Summary:

The experiment concerning irrigation controlling of gerbera cultivated in containers was done in 2012. Usually gerbera plants cultivated for cut flower production are irrigated using drippers. Correct adjustment of plant fertigation of plants grown in pots (volume and frequency of application) strongly influenced physical and chemical paramertes of growing media, plant productivity, flower quality. The systems controlling irrigation should also have the possiblity to prevent excessive leaching of nutrient solution during the period when plants requirements decreased due to unfavorable weather conditions. The aim of the experiment was to compare the effects of three methods of controlling irrigation on growth and flowering of gerbera ‘Surabaja' cultivated in containers (2 dm-3). The water consumption and leaching in each irragation treatment was also evaluated. Irrigation control systems were as follows: I - con-trol (irrigation 3 times a day, irrespectively of weather conditions, II - automatically controlled irrigation, according to water sensor readings in growing medium), III - automatically controlled irrigation according continuous readings of plant weight (all plants placed on special balance connected with irrigation controller). The aim of the experiment was to evaluate the precise control of irrigation of gerbera plants using specially designed balance, according to plant requirements and environment changes in greenhouse (temperature, humidity, solar radiation). The nutrient solution was identical in all irrigation tratments: N 170, P 34, K 200, Mg 30, Ca 140 (mg/l) + microelements. The water consumption in III treatment (plants irrigated according to plant weight changes) was the highest, however this treatment gave the highest flower yield and the best flower quality (flower diameter and flower weight). The lowest yield gave plants in control treatment (I), (irrigated three times daily, irrespectively of weather conditions). In this treatment the periodical excessive watering was observed, resulted in high daily leaching of nutrient solution and increase of salinity in growing medium. The obtained result showed that irrigation control system using specially designed balance connected to the computer gave very good results in gerbera cultivation. The daily water doses were strongly correlated with solar radiation and temperature in greenhouse (R2 = 0,70). In case of treatment II - irrigation controlled with capacitance sensor, according to water content in growing medium, the correlation between water dose and climate parameters (solar radiation and temperature) was not so strong (R2 = 0,21).