Aiming to evaluate net-melon fruits under irrigation management, it was carried out an experiment in greenhouse conditions. The experimental area was located at the irrigation farm of the Engineering Department of - Escola Superior de Agricultura "Luiz de Queiroz" - ESALQ/USP in Piracicaba, São Paulo, Brazil, planted with Bonus 2 cultivar. Two irrigation management systems were evaluated by tensiometer and tension lysimeter with two levels of solution fertility (presence and absence). Tension lysimeter is a device based on porous cap, capable of supplying water automatically to the plant through a Mariotte reservoir (constant hydraulic head). For the treatments with tension lysimeter, the average free water porosity (PLA) was 15%. For treatments with tensiometers, the PLA was 35% in average, favoring a good relation of air-water throughout the experiment. The temporal variation of the matrix potential in treatments by tensiometer, measured in three depths, presented an average deviation of 9.10% whereas treatments with tension lysimeter were 1.33%. The irrigation management by tensiometers without fertilizer obtained an average weight of the fruits (1,070.4 g) that was almost duplicated in relation to minimum commercial standard (550 g). However, by adding fertilizer in these plants the productivity increment was 4.5 times higher (2,493.8 g). The net-melon fruits presented a low productivity when the free water porosity was lower at 20%.
lysimeter; porous cup; Mariotte
