Application of the TDR technique for the determination of the dynamics of the spatial and temporal distribution of water uptake by plant roots during injection irrigation

• Published in: Agricultural water management Vol. 252; p. 106911
• Main Authors: Janik, Grzegorz, Kłosowicz, Izabela, Walczak, Amadeusz, Adamczewska-Sowińska, Katarzyna, Jama-Rodzeńska, Anna, Sowiński, Józef
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.06.2021
• Subjects: Injection irrigation; Intensity of elementary water uptake by plant roots; irrigation; Lactuca sativa var. capitata; lettuce; root systems; roots; soil; TDR technique; temporal variation; water management; water uptake; Intensity of elementary water uptake by plant roots; TDR technique; Injection irrigation
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/j.agwat.2021.106911

The objective of the study was to develop a method for precise estimation of spatial and temporal variation in the elementary uptake of water by roots of an irrigated plant. The project focused on plants irrigated in a unique way, consisting in injection application of water directly within the reach of the root system. The analyses were conducted on the basis of a study performed in controlled conditions, on a cubicoid physical model with dimensions of 27.00 × 30.75 × 30.75 cm. The subject of the study was butterhead lettuce of the crisphead type (Lactuca sativa L. var. capitata L.). TDR sensors were installed in the substrate in which lettuce was cultivated, for the purpose of measurement of volumetric moisture. During the period of the experiment (28 days), the values of volumetric moisture were recorded at 10-minute intervals, at 12 points in each 4.5 cm layer of the substrate. The analyses demonstrated that the maximum (as an average for the entire volume of soil within a plant root system) intensity of elementary water uptake by lettuce (maxIc∆t) was 0.0006 cm3cm−3h−1. This was observed at around midday and when the plant is being irrigated. The values of elementary intensity of water uptake by plant roots in each soil volume Ii,j,k∆t were highly varied. At the point situated the closest to the nozzle of the irrigation injector the maximum value was 0.008 cm3cm−3h−1. In a soil volume situated only 5 cm further away the maximum value was already only 0.003 cm3cm−3h−1. In many elementary soil volumes did not pick those values up. Diurnal values of Ii,j,k∆t calculated for an injection dose of 100 cm3 were, at the same points, lower than for the dose of 200 cm3. The presented method permits the acquisition of information on spatial variation and on the dynamics of the elementary intensity of water uptake by roots, which is necessary for precise determination of the location and dose of injection from the nozzle of a high-pressure irrigation injector. •Water injection to rhizosphere could be used in the irrigation of selected crops.•Application of the TDR technique to determine water uptake by plant roots.•The most intense water uptake by roots occurs in surroundings of water application.