EFICIÊNCIA DE SISTEMAS DE IRRIGAÇÃO EM MUDAS DE ESPÉCIES FLORESTAIS NATIVAS PRODUZIDAS EM TUBETES

Seedlings low quality can result due to problems in irrigation and/or nutrition of seedlings in their nursery phase . Regarding irrigation, problems can arise related to low uniformity of water application or its management , leading to lack or excess of water. While the excess can leach nutrients , the deficit can affect plant growth. Thus, this work had as objective to evaluate irrigation efficiency of a microsprinkler irrigation system at a forest native species nursery and also at sub-irrigation of forest native species being raised in recipient tubes The microsplinkler irrigation efficiency evaluation was performed in a native forest nursery at Itutinga - MG city, held in completely randomized design in split plots scheme, with the irrigation equipment on the plot (three levels: MA-20, Rondo and Inverted Rotor Spray) and three forest species on subplot. For efficiency evaluation in large tubes, the categories of subplot were: Araucaria angustifolia (Bert.) O. Ktze., Syagrus romanzoffiana (Cham.) Glassman and Joannesia princeps Vell. In small tubes, the three levels of  subplots were the species: Guazuma ulmifolia Lam., Anadenanthera macrocarpa Benth. and Aspidosperma polyneuron Muell. The sub-irrigation efficiency evaluation was conducted in a greenhouse located at UFLA, in two sub-irrigation tanks with three replications, through calculation of uniformity coefficients for each sub-irrigated species, done in three replications. The largest application efficiency was obtained for the MA-20 emitter. There were no significant differences between the application efficiency of the emitters relative to the cultivated species, in both tube sizes. The efficiency in 300 cm³ tubes irrigation tank was 90.42%, while for 110 cm³ tubes it was 92.17%. Sub-irrigation tanks proved to be an interesting alternative for irrigation of the tested forest species seedlings, with high efficiency for both tubes sizes.