How does the number of water users in a land reform matter for water availability in agriculture?

Land reforms have been reported to impact agriculture, economic performances and indicators of countries along with water users and allocations. However, little is known about how land fragmentation (consolidation) in land-reform processes affects water availability. This research investigates the question of “how the number of water users is related to irrigation water allocations in land reforms,” hypothesizing that an increase in the number of water users through land fragmentation poses negative threats to water allocations through the mediation of irrigation types. We conduct empirical analyses for irrigation water demand and availability, utilizing panel data for 25 years of the post-Soviet land-reform processes from 13 regions in Sughd province, Tajikistan. Two main results are obtained: First, the irrigated areas are the main drivers that increase irrigation water demand in comparison to other factors, and the impact by pump-irrigated areas is approximately 1.6 times as large as that by gravity-irrigated areas. Second, the increasing number of water users under land fragmentation in Tajikistan tends to reduce irrigation water availability, and the magnitude of reduction under pump irrigation is more significant than that under gravity irrigation. Overall, this research establishes that irrigations and the number of water users through land reforms matter for a change in water allocations, and the interactions pose particularly idiosyncratic threats to irrigation water availability. Thus, it is advisable to reassess ongoing land-reform policies incorporating the possible negative externality of land fragmentation as well as irrigation for food security and water sustainability in agriculture.