Yield implications of date and cultivar adaptation to wheat phenological shifts: a survey of farmers in Turkey

Long-term studies on ecosystems have established that climate change leads to significant shifts in the seasonal timing of recurring biological events. Crop phenological events have mostly shifted to earlier periods in the growing season than they occurred previously. A substantial body of research models the implications of these shifts on cereal yields. Yet, studies often underestimate the compensating yield effect of farmers’ autonomous adaptation efforts in the form of date adjustments and cultivar change. Adaptation estimates that are reported in the literature are almost exclusively based on crop models, not on estimated yield gains observed through farm surveys. Hence, the empirical literature on observed yield impacts of adaptation is scant, especially on important cash crops such as wheat. This paper explores the drivers of date and cultivar adaptation methods and their impacts on wheat yields in Turkey. By employing an endogenous switching regression model based on a survey of 572 farmers from three different agro-ecological zones, we find that date and cultivar adaptation increase yields of adapter households by 16% and 31%, respectively, and that non-adapter households would have benefited even more if they had adapted. The findings contribute to the interpretation of the results of modelling studies while also offering policy recommendations for planned adaptation. Policies to support farmers to practice date adaption could be implemented through the dissemination of information and knowledge on climate change, which is a low-cost option offering limited yet significant yield benefits. Public investments to develop and diffuse new cultivars that are adaptable to shifts in phenological events offer higher yield benefits.