Finding ways to stimulate the diffusion of water-saving irrigation is essential to mitigate the negative impacts of climate change on water supply. The study recently published by José Daniel Morales Martínez (UNICAMP), Alexandre Gori Maia (UNICAMP), and Junior Ruiz Garcia (UFPR) compared the factors determining the diffusion of least efficient (sprinkler systems) and most efficient irrigation (localized systems) in the Brazilian agriculture. The authors highlight how the diffusion of water-saving systems depends on knowledge flows between farmers (peer effects). On the other hand, the diffusion of least efficient systems depends fundamentally on the easy availability of water, which may become more scarce with climate change.

The study (click here for full access)adresses two central questions. The first refers to the spillover effects on the diffusion of more efficient irrigation systems, or how farmers living in one locality are influenced by irrigation and other production choices made in neighboring localities. The second refers to the  influence of environmental factors (such as easy access to water and climate variables) on the diffusion of less efficient and more efficient irrigation systems. 

The study considers the two most widely available irrigation technologies in Brazil: sprinkler irrigation, the conventional and most popular system, and localized irrigation, the most efficient and readily available alternative for water use. The results highlight that spillover effects are critical in understanding the diffusion of efficient irrigation systems. Peer effects reflect technological spillovers in the diffusion of irrigation, for example, through the transmission of successful experiences (or imitation) of irrigation in neighboring municipalities. The study also highlights that the degree of participation in cooperatives and associations plays a major role in this diffusion of more efficient irrigation systems.

The results also confirm that water supply and climatic conditions are essential factors that determine irrigation diffusion. One relevant result is that easy access to water resources is essential to the diffusion of sprinkler irrigation. At the same time, it has an insignificant impact on the diffusion of localized irrigation. One important implication is that the diffusion of localized irrigation systems may not generate conflicts over access to water resources. The climate aridification (drier seasons and warmer temperatures) is also positively associated with the diffusion of localized irrigation, i.e., farmers may adapt to climate change by adopting the most efficient irrigation systems.

The authors finally that the diffusion of more efficient irrigation systems depends fundamentally on technological spillovers and discuss how policies that stimulate interactions among farmers may ease this transmission of knowledge.