Construction, calibration and evaluation of mini-lysimeters in the management of irrigation in a protected environment
¹Rio de Janeiro Botanical Garden Research Institute (JBRJ), 915 Pacheco Leão street, Jardim Botânico, ZIP Code: 22460-030, Rio de Janeiro, RJ, Brazil
²Federal Rural University of Rio de Janeiro (UFRRJ), Engineering Department, Seropédica Campus, Highway BR 465, Km 7, ZIP Code BR23890000, Seropédica, RJ, Brazil
³Federal Fluminense University (UFF), Department of Agricultural and Environmental Engineering, Praia Vermelha Campus, Rua Passo da Pátria, 156, ZIP Code 24210-240, Niterói, RJ, Brazil
⁴State University of Maringá, (UEM) –Ângelo Moreira da Fonseca Avenue, n. 1800, Parque Danielle, Umuarama Campus, ZIP Code 87506-370, Umuarama - PR, Brazil
*Correspondence: daianececchin@id.uff.br
Abstract:
The production of forest seedlings requires controlled environments and specific practices, highlighting the need for rational irrigation management. Historically, excessive irrigation has compromised seedling quality, underscoring the importance of developing technologies and research focused on water use efficiency in nurseries. Thus, technologies that are more financially accessible to producers contribute not only to cultivation but also to the social inclusion of these producers in broader markets. Mini-lysimeters can be effectively used to monitor the water balance in potted and tray-grown plant production, thereby reducing water waste in forest nurseries. In this study, portable electronic weighing mini-lysimeters were constructed for greenhouse evapotranspiration research using load cells (capacity: 20 kg), as sensor elements, and dataloggers for data acquisition. Calibration curves were established by correlationg standard weights and voltage readings, and were analyzed using regression analysis. The coefficient of determination () and the standard error of estimation (SEE) were used to evaluate model accuracy. Under field conditions, the lysimeters’ performance was assessed using the correlation coefficient (r); Willmott’s index (d); performance index (c) and SEE, with pine and eucalyptus seedlings. The calibration curves were well described by linear models, with values exceeding 0.994. The highest SEE (2.44 g), observedin mini-lysimeter III, remained below the 4 g detection threshold of the load cell. All performance indicators (r, d, and c) were above 0.999, with SEE values ranging from 6.2 to 36.2 g (less than 1 g per tube), demonstrating that the mini-lysimeters are suitable for monitoring daily evapotranspiration.
Key words:
evapotranspiration, forest seedlings, irrigation management, load cells, Lysimetry