Assessments of water deficit and heat stress for UK rapeseed cropping and their impacts on rapeseed yields

TY - JOUR

T1 - Assessments of water deficit and heat stress for UK rapeseed cropping and their impacts on rapeseed yields

AU - Hu, Biao

AU - Cutler, Mark E.J.

AU - Morel, Alexandra C.

N1 - Publisher Copyright: © 2026 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC license. http://creativecommons.org/licenses/by-nc/4.0/

PY - 2026/5/28

Y1 - 2026/5/28

N2 - The spatiotemporal patterns of water deficit and heat stress for UK rapeseed are unknown, although both stresses have been increasing due to climate change. Using historical meteorological (potential evapotranspiration (PET), rainfall and the daily maximum temperature (T max)), soil moisture (SM), and crop productivity data, this study aimed to: a) investigate the spatiotemporal distributions of water deficit and heat stress for UK rapeseed cropping from 1981 to 2020; b) assess whether defined water deficit indices are more closely associated with vegetation health indicators than UK landscape Standardised Precipitation Index (SPI)/Standardised Precipitation Evapotranspiration Index (SPEI); c) examine the stress-rapeseed yield relationships for 2016–2022. Water deficit indices, including the cumulative water deficit (CWD), integrated PET, rainfall and SM to represent crop-level water supply-demand imbalance, while heat stress index (f HS) quantified exceedance of rapeseed-specific temperature thresholds (25°C, etc.), unlike meteorological SPI/SPEI. Results showed that both stresses gradually intensified during flowering, albeit from low initial levels. Heat stress affected a larger area nationally and increased more rapidly, with coverage exceeding 51% of arable land in 2018, while regions experiencing both stresses expanded more slowly. Water deficit indices had stronger and more consistent correlations with growth status indicators of UK natural grassland (r = -0.18 to −0.70), particularly in water-limited southeastern regions (r = -0.62 to −0.70), compared to SPI/SPEI, suggesting their potential for assessing water deficit or productivity of rapeseed. Both stresses were generally negatively associated with rapeseed yields. Water deficit indices had stronger regression relationships between rapeseed yields than heat stress metrics, suggesting they were better yield predictors. The strongest relationship between rapeseed yield and CWD (p < 0.05), was observed in the northwestern region (R² = 0.92), whereas more moderate relationships were found in other three major growing regions (0.48 ≤ R2 ≤ 0.68). The predictive power of combined stress indicators for rapeseed yields varied across locations. Despite the low intensities and slowly increasing trends of the studied stresses, their negative impacts—particularly those stemming from water deficit—on rapeseed yields underscore the need for further research to develop adaptation or mitigation strategies that support precision crop management for sustainable rapeseed production in the UK.

AB - The spatiotemporal patterns of water deficit and heat stress for UK rapeseed are unknown, although both stresses have been increasing due to climate change. Using historical meteorological (potential evapotranspiration (PET), rainfall and the daily maximum temperature (T max)), soil moisture (SM), and crop productivity data, this study aimed to: a) investigate the spatiotemporal distributions of water deficit and heat stress for UK rapeseed cropping from 1981 to 2020; b) assess whether defined water deficit indices are more closely associated with vegetation health indicators than UK landscape Standardised Precipitation Index (SPI)/Standardised Precipitation Evapotranspiration Index (SPEI); c) examine the stress-rapeseed yield relationships for 2016–2022. Water deficit indices, including the cumulative water deficit (CWD), integrated PET, rainfall and SM to represent crop-level water supply-demand imbalance, while heat stress index (f HS) quantified exceedance of rapeseed-specific temperature thresholds (25°C, etc.), unlike meteorological SPI/SPEI. Results showed that both stresses gradually intensified during flowering, albeit from low initial levels. Heat stress affected a larger area nationally and increased more rapidly, with coverage exceeding 51% of arable land in 2018, while regions experiencing both stresses expanded more slowly. Water deficit indices had stronger and more consistent correlations with growth status indicators of UK natural grassland (r = -0.18 to −0.70), particularly in water-limited southeastern regions (r = -0.62 to −0.70), compared to SPI/SPEI, suggesting their potential for assessing water deficit or productivity of rapeseed. Both stresses were generally negatively associated with rapeseed yields. Water deficit indices had stronger regression relationships between rapeseed yields than heat stress metrics, suggesting they were better yield predictors. The strongest relationship between rapeseed yield and CWD (p < 0.05), was observed in the northwestern region (R² = 0.92), whereas more moderate relationships were found in other three major growing regions (0.48 ≤ R2 ≤ 0.68). The predictive power of combined stress indicators for rapeseed yields varied across locations. Despite the low intensities and slowly increasing trends of the studied stresses, their negative impacts—particularly those stemming from water deficit—on rapeseed yields underscore the need for further research to develop adaptation or mitigation strategies that support precision crop management for sustainable rapeseed production in the UK.

KW - Rapeseed

KW - Water stress

KW - Temperature stress

KW - Climate variability

KW - Yield prediction

U2 - 10.1016/j.eja.2026.128180

DO - 10.1016/j.eja.2026.128180

M3 - Article

SN - 1161-0301

VL - 179

JO - European Journal of Agronomy

JF - European Journal of Agronomy

M1 - 128180

ER -