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Dendrometric evaluation of Helianthus annuus under water deficit conditions

Obročník Oliver, Bárek Viliam

Journal of Water and Land Development

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2023

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no. 59

50--53

EN

Drought is characterised as a recurring climatic phenomenon with prolonged duration, affecting land through below-average rainfall and often accompanied by high temperatures. When the available water falls below the optimum level, water deficit or water stress arises, disrupting normal plant processes. This condition poses challenges for plant growth and development as it hampers the internal water transport, induces stomatal closure, and limits access to photosynthetic resources. The study employed the annual sunflower as the experimental plant. The plants were cultivated in a controlled environment with a temperature ranging from 20 to 25°C and a humidity level of 55 to 60%, supplemented by MARS HYDRO artificial LED lighting set to a 12-h photoperiod. Radial changes in the plant stems were monitored using a DD-S type dendrometric sensor to measure radial fluctuations. The collected data were recorded in a dendrometric data logger DL 18. Data collection occurred at hourly intervals from February 20 to March 9, 2023. The nine plants were divided into three groups, each comprising three plants. All plants from groups 1 and 2 received irrigation at one-day intervals (group 1 - 80 cm3 per plant, group 2 - 40 cm3 per plant) and group 3 was not irrigated. Based on these findings, visible water stress was evident in the plants under experimental conditions. Consequently, continuous monitoring throughout the growing season will be essential to adjust the irrigation rate to meet the requirements of the plants.

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Climate Conditions Impact on the Sap Flow Into Plants and Their Dendrometric Changes

Báreková Anna, Bárek Viliam, Kováčová Martina, Novotná Beáta, Kišš Vladimír

Journal of Ecological Engineering

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2020

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Vol. 21, nr 6

224--228

EN

Water stress is an indicator that plant are suffering from drought. For optimization of the crop production is necessary to indicate physiological changes, those can be represented by stem expansion or shrinkage and sap flow rate. We used the Dynagage SGA5-WS (Dynamax) sensors for the sap flow monitoring and the sensors Diameter Dendrometer Small (Ecomatik) for measuring branches diameter changes in our research. The research was realized during two seasons, in the summer (from 31st July to 14th August 2018) and in the spring (from 27th March to 14th April 2019). The subject in our research were walnut trees (Juglans regia) situated in the private orchard in Nové Zámky area in Slovak Republic. The sap flow values in summer were on average range of 90 g•h-1, with maximum measured values above 160 g•h-1 measured after the precipitation events. After increasing of soil moisture on 1st and 2nd August 2018, it was detected the branches diameter expansion up to 0.05 mm. However, the other spring values were much lower. The sap flow reached less than 35 g•h-1 what was one third values in summer 2018. This phenomenon is a result of the low transpiration intensity of transpiration or a leafless state of trees. Although the changes in diameter were not significant in the early vegetation stage, there were monitored some fluctuation causing the diameter was shrinked by 0.2 mm due to a negative average air temperature.

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Monitoring of the Dendrometric Changes Influenced by Soil Water Content

Kišš Vladimír, Bárek Viliam, Novotná Beáta, Tátošová Lucia

Journal of Ecological Engineering

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2019

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Vol. 20, nr 1

34--38

EN

Drought is generally associated with the persistence of low precipitation amount, decreased soil moisture and water availability relative to the normal levels in a designated area. The effects of drought, range from the morphological to molecular levels, and are evident at all phenological stages of the plant growth, at whatever stage the water deficit occurs. Determination of the surface water demands for irrigation purposes comes out from the assumption of hydrologic processes stationarity. This paper shows our research prerequisite that water stress participates in an important part on the volume changes of over ground parts, which is predictive for the irrigation demand. Malus domestica var. Yellow Transparent was chosen for the measurement of volume changes of the surface plant parts. Our measurements were realised by the Diameter dendrometer small (DD-S) from 24.08. to 13.09.2017. One tree was irrigated by the dose of 50 mm. We compared the dendrometric changes to soil moisture and rainfall on both irrigated and non-irrigated trees. The experiment showed the differences between the irrigated apple tree (the diameters of the branches fluctuated between 11.9 and 12.1 mm) and the non-irrigated apple tree (the diameter of the branches increased after three-day rain from 8.35 to 8.61 mm), in order to determine the water stress of plants based on dendrometric changes and optimize irrigation during the drought period.