Indian Agriculture should Care about Rainfall Variability

Nitin Bassi

A recent article in the editorial page of Time of India (ToI), dated 30th June 2021, citing a study by IMD, warned of a decreasing south-west monsoon in eastern India and its likely impact on agriculture in that region. The article suggested the need for pricing of electricity supplied to farms and for promotion of micro-irrigation (MI) systems that use water more efficiently. An analysis of a 30 year rainfall undertaken by IMD was referred to in the article. It also called for the need to increase public investments in surface irrigation projects to arrest groundwater over-abstraction.

There has been a lot of research in India that looked at the scope for water saving through the establishment of water entitlements (quota), metering of farm wells, introduction of pro-rata pricing for farm electricity, and adoption of MI technology. There are conditions under which such interventions make difference in terms of water saving.

However, first, it is important to understand the regional variation in water endowments and the agricultural situation in our country. While most of the western (Gujarat, Rajasthan), north-western (Haryana, Punjab), and southern plateau region are naturally water scarce, the eastern region consisting of the Gangetic plains region of Bihar, Uttar Pradesh, and West Bengal, and plains of coastal Odisha are rich in water endowment. The difference in the average annual rainfall between the naturally water scarce and rich regions is atleast 1000 mm.

Further, the per capita availability of arable land is substantially higher in western and north-western India in comparison to the eastern parts. When there are physical limits to accessing groundwater, farmers in the naturally water scarce regions are found to be adopting crops that yield high returns per every unit of water. Therefore, they go for a diverse cropping pattern that consists of cash crops such as oilseeds, spices, fruits, and vegetables as well as food grains. Due to water scarcity, they mine water from the deep aquifers. However, in water rich eastern India, mainly paddy is grown under both under rainfed (with supplementary irrigation) and irrigated (winter and summer paddy) conditions. The groundwater in eastern India is bountiful (Gangetic alluvial plains) with shallow water tables. While high rainfall ensures that the water requirement of monsoon paddy is met from the soil moisture, groundwater used for irrigating winter and summer paddy is available from rainfall recharge and to an extent return flows from surface irrigation. However, not all farmers in eastern Indian have the resources to invest in wells and pump sets.        

Thus, regulating groundwater abstraction through metering and pro rata pricing of electricity and restricting access to energy should receive priority in western and north-western regions that also experience groundwater overdraft. While in the groundwater-abundant eastern regions of India, metering should be undertaken but the pricing structure in the farming sector should be designed in such a way that it encourages greater use of groundwater. Further targeted subsidies can be provided to small and marginal farmers in eastern India who do not have access to groundwater.  

Second, it is important to identify crops that are amenable to drip and sprinkler systems. While sprinklers are mostly used for the field crops such as cereals, drips are amenable to row crops such as groundnut, castor and cotton, and several fruits and vegetables. Paddy is not the choice for any of these technologies. Therefore, western India with a diverse cropping pattern is more suited for the introduction of MI systems, whereas it can only happen in eastern India if there is a major shift in cropping pattern towards the oilseeds and horticultural crops.

However, as pointed out by Kumar et al. (2008), the extent of water saving depends on five important factors: the MI technology used; the crop; the soil; the climate; and the groundwater environment. The potential for real water saving through the use of MI technology will be significant for row crops irrigated with drips, under arid or semi-arid climatic conditions when the water table is deep. The naturally water scarce regions meet these conditions. Hence, the adoption of drip will be more beneficial in such typologies rather than in water abundant eastern India.

Nevertheless, the article in ToI rightly pointed out the need for increasing public investments in surface irrigation projects. Along with the direct irrigation benefits, the canals provide many indirect benefits such as the groundwater recharge through seepage and irrigation return flows from the canal command areas, reduced pumping hours on account of the decrease in depth to groundwater levels, and availability of water for domestic and environmental requirements. The need to strengthen the canal network is more in water scarce regions where such benefits will be higher. Sardar Sarovar Narmada Project (SSNP) is one such recent example that has been able to provide several of the direct and indirect benefits to the water scarce areas in north Gujarat and Saurashtra. 

India already experiences a high spatial variability in rainfall and the water resources endowments. It also experiences high temporal variability, especially in the low to medium rainfall regions. At the aggregate level, it does not matter whether the rainfall decreases by 10-20 mm in a region which otherwise receives an average annual rainfall of about 1500 mm or so over a 30-year period. However, important is to accept the variability in climate and rainfall conditions and design region specific interventions that can lead to efficient use of water and an increase in agricultural productivity.

References

Kumar, M. D., Turral, H., Sharma, B., Amarasinghe, U., & Singh, O. P. (2008). Water saving and yield enhancing micro-irrigation technologies in India: When and where can they become best bet technologies? In M. D. Kumar (Ed.), Proceedings of the 7th Annual Partners Meet ‘Managing water in the face of growing scarcity, inequity and declining returns: Exploring fresh approaches, volume I’ (pp. 1–36). IWMI-Tata Water Policy Research Program, Hyderabad, India.

Nitin Bassi is Principal Researcher with the Institute for Resource Analysis and Policy (IRAP). Views expressed in this article are personal.

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