nutrient for healthy millet growth without the need for additional fertilizers in marginal lands.
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- Sparse crown: Their sparse crown structure allows filtered sunlight to reach the millet crops beneath, promoting optimal photosynthesis while minimizing competition for light and space.
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- Deep rooted: In drought prone areas, deep root systems help to efficiently access water and nutrients from deeper soil layers (nutrient pumping), reducing competition with millet crops for resources and enhancing overall soil health and stability.
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- Drought hardy: These trees are well-adapted to withstand periods of drought, ensuring they can continue to provide benefits to millet crops even under challenging environmental conditions.
Successful Millet-based Agroforestry Models from Arid and Semi-arid Regions:
1. Khejri (Prosopis cineraria) + pearl millet
Benefits: Increased yield attributed to leaf litter and nitrogen fixation.
Region: Commonly found in arid and semi-arid regions, particularly in parts of India.
2. Acacia senegal + pearl millet
Benefits: Led to a 61% increase in pearl millet yield and additional fodder and gum production.
Region: Suitable for agroforestry systems in arid and semi-arid regions, including parts of Africa and India.
3. Hardwickia binata and Zizyphus mauritiana+ pearl millet
Benefits: Resulted in significantly higher pearl millet equivalent yield compared to sole cropping.
Region: Suitable for regions with dry and arid climates, such as parts of India and Africa.
4. Prosopis cineraria and Tecomella undulata + pearl millet
Benifits: Yield of pearl millet documented in different tree densities.
Region: Indigenous to arid and semi-arid regions of India and surrounding areas.
Case Studies:
Millets serve as fundamental crops in dry and semi-arid regions like Rajasthan, Gujarat, Maharashtra, Karnataka, and Andhra Pradesh. Sorghum, pearl millet, and finger millet are primary millets consumed by millions, and when combined with locally adaptable fast-growing trees, they provide a sustainable solution for food security, land preservation, and economic stability. Numerous studies have explored agroforestry systems centered around millets, such as Teak with sorghum in Karnataka, Melia dubia with finger millet in Andhra Pradesh, Karnataka, and Telangana, showing increased economic returns. Intercropping pearl millet with P. cineraria and Z.mauritiana in Haryana and Rajasthan, respectively, and finger millet with G.oppositifolia and Glyricidia in Uttarakhand and Karnataka, respectively, not only enhance yield but also promote significant carbon sequestration and nitrogen fixation. Tamarind based brown top millet cultivation is prevalent in the dryland tracts of southern India. Trees like P. ceneraria and A. exelsa, A. senegal, Hardwickia binata and Colophospermum mopane are widely cultivated with millet crops in Gujarat, Rajasthan, and Madhya Pradesh States. These trees are a boon to the arid and semi-arid regions, where they adapt to dry conditions and can be used as livestock fodder, a windbreak in the desert, and to improve nutritional security.
The Role of MbAF in Restoring Agroecology: MbAF improves microclimate and water table, fosters agricultural biodiversity, reduces erosion, and improves soil health, nitrogen and carbon, efficiently pumps water and nutrients at the time of scarcity (Figure 2). In Addition, MbAF effectively utilizes resources and maintains a relatively closed nutrient cycle, protects cattle and farmland from severe weather, lowers greenhouse gas (GHG) emissions while providing various kinds of ecosystem services.
Figure 2. Role of Millet-based Agroforestry in restoring agroecology (Modified from Dinesha and Teli, 2023)
The Economic and Ecological Role of Millet-based Agroforestry
A. Soil Health Management: Combining trees with millet cultivation in arid and semi-arid regions helps in soil stabilization, erosion control and nutrient retention due to their deep root systems, thereby improving soil health and fertility.
Example: The study conducted at ICAR-IISWC, Dehradun from 2009 to 2018 evaluated the role of millet based agroforestry (MbAF) systems in soil water conservation and biomass production. Intercropping of barnyard millet with Morus alba increased carbon stocks of 22.9 t ha−1 and produced the highest yield of green fodder and dry fuel wood. These systems also minimized soil loss and runoff compared to traditional cultivation practices. Furthermore, these systems improved soil physical properties and fertility status significantly.
B. Water Conservation: Agroforestry systems with millets reduce water usage by providing shade and moisture retention and runoff by their deep root system, promoting efficient water management in arid and semi-arid regions.
Example: Hedge row planting of Gliricidia with finger millet reduced runoff of water by 29%, soil loss by 45-48% and increased soil moisture by 11-29%.
C. Biodiversity Enhancement: Integrating trees with millet cultivation fosters biodiversity by providing habitat for beneficial insects, birds, and microorganisms, contributing to ecosystem stability. Some trees are involved in effective control of insects by increasing insectivorous species and some trees also act as refugees to insects.
Example: The study conducted in sub-Saharan Africa showed that the millet head miner (MHM), Heliocheilus albipunctella, a major constraint to millet crop productivity. In MbAFS, Soapberry trees and neems indirectly supported the natural regulation of the MHM by offering shelters to insectivorous vertebrates, while baobabs had a direct impact by potentially providing refuge to MHM moths.
D. Livelihood Diversification: Millet-based agroforestry offers additional sources of income through the sale of timber, fruits, nuts, and fodder, enhancing rural livelihoods and socio-economic resilience.
Example: Some studies reported that the MbAF system increased two- or three-fold higher income than income earned from a sole crop. For instance, finger millet-based M. dubia showed a B:C ratio of 18.64, finger millet with bamboo resulted 3.99:1 (Handa et al. 2019) and higher B:C ratio (2.54:1) was also seen in pearl millet-based poplar AFS. Hence, MbAF is a viable option to fulfill government ambition of doubling and diversifying farmers income.
E. Food and Nutritional Security: Millets are highly nutritious grains rich in protein, fiber, vitamins, and minerals, contributing to food security and improved nutrition for communities. These are considered as ‘superfoods’ as they are rich in macro and micronutrients such as high calcium in finger millet (364.0mg/100g), magnesium in foxtail millet (153.0mg/100g), iron in pearl millet (6.4mg/100g), phosphorus in sorghum (222.0mg/100g), fibers in foxtail millet (13.6g/100g), and protein (12.5g/100mg) in proso millet (Kadapa et al. 2023). Finger millet ball and sprouted powder is most preferred by diabetic patients as it is a rich source of Calcium, low glycemic index, and high dietary fiber. Hence, including millets in under-utilized fruit trees in marginal lands not only increase food security but also nutritional security as trees are also a rich source of nutrients, vitamins and protein.
Example: Research in Africa showed that millet based Faidherbia albida system increased 2.5 and 3.4 grain and protein production, respectively. The pods of F.albida possess crude protein of 20.63% and carbohydrate of 40.1% in seeds, and are eaten by animals.
F. Climate Adaptation: Evolutionary innovations of millets that support resilience includes C4 photosynthesis with Kranz anatomy, altered stomata, salt glands, desiccation tolerance, high water use efficiency, improved leaf water potential and deep root systems (Gaff and Oliver 2013). Millets have a less carbon (C) footprint, lower water requirement, and a shorter life cycle compared to the other crops. They also produce enough output even in times of monsoon failure, increased temperature, and rising CO2 levels. Therefore, integration of climate resilient crops with trees is well-suited to erratic rainfall patterns and harsh growing conditions, providing farmers with a sustainable adaptation strategy in the face of climate variability.
G. Cultural Heritage: Millets have deep cultural significance in many regions, and their integration into agroforestry systems preserves traditional farming practices and indigenous knowledge.
H. Insect control: The trees used in MbAF can have direct or indirect effect on insect control either by increasing insectivorous insects or directly refusing insects. Hence, they can reduce insect infestation in millets.
Example: The flowers of P. reticulatum have a repulsive effect on the flower beetles, which helped in keeping pests away and producing higher yield of millet in the field with P. reticulatum.
Challenges of MbAF:
Competition for Resources: Trees and millet crops may compete for resources such as water, nutrients, and sunlight, impacting the growth and yield of both.
Insect, Pest and Disease Management: Certain pests and diseases can affect millet crops and trees differently, requiring careful management strategies to prevent losses.
Example: Baobab trees can reduce millet yield by harboring disease-carrying insects, exacerbating production challenges in agroforestry systems
Microclimate Effects: Trees in agroforestry systems can modify the microclimate, affecting factors like temperature, humidity, and wind speed, which may not always be favorable for millet growth.
Example: The productivity of pearl millet and cluster beans grown under five-year-old A. indica decreased because of the shading effect and bird damage caused by a dense tree canopy.
Harvesting and Processing: Harvesting and processing millet in agroforestry systems with trees can be more labor-intensive and challenging due to the presence of trees and their roots.
Market Access and Value Chains: Integrating millet with trees in agroforestry may affect market access and value chains differently compared to monoculture systems, requiring adjustments in marketing and distribution strategies.
Incompatible Tree-Crop Combinations: Some tree-crop combinations compete for nutrients, water, and light, leading to reduced productivity and yield in agroforestry systems.
Traditional Farming Practices: Reliance on subsistence farming using age-old practices may limit productivity and resilience to external challenges in production.
Addressing these challenges requires careful planning, monitoring, and adaptation of agroforestry practices to suit local conditions and needs.
In summary, MbAF acts as a holistic approach to sustainable agriculture, balancing ecological integrity with socioeconomic development. By tapping the complementary relationships between millet crops and trees, this system holds the potential to enhance food and nutritional security, soil and environmental conservation, and income diversification and rural livelihoods in resource constrained and environmentally stressed regions. MbAF represents a viable solution towards building resilient and remunerative agricultural systems capable of meeting the challenges of climate change and food insecurity.
For further reading:
Dinesha, S., & Teli, S. B. (2023). Millet-based agroforestry: a nature-positive farming to achieve climate-resilience and food security in India and Africa. Available at SSRN: https://ssrn.com/abstract=4461034 or http://dx.doi.org/10.2139/ssrn.4461034
Gaff, D. F., & Oliver, M. (2013). The evolution of desiccation tolerance in angiosperm plants: a rare yet common phenomenon. Functional Plant Biology, 40(4), 315-328.
Handa, A. K., Dev, I., Rizvi, R. H., Kumar, N., Ram, A., Kumar, D., … & Rizvi, J. (2019). Successful agroforestry models for different agro-ecological regions in India. Central Agroforestry Research Institute (CAFRI), Jhansi and South Asia Regional Programme of World Agroforestry (ICRAF), New Delhi, 203.
Kadapa, S., Gunturi, A., Gundreddy, R., Kalwala, S. R., & Mogallapu, U. B. (2023). Agronomic Biofortification of Millets: New Way to Alleviate Malnutrition. In Millets-Rediscover Ancient Grains. IntechOpen.
