Where does this additional water for irrigation come from? The majority of irrigated land prior to the implementation of MNREGA was irrigated with water from wells. Our hypothesis indicates that farmers should have further increased their irrigated area by using water from these groundwater wells but not necessarily from other sources of irrigation. This is because, if MNREGA improved access to groundwater by facilitating recharge, it should have lowered access costs for these wells and consequently increased the area irrigated by these wells. If, by contrast, the increase in irrigated area was due to MNREGA’s improvements in other irrigation infrastructure, we should observe increases in area irrigated by non-well sources.

We can test this implication of our hypothesis directly using data from ICRISAT on the area irrigated. In Table 4 we show that farmers increase the area irrigated with water from wells by roughly 17% after the implementation of MNREGA. Like with our other outcomes, the event study (Figure 5) shows no meaningful pre-trends prior to MNREGA implementation. When we examine the change in area irrigated by canals, tanks, or “other sources” we see no significant (economic or statistical) change in area irrigated from any of these sources.<sup>20</sup> The event study for area irrigated by canals, estimated using the method in Borusyak et al. (2024), may suggest some increase in area irrigated by water from canals (Figure 5B). However, our difference-in-difference estimates (Table 4, column 2) indicate no significant change in area irrigated by canals. The point estimate suggests a small, 3% increase with wide (-9% to 16%) confidence intervals. This is confirmed by the event studies estimated using the method in Callaway and Sant’Anna (2021) which do not suggest a meaningful increase in area irrigated by canals in the post period (Figure A6).

Collectively, our results on soil moisture, irrigated crop area, and area irrigated by source all suggest that after the implementation of MNREGA farmers increase their use of irrigation. The source of the additional water that they use for irrigation comes overwhelmingly from wells rather than the other potential sources of irrigation water. That suggests that the primary way that MNREGA projects influenced the ease of irrigation was by changing the level of groundwater during the dry season. That facilitates farmers planting more area in higher value, more water intensive crops.

# **5.3 Robustness checks**

## **5.3.1 Impacts by MNREGA phase**

In order to understand how impacts might vary by MNREGA phases we re-estimate our primary model comparing only two phases at a time. This helps to address concerns about non-random assignment of districts to phases if effects are consistent across phases. We report these results in

> REGA. As the authors note, MNREGA relaxed credit constraints and implicitly provided insurance that may have allowed farmers to make riskier choices in their crop choices.

> 20The lack of change in area irrigated by canals or “other sources” is consistent with a world in which the availability of canal irrigation water is not due solely to the quality of the local infrastructure but also the infrastructure at distant locations where water is transported from, as well as the availability of water at those locations (e.g. Duflo and Pande (2007)). As a result, local improvements in canal infrastructure, made as part of MNREGA projects, might not be expected to yield the same benefits in terms of availability of irrigation water as improvements that would improve recharge rates.

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