PRODUTIVIDADE DE MINICEPAS DE CEDRO AUSTRALIANO E REMOÇÃO 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 production. 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.