INTRODUCTION and AIMS: Climate changes, with their consequent increase in temperature and precipitation, have a significant impact on the soil surface. Soil temperature is very important for plant development and it
depends on humidity (soil water content), air temperature and canopy cover (Fischer et al., 2021). Canopy temperature is one of the most important physiological parameters related to transpiration, leaf water potential and stomatal conductance. Plant water status is frequently monitored using thermal remote sensing devices (Martínez et
al., 2016; Santesteban et al., 2017; Zhang et al., 2018b; Zhang et al., 2018c). Bearing in mind the mentioned
significance, the aim of this research is to analyse the effect of irrigation regime on soil temperature, soil moisture and temperature of grapevine and grass cover.
MATERIALS and METHODS: The research was conducted in the vineyard of the white wine grape variety (cv. Panonia) in Plavinci near Belgrade (44° 41’ N; 20° 41’ E; 176 m.a.s.l.) from April to September 2021. The experiment was arranged using a block design with three replications. The intra-row spacing of plants (vines) amounted to 0.9 m, while the inter-row spacing was 1.8 m (1.62 vines m-2). The vineyard was minimally tilled. The space between rows was covered by a grass-legume mixture which is the subject of this study, as well. Climate data were obtained from the meteorological station located in the vineyard. Water, physical and chemical properties of soil were determined by the standard field and laboratory analyses. Irrigation was performed using the drip irrigation method. Three irrigation regimes were established: 1) full irrigation (F), when 100% of crop evapotranspiration (ЕТс) was ensured; 2) deficit irrigation (D), 50% of ЕТс ensured and 3) drought (S), the rainfed
treatment. In all treatments soil moisture (by the vines and on the grass cover) was monitored using a gravimetric method each 7 to 10 days and continuously using TDR probes. Soil temperature probes were also used for measuring the soil temperature (soil by the vines). Temperature of the canopy cover (grapevine and grass) was measured 10 times during the vegetation (from mid-Jun to mid-September) using FLIR T335 thermal imaging camera. Three photographs were taken during each temperature measurement in all applied treatments. The photographs were later analysed using the sample of 10 temperatures per photo (30 samples per treatment) with FLIR Tools software. RESULTS and CONCLUSIONS: Soil moisture measured by means of gravimetric and TDR method was the highest in the F treatment and the lowest in the S treatment. Soil moisture content mostly remained within the soil water depletion limits during the research period. Soil temperature was the highest in the deficit irrigation treatment (it was not monitored in the control treatment). It varied from 5°С to 32.5°С and amounted to the average of 20°С from March to September. The average temperature of the grapevine canopy varied from 24.1°С in the F treatment, 25.2°С in the D treatment and 26.0°С in the S treatment. Temperature of the grapevine canopy was lower than the air temperature in all treatments, which indicates that plants were not exposed to water stress. The average temperature of grass cover in the inter-row space which was not directly irrigated varied from 38.3°С in the D treatment to 40.6 °С in the S treatment. It was mainly higher than the air temperature, which indicates that the grassland was exposed to water stress. The obtained results clearly highlight the significant impact of irrigation regime on both soil moisture and temperature and canopy cover temperature of grapevine and grass cover. In addition, grapevine tolerance to water deficit can concluded
