The impact of drought on the productivity of two rainfed crops in Spain

Marina Peña-Gallardo,Santiago Beguería,Sergio Martín Vicente-Serrano,Fernando Domínguez-Castro

doi:10.5194/nhess-19-1215-2019

Abstract

Abstract. Drought events are of great importance in most Mediterranean climate regions because of the diverse and costly impacts they have in various economic sectors and on the environment. The effects of this natural hazard on rainfed crops are particularly evident. In this study the impacts of drought on two representative rainfed crops in Spain (wheat and barley) were assessed. As the agriculture sector is vulnerable to climate, it is especially important to identify the most appropriate tools for monitoring the impact of the weather on crops, and particularly the impact of drought. Drought indices are the most effective tool for that purpose. Various drought indices have been used to assess the influence of drought on crop yields in Spain, including the Standardized Precipitation Evapotranspiration Index (SPEI), the Standardized Precipitation Index (SPI), the Palmer drought indices (Palmer Drought Severity Index, PDSI; Palmer Z Index, Z Index; Palmer Hydrological Drought Index, PHDI; Palmer Modified Drought Index, PMDI), and the Standardized Palmer Drought Index (SPDI). Two sets of crop yield data at different spatial scales and temporal periods were used in the analysis. The results showed that drought indices calculated at different timescales (SPI, SPEI) most closely correlated with crop yield. The results also suggested that different patterns of yield response to drought occurred depending on the region, period of the year, and the drought timescale. The differing responses across the country were related to season and the magnitude of various climate variables.

Highlights

The Mediterranean region is one of the major areas in Europe likely to be subject to the potential impacts of climate change
The Palmer Drought Severity Index (PDSI), Palmer Hydrological Drought Index (PHDI), and Palmer Modified Drought Index (PMDI) correlations were nonsignificant (p < 0.05), but the correlations for the Z Index and the multi-scalar indices were significant for most provinces and agricultural districts
The selection of drought indices was based on those commonly used to monitoring droughts worldwide, including the Standardized Precipitation Evapotranspiration Index (SPEI), the Standardized Precipitation Index (SPI), the Palmer drought indices (PDSI, Z Index, PHDI, and PMDI), and the Standardized Palmer Drought Index (SPDI)

Summary

Introduction

The Mediterranean region is one of the major areas in Europe likely to be subject to the potential impacts of climate change. It has been suggested that precipitation and temperature changes in the western Mediterranean region will lead to more severe and longer drought events in coming decades (Alcamo et al, 2007; Dai, 2011; Forzieri et al, 2016; Giorgi and Lionello, 2008; Spinoni et al, 2018; Vicente-Serrano et al, 2014) This is significant because agriculture plays a key role in food supply; in 2017 it accounted for 2.59 % of GDP in Spain, 1.92 % in Italy, and 3.53 % in Greece (World Bank, 2017). The adverse impacts of drought have been highlighted in recent severe events, including in 2003 when the agricultural

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