Crescimento e percentual de emergência de plântulas de citrumeleiro 'Swingle' em função dos substratos e das doses de corretivo à base de Lithothamnium, após cem dias da semeadura

Abstract

This experiment was established aiming at evaluating the effect of six different substrates (conventional, Plantmax®, compost I, compost II, vermiculite, and muck), interacting with three different Lithothamnium doses, 0%, 5% and 10% (v/v), over the growth of citrumelo "Swingle" plantlets, until the moment of chiming. The experiment was conducted within the orchard of the Federal University of Lavras, in the state of Minas Gerais, Brazil, during the period of November 2003 until February 2004. The experimental design used was random blocks, in a factorial squeme of 6x3, with the factors constituted by six different substrates and three different Lithothamnium doses, composing thus, eighteen treatments with four repetitions. Each parcel was composed by twenty two plants. One hundred days after the planting, all the plantlets were taken off the plastic tubes, washed under tap water, and were sectioned in the base of the stem. Thus, the data of the length of each of the parts were recorded. Afterwards, the parts of the plantlets, were placed inside paper bags and transferred to forced air drying hoods, at a temperature of 75º C, during a period of 72 h. The dry weight of the canopy and root system were registered. It was observed that muck and compost I, separately, presented the best results in terms of growth and amount of dry matter. Lithothamnium evidenced as an alternative to increase nutrient availability to the citrumelo growth plantlets, but only when the pH conditions and the availability of Ca and Mg were low.