PRODUTIVIDADE DE MINICEPAS DE CEDRO AUSTRALIANO E REMO\uc7\uc3O DE NUTRIENTES PELA COLETA SUCESSIVA DE MINIESTACAS

Abstract

The management of ministumps to produce minicuttings results in the continuous removal of nutrients and it is necessary replacement to avoid depletion and decline in production. Thus, it is necessary to determine the amount of nutrients removed over time, in different management models, to enable commercial mulproduction. The objective of this study was to evaluate two minigarden multiclonal systems of Toona ciliata , in plastic tubes and bed, for productivity and nutrients removal over time by ministumps, produced by seeds, submitted to successive collections of minicuttings. One hundred and eighty-six seedlings were used in each management system. In this paper, it was determined the nutrient content in shoots issued by 20 ministumps randomly selected in each system. Five shoots were collected at intervals of 32 days in bed system, while in the plastic tubes system three shoots were collected at intervals of 31 days. The data were analyzed by a sample simple random considering an infinite population of minicuttings. The qualitative treatment average was compared by confidence interval using the Student t test, 5% probability, and the quantitative treatment (productivity and nutrients removed in time by ministumps) by regression. It has been found that the productivity and nutrient contents removed by ministumps in bed were higher than in the plastic tubes. Nitrogen and potassium are the nutrients most removed by ministumps in both systems. Here, it was presented the curves corresponding to the nutrients exported, to estimate the replacement that will be made in each system over time.O manejo de minicepas para produ\ue7\ue3o de miniestacas resulta na remo\ue7\ue3o cont\uednua de nutrientes, sendo indispens\ue1vel sua reposi\ue7\ue3o para evitar o esgotamento e queda na produ\ue7\ue3o. Assim, \ue9 necess\ue1rio determinar a quantidade de nutrientes removidos no tempo, em diferentes modelos de manejo, para viabilizar a produ\ue7\ue3o comercial. O objetivo deste trabalho foi avaliar dois sistemas de minijardim multiclonal de Toona ciliata , conduzidos em tubete e canalet\ue3o, quanto \ue0 produtividade e remo\ue7\ue3o de nutrientes ao longo do tempo pelas minicepas, produzidas por via seminal, submetidas a coletas sucessivas de miniestacas. Foram utilizadas 186 mudas em cada sistema de manejo. Foram determinados os conte\ufados de nutrientes nas brota\ue7\uf5es emitidas por 20 minicepas selecionadas ao acaso em cada sistema. Foram realizadas cinco coletas de brota\ue7\uf5es em intervalos m\ue9dios de 32 dias no sistema canalet\ue3o, enquanto no sistema tubete foram realizadas tr\ueas coletas de brota\ue7\uf5es em intervalos m\ue9dios de 31 dias. Os dados foram analisados por amostragem simples ao acaso considerando uma popula\ue7\ue3o infinita de miniestacas. As m\ue9dias dos tratamentos qualitativos foram comparadas por intervalo de confian\ue7a, utilizando o teste \u201ct\u201d de Student, a 5% de probabilidade, e os tratamentos quantitativos (produtividade e nutrientes removidos no tempo pelas minicepas) por regress\ue3o. Foi constatado que a produtividade e o conte\ufado de nutrientes removidos pelas minicepas manejadas em canalet\ue3o foram superiores \ue0 dos tubetes. O nitrog\ueanio e o pot\ue1ssio foram os nutrientes mais removidos pelas minicepas em ambos os sistemas de manejo. S\ue3o apresentadas as equa\ue7\uf5es que descrevem as quantidades removidas ao longo do tempo nos dois sistemas