Phenological relationships between meteorological extremes and agricultural yield

Abstract

Increasing temperatures with climate change and extreme events such as heat and cold waves, severe droughts, floods, storms, and hail significantly impact agricultural yield and food security. The Mediterranean Basin is particularly vulnerable in this regard. This study investigates the relationships between extreme temperature and precipitation values and agricultural yield rather than average climate parameters. Considering regional representativeness, production, and economic value, the annual wheat and barley yields of Burdur and Isparta provinces were compared with local meteorological data. Similarly, orange yields from Antalya's Finike station and olive yields from the Antalya Airport station were analyzed. Fourteen extreme temperature and precipitation indices were identified and analyzed using the ClimPACT2 software package. To eliminate linear trends in yield data caused by technological advancements, a standardization method was applied. Relationships between datasets were evaluated using Pearson's correlation coefficient. The study found significant correlation coefficients between temperature and precipitation extremes and annual cereal yield, ranging from -0.48 to 0.38, explaining 10-23% of yield variance. For annual orange yield, coefficients ranged from -0.76 to 0.87, explaining 57-75% of yield variance, while for annual olive yield, coefficients ranged from -0.63 to 0.70, explaining 39-49% of variance. A strong relationship was observed between yield values and drought or minimum temperature extremes. Significant relationships were identified during cereals' seed development and heading phases (winter-spring) and fruits' flowering and development stages (spring-summer). Under changing climatic conditions, agricultural yield and product quality are expected to be increasingly affected by extreme weather events, whose frequency and severity are escalating.