IRRIGATION EFFICIENCY ON NATIVE FOREST SEEDLINGS GROWN IN RECIPIENT TUBES

A baixa qualidade de mudas pode advir de problemas na irriga\ue7\ue3o e/ou nutri\ue7\ue3o das mudas em sua fase de forma\ue7\ue3o em viveiros. Em rela\ue7\ue3o \ue0 irriga\ue7\ue3o, problemas podem surgir referentes \ue0 m\ue1 distribui\ue7\ue3o da \ue1gua ou mesmo seu manejo, levando ao deficit ou ao excesso de irriga\ue7\ue3o, enquanto o excesso pode lixiviar nutrientes, o deficit pode prejudicar o desenvolvimento da planta. Assim, o presente trabalho teve como objetivos avaliar a efici\ueancia de irriga\ue7\ue3o de um sistema de irriga\ue7\ue3o por microaspers\ue3o j\ue1 instalado em um viveiro de mudas de esp\ue9cies florestais e tamb\ue9m avaliar a efici\ueancia de um sistema de subirriga\ue7\ue3o de mudas florestais nativas cultivadas em tubetes. A avalia\ue7\ue3o da efici\ueancia da microaspers\ue3o foi realizada em um viveiro de mudas de esp\ue9cies nativas florestais na cidade de Itutinga - MG, o delineamento utilizado foi o inteiramente casualizado (DIC) em esquema de parcelas subdivididas, estando o equipamento de irriga\ue7\ue3o na parcela (tr\ueas n\uedveis: MA-20, Rondo e Inverted Rotor Spray) e tr\ueas esp\ue9cies florestais na subparcela. Na avalia\ue7\ue3o de efici\ueancia em tubetes de 300 cm\ub3, as categorias da subparcela foram: arauc\ue1ria ( Araucaria angustifolia (Bert.) O. Ktze.), jeriv\ue1 ( Syagrus romanzoffiana (Cham.) Glassman) e cutieira ( Joannesia princeps Vell.). Em tubetes de 110 cm\ub3 os tr\ueas n\uedveis da subparcela foram as esp\ue9cies: mutamba ( Guazuma ulmifolia Lam.), angico-vermelho ( Anadenanthera macrocarpa Benth.) e peroba-rosa ( Aspidosperma polyneuron Muell.). A avalia\ue7\ue3o da efici\ueancia da subirriga\ue7\ue3o foi realizada em uma estufa localizada na Universidade Federal de Lavras, em dois tanques de subirriga\ue7\ue3o em tr\ueas repeti\ue7\uf5es. As maiores efici\ueancias de aplica\ue7\ue3o foram obtidas para o emissor modelo MA-20. N\ue3o houve diferen\ue7as significativas entre a efici\ueancia de aplica\ue7\ue3o dos microaspersores em rela\ue7\ue3o \ue0s esp\ue9cies estudadas, em ambos os tubetes. A efici\ueancia de irriga\ue7\ue3o no tanque de tubetes de 300 cm\ub3 foi 90,42%, enquanto para tubetes de 110 cm\ub3 foi 92,17%. Os tanques de subirriga\ue7\ue3o mostraram-se como alternativa interessante para irriga\ue7\ue3o de mudas das esp\ue9cies florestais testadas, apresentando alta efici\ueancia para os dois tamanhos de tubetes avaliados.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 cm\ub3 tubes irrigation tank was 90.42%, while for 110 cm\ub3 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