Since the last few decades, the central government (and also multiple states) has been promoting micro irrigation (drip and sprinkler) under various schemes. These schemes mainly include National Mission on Micro Irrigation (NMMI), On Farm Water Management (OFWM), and now Pradhan Mantri Krishi Sinchayee Yojana (PMKSY). The Per Drop More Crop (PDMC), emphasising micro irrigation, is one of the four components of PMKSY (GoI, n.a.).
In these policies, micro irrigation improving on-farm water use efficiency is framed as a water saving and conserving technology. The implicit expectation (of policy makers) in promoting micro irrigation is—since irrigation uses the largest share of water globally and in India, the saved water can be released to other competing users (other deprived farmers) and sectors with increasing water demand (e.g. urban, industry, and energy). Perceiving micro irrigation as water saving technology, the operational guidelines of PDMC also emphasise on prioritising water stressed and critical groundwater blocks/ districts of the country to address water scarcity (GoI, 2021).
However, this article explains that adopting micro irrigation does not automatically lead to water saving unless other required conditions are fulfilled. Otherwise, micro irrigation can accelerate the depletion of aquifers, drying of rivers, and disappearance of lakes and wetlands.
The scale of quantifying water saving matters
For on-farm water application, micro irrigation is promoted to save water which would have otherwise been lost in flood irrigation practice. Micro irrigation saves water at the farm scale. However, the same amount of water saving may not realise at the aquifer or river basin scale.
The quantification of water saving is specific to the scale of measurement. At the farm scale, the part of the water applied that is not used by the crop is considered as ‘waste’ or ‘loss’. Following this logic, flood irrigation is labelled as a water inefficient system. However, part of this wasted water percolates and recharges the aquifer or contributes to downstream river flows—referred as agricultural return flow. This agricultural return flow is reused by other water users of the basin (or aquifer), including environment, for other productive purposes. Thus, at the aquifer or river basin scale, this wasted water is actually a gain.
After implementing micro irrigation, the agricultural return flow reduces substantially and affects dependent water users. Thus, though the water saving is achieved at the farm scale with micro irrigation, these savings may not realise at the river basin or aquifer scale as agricultural return flows are no longer available in the same quantity.
Conversely, with flood irrigation, though on farm irrigation efficiency is low, after accounting for the agricultural return flows (made available through flood irrigation), facilitating water reuse can increase overall water use efficiency at the basin or aquifer scale. Therefore, while discussing water saving associated with micro irrigation, the scale of measurement matters (van Halsema & Vincent, 2012).
The saving from the micro irrigation is real saving only if the underlying aquifer is saline or downstream river flows are directly going to sea, where reuse of water is not feasible. However, for arriving at such a conclusion, complete water accounting of the aquifer or basin is essential.
Increase in the area under irrigation and cropping intensity
Evidence suggests farmers do not reduce water consumption after adopting micro irrigation. Therefore, there is no saved water that can be put to other use to relieve the water stress of existing sources (e.g. aquifer).
For example, after completion of eight years, the Ministry of Agriculture, Government of India commissioned a study to evaluate the impact of the National Mission of Micro Irrigation (NMMI). The study covered 7400 sampled beneficiary and non-beneficiary farmers spread across 64 districts in 13 states of India (Global AgriSystem, 2014).
The study claimed total seven impacts of the NMMI. Out of these seven, the first reported impact of NMMI is an increase in irrigation area from the same water source due to water saving. It found that the beneficiary farmers have brought an average of 8.4% of additional land under irrigation due to on-farm water saving from micro irrigation. This percentage is the highest for the state of Maharashtra (22.3%). So even after the introduction of micro irrigation, farmers were consuming the same quantities of water from aquifer and surface water based irrigation schemes.
Additionally, keeping the same water consumption levels and increasing the area under irrigation by beneficiary farmers reduces agricultural return flow, as drip and sprinkler reduce the quantities of percolated water, ‘wasted’ at the farm scale. This reduces downstream water flows, otherwise used by other water users. This approach results in the reallocation of water in the basin—meaning after the adoption of micro irrigation, farmers use water that other downstream water users were using earlier (van der Kooij, Zwarteveen, Boesveld, & Kuper, 2013). Thus by supporting farmers to adopt micro irrigation by providing subsidies under PMKSY, we are depriving downstream water users (including environment).
Need regulation of water use
The use of micro irrigation technology does not automatically result in a reduction in water consumption. As long as more water is available, farmers tend to use more water. For saving water and ensuring sustainable use, regulating water use and controlling water allocations are essential. After the introduction of micro irrigation, the water allocations of beneficiary farmers need to be reduced in proportion to ensure real water saving. The saved water can then be allotted to other water users to address the water stress situation. Otherwise, farmers tend to draw more water from the deeper aquifers.
Therefore, introducing water regulation and allocation mechanism is a prerequisite for achieving water saving through micro irrigation technology. Otherwise, micro irrigation reduces the downstream return flow and can exacerbate the water stress. Thus, promoting micro irrigation in the water stressed regions and groundwater over-exploited blocks/ districts defeats its purpose of relieving water stress. First, it does not reduce the water consumption of farmers, and second, by reducing return flows, micro irrigation can accelerate the depletion of aquifers and drying of rivers in the region.
Thus, though micro irrigation improves water use efficiency at the farm scale, reduces energy requirement, and reduces the application of fertiliser and labour costs; it does not automatically lead to water saving. Improving water use efficiency by adopting micro irrigation at the farm scale does not inform anything about water saving at river basin, region, or national scale. For achieving real water saving through micro irrigation, a mechanism for water regulation and allocation is essential to avoid the reallocation of water in the basin or aquifer.
Therefore, the Food and Agriculture Organisation (FAO) has also recommended that governments and donor agencies should follow the sequence of policy intervention described above and avoid funding micro irrigation programs in the absence of water control and allocation mechanism (Perry, Steduto, & Karajeh, 2017). However, in the context of India, regulating groundwater and surface water sources is another challenge in itself.
Author
Sachin Tiwale is an Assistant Professor at the Centre for Water Policy and Governance, School of Habitat Studies, Tata Institute of Social Sciences. He can be contacted at sachin.tiwale@gmail.com
The views expressed in this article are author’s personal views, and are not to be taken as the views of India Water Portal.
References
Global AgriSystem. (2014). National Mission on Micro Irrigation (MMI): Impact Evaluation Study.
GoI. (2021). Operational Guidelines of Per Drop More Crop Component of Pradhan Mantri Krishi Sinchayee Yojana: Ministry of Agriculture & Farmers Welfare, Government of India.
GoI. (n.a.). Pradhan Mantri Krishi Sinchayee Yojana. Retrieved from https://pmksy.gov.in/default.aspx
Perry, C., Steduto, P., & Karajeh, F. (2017). Does improved irrigation technology save water?: A review of the evidence. Cairo: Food and Agricultural Organization of the United States.
van der Kooij, S., Zwarteveen, M., Boesveld, H., & Kuper, M. (2013). The efficiency of drip irrigation unpacked. Agricultural Water Management, 123(Supplement C), 103-110. doi:https://doi.org/10.1016/j.agwat.2013.03.014
van Halsema, G. E., & Vincent, L. (2012). Efficiency and productivity terms for water management: A matter of contextual relativism versus general absolutism. Agricultural Water Management, 108, 9-15. doi:https://doi.org/10.1016/j.agwat.2011.05.016
