Crop production is highly influenced by the sensitivity of crops to variations in climate and can have major implications for food supply and rural livelihoods. The effects of climate change are increasing in India, where extreme rainfall events have become more frequent and spatially more variable. On the other hand, there has also been an increase in the severity and frequency of droughts.
This unpredictability and uneven distribution of rainfall and rising temperatures are feared to adversely impact the yields of major crops in the country. Thus, devising measures to buffer crop production against these stresses are a critical aspect of climate change adaptation in India.
India’s cropping systems dominated by rice and wheat
Rice is mainly grown during the monsoon (kharif) season and wheat during the winter (rabi) season, in the rice-wheat dominated cropping system in India.
The share of grain production contributed by rice and wheat has continued to grow, from 65% in the year 1966 to 85% in the year 2011. Rice accounts for 44% of annual grain production and 73% of grain production during the monsoon (kharif) season while maize, pearl millet, sorghum and ﬁnger millet often referred to as alternative grains/coarse grains/millets contribute the remaining portions of monsoon grain production (Davis et al, 2019).
Will climate variability pose a threat to crops and threaten food supplies in the long run?
The study titled ‘Sensitivity of grain yields to historical climate variability in India’ published in the journal Environmental Research Letters explores the susceptibility of the current mix and distribution of crops to variations in temperature and rainfall.
The study analyses the impact of historical rainfall and temperature variability on the yields of the ﬁve major rainfed grains produced during the monsoon (kharif) season namely, ﬁnger millet, maize, pearl millet, rice, and sorghum, and the beneﬁts of coarse grains over rice in coping with the impacts of climate change on crops.
The study reveals some interesting findings:
Rainfed yields of rice are significantly higher than alternative grain yields
Generally, rainfed yields of alternative grains such as ﬁnger millet, pearl millet, and sorghum are substantially lower than rice, while those for maize and rice are nearly identical. However, for certain districts and crops, the rainfed yields of alternative grains exceed those of rice, especially for pearl millet and sorghum in central India and maize in many parts of the country. This could be an opportunity to increase yields of alternative grains in these regions.
Alternative crops are less affected by rainfall related changes
The study finds that rice yields are much more sensitive to fluctuations in monsoon rainfall on both irrigated and rainfed croplands as compared to all other alternative grains. Among the alternative grains, only pearl millet shows some sensitivity to ﬂuctuations in rainfall.
Even during an extremely dry year, rainfed alternative grain yields are less affected as compared to rice, which shows significant yield reduction. This basically demonstrates that alternative grains are more resilient to changes in rainfall, than rice and wheat. Thus, allocating more croplands to alternative grains can help stabilise grain production across a range of climatic conditions.
Alternative grains can act as great buffers against increasingly frequent climate extremes, especially considering that half of kharif grain production is rainfed. The ﬁndings also suggest that irrigation plays only a limited role in buffering rice yields against increased rainfall variation.
All grains are sensitive to temperature related changes, but rice is worse off
In an extremely hot year, rainfed pearl millet yield is worse than rice while maize and ﬁnger millet yields are better as compared rice. Sorghum yields are similar to rice in extreme heat conditions.
Thus, almost all rainfed grain yields, with the exception of ﬁnger millet are sensitive to variations in monsoon temperatures.All grains could be impacted by an increasingly variable climate, but the degrees to which different grains are impacted differ quite a bit, with rice being the most impacted.
Selectively increasing coarse grains in crop production
The paper argues that while rice continues to be the most vulnerable to the impacts of variable rainfall patterns and temperature changes, increasing coarse grains in crop production can greatly help in developing resilience to climate change in the long run and improving crop production.
This can also be combined with other strategies to enhance the resilience of grain supply against climate shocks such as including buffer reserves, improving access to and utilisation of irrigation and more research to develop high-yielding drought-tolerant varieties of dominant crops.
Also, since the yields of rice continue to be high in the current circumstances, introduction of course grains to tackle climate change scenarios would mean that efforts would be needed to improve their yields while retaining their resilience to climate shocks. Thus more efforts and research with focus on yield improvements in alternative grains that do not compromise their climate resilience will be needed.
Besides building climate resilience, increasing alternative grain production would also provide other environmental and nutritional beneﬁts such as reduced agricultural water demand, greenhouse gas emissions, and energy use while providing solutions to micronutrient deﬁciency diseases such as anaemia. It can also provide an opportunity to reduce trade-offs between efﬁcient land use (i.e. yields) and high nutrient content for alternative grains through increased research.
A copy of the paper can be downloaded from below: