Climate-Resilient Jowar: A Viable Alternative To Wheat In India Under A Changing Climate

India's wheat production is at risk due to rising temperatures, prompting researchers to explore sorghum as an alternative cereal for the rabi season. A new study examines the sensitivity of wheat and sorghum yields to temperature changes, highlighting wheat's vulnerability and sorghum's resilience. The water requirements and footprints of the two crops are also compared. Promoting sorghum cultivation can provide a climate-resilient option for Indian agriculture, ensuring food security and efficient land utilisation in a changing climate. Policymakers should focus on diversifying crops, improving management practises, and expanding the market for sorghum.

India, the world's second-largest wheat producer, faces increasing concerns about the crop's sensitivity to rising temperatures. As a potential solution, researchers are exploring the viability of Jowar (sorghum) as an alternative cereal for the rabi season.

In this piece, I report on the sensitivity of wheat and sorghum yields to historical temperature changes, compare their water requirements, and discuss the implications for future climate projections. This is based on a new paper in Nature’s Journal Scientific Report. Along with the team of researchers, the paper titled - Climate Resilience of dry season cereals in India makes an interesting observation to bring in new science. Professor Ruth DeFries of Columbia University and Professor Ashwini Chhatre of the Indian School of Business led the report that discusses important policy options for supporting Jowar under rapidly changing climatic conditions in India.  

India has steadily increased wheat production since the Green Revolution, driven by yield and area expansion. In contrast, rabi sorghum production has declined despite increased yields due to a decreased cultivated area. The research study has examined the relationship between temperature and cereal yields in India, shedding light on the vulnerability of wheat crops to increasing temperatures during the rabi season.

The findings reveal a significant negative correlation between wheat yields and maximum daily temperatures, particularly during stage two and stage three of the growth period. With every one-degree celsius rise in temperature, there is a corresponding decrease in wheat yield, amounting to approximately a 3-4% reduction. Surprisingly, precipitation did not significantly impact wheat yields, given the reliance on irrigation or residual moisture. Climate models project an upward trend in maximum daily temperatures during the rabi season, with potential yield reductions of 2.4% to 10.3% for wheat by 2048–52. These projections, however, do not consider factors like improved varieties, management practises, and atmospheric carbon dioxide effects, which can influence yields.

Conversely, Sorghum shows a more marginal association with temperature, influenced by precipitation and radiation. The study found a positive correlation between sorghum yields and temperature, indicating that higher temperatures, accompanied by less precipitation and increased radiation, contribute to increased sorghum production during the early growth stage. However, the study also highlighted the influence of soil characteristics on sorghum yields, with less productive soils leading to lower yields.

These findings underline wheat's temperature sensitivity and sorghum's potential resilience in the face of climate change. As India experiences rising temperatures and shifts in precipitation patterns, it is crucial to adopt climate-resilient strategies in agriculture. Promoting the cultivation of cereals like sorghum, which has shown lower sensitivity to temperature, could provide a viable alternative to wheat in semi-arid regions.

As global temperatures rise due to climate change, sustaining crop productivity becomes a significant challenge for the agricultural sector. Among the various effects of increased maximum daily temperatures during the growing season, wheat yields are particularly affected. However, sorghum, an alternative crop, displays remarkable resilience to these temperature changes, offering hope for a sustainable future. Moreover, these crops' water requirements and footprints are crucial to their adaptability to climate change.

Wheat, a staple crop in many regions, is sensitive to elevated temperatures at different stages of its growth cycle. The reproductive phase is especially vulnerable, with high temperatures leading to reduced pollen viability and affecting fertilisation and grain development. Heat stress during grain-filling stages can cause smaller grain size and weight, resulting in lower yields. These temperature-induced challenges significantly threaten wheat production, necessitating immediate adaptation measures.

In stark contrast, sorghum demonstrates greater tolerance to increased maximum daily temperatures. Its physiological and anatomical characteristics enable better adaptation, such as smaller leaves that reduce heat absorption and transpiration rates. Furthermore, sorghum is more likely to maintain photosynthetic activity even under heat-stress conditions. These traits position sorghum as a promising alternative for cultivation in regions where temperature fluctuations pose a substantial risk to wheat production.

Water requirements and footprints also contribute to the divergent adaptability of these crops. Wheat's longer growing season, extending into the summer, demands 1.4 times more water than sorghum. However, wheat's higher yields compensate for its increased water requirements, resulting in approximately 15% lower water footprints than sorghum. Balancing water consumption and crop productivity becomes crucial when selecting suitable crops for a changing climate.

Future climate projections indicate a potential 5% decline in wheat yields by 2040 and a 12% increase in water footprints. In contrast, sorghum is projected to experience only a modest 4% increase in its water footprint. These findings underline sorghum's potential for expansion in the rabi season, showcasing its greater resilience to climate change-induced challenges. To fully harness the potential of sorghum as a climate-resilient crop, focused efforts are needed to enhance its yields. Research and development initiatives should concentrate on breeding high-yielding sorghum varieties with improved agronomic traits and stress tolerance. Additionally, providing farmers with training and access to improved cultivation practises will ensure profitability and efficient land utilisation.

The adverse impact of increased maximum daily temperatures on wheat yields throughout the growing season calls for adaptive strategies in agriculture. Sorghum emerges as a viable alternative, demonstrating resilience to temperature changes and a smaller water footprint. By promoting sorghum cultivation in regions vulnerable to rising temperatures, stakeholders can enhance the adaptability and profitability of agricultural systems while mitigating the potential impacts of climate change on food security. The resilience of sorghum serves as a beacon of hope for a sustainable and flourishing future amidst a changing climate.

India's thriving cereal production during the rabi season and the expansion of wheat cultivation into hotter regions necessitate adopting climate-resilient strategies for these crops. Policymakers must take action to safeguard the agricultural sector against climate change impacts. Here are three key policy prescriptions to address this pressing issue:

First, to ensure the long-term sustainability of cereal production in the rabi season, it is imperative to promote climate-resilient strategies. The government should actively encourage farmers to diversify their crops, emphasising millet due to its nutritional value and resilience to changing climatic conditions. Additionally, preserving and expanding rabi sorghum cultivation in semi-arid regions is vital, as it offers food security for small and marginal farmers in these vulnerable areas.

Second, enhancing agricultural productivity requires improving management practises and utilising high-yielding varieties. Farmers should have the knowledge and resources to implement optimised planting techniques and other measures that increase yields. For wheat farmers, adjusting the growing season to minimise exposure to extreme heat waves and adopting drought-resistant varieties can mitigate the adverse effects of rising temperatures. Similarly, emphasising sorghum cultivation on soils with high water holding capacity can improve yields.

Third, expanding sorghum’s acceptance and market reach is crucial to promoting its cultivation as a viable alternative to wheat. While sorghum is deeply rooted in the culture of sorghum-growing regions, its wider acceptance among consumers can unlock new opportunities for farmers. Highlighting the nutritional benefits, temperature resilience, and lower water requirements of sorghum through targeted marketing campaigns and awareness programmes will foster its adoption and boost farmer profits.

By implementing these, India can build climate resilience in its rabi cereal production. These measures not only enhance food security and mitigate the vulnerability of crops to rising temperatures but also pave the way for a sustainable and prosperous agricultural sector. Policymakers, farmers, and stakeholders must collaborate and prioritise climate-smart agricultural practises for a resilient and secure future.

Anjal Prakash is the associate professor (research) and research director at the Bharti Institute of Public Policy at the Indian School of Business. He contributes to IPCC reports.

The views expressed here are those of the author and do not necessarily represent the views of BQ Prime or its editorial team.