An-Gel Sudoe pilot trial – IRTA (Lleida)

Summary

Pilot trial of the An-Gel Sudoe project aimed at assessing spring frost mitigation techniques in apple orchards and vineyards. The pilot analyses crop thermal behaviour and the soil–plant–atmosphere energy balance using advanced sensor technologies and thermal remote sensing, with the aim of generating applied knowledge to reduce the impact of frost events under real field conditions.

Description

Introduction

Spring frosts represent one of the main climatic risks for agriculture, a problem that has intensified in recent years due to climate change. Rising temperatures advance key stages of plant development, such as flowering, increasing crop vulnerability to late frost events and generating significant production losses.

Objective of the pilot trial

This pilot trial aims to assess the impact of different frost mitigation techniques in apple orchards and vineyards, analysing their effect on air temperature and crop surface temperature, as well as on the energy balance of the soil–plant–atmosphere system. To this end, advanced sensor technologies and thermal remote sensing are employed.

Activities carried out

The main activities of the pilot include:

  • installation and monitoring of sensors for continuous tracking of the energy balance,

  • development and implementation of the Bowen-ratio model for heat flux analysis,

  • analysis of winter and spring frost events,

  • acquisition of high-resolution thermal images through drone flights during real frost events.

Pilot site

The trial is carried out at two locations in the province of Lleida: the IRTA experimental station in Mollerussa, in an apple orchard under netting, and a vineyard belonging to Bodegas Raimat, Tempranillo variety, with different soil management treatments and irrigation strategies.

Preliminary results

During the winter of 2025, frost events were recorded with temperatures reaching up to −4 °C. The thermal flights conducted made it possible to identify significant temperature differences between areas with and without ground cover, as well as in areas with punctual application of heat sources, providing key information to improve frost mitigation strategies.