Substratos alternativos na produção de mudas de três espécies florestais

Abstract

The process of seedling formation is important when the forest stands for productivity and quality. The objective of this work was to evaluate morphological characters and qualitative analyzes in plants, as well as physicochemical characteristics in alternative substrates used in the production of Eucalyptus urophylla, Peltophorum dubium and Eremanthus erythropappus seedlings. For this, two tests were carried out in the Forest Nursery of the Federal University of Lavras between April and December 2018. For the formulation of the substrates of the first test, the constituents were used: coconut fiber, bovine manure, charred rice husk, carbonized coffee husk and, as a control, commercial Maxfértil substrate was used. For each species, an experiment was conducted in a completely randomized design (DIC) consisting of five treatments, five replications, and the sample unit composed of 20 seedlings. For the second test, the following constituents were used: coconut fiber, commercial substrate, composted rice hulls and composted coffee hulls, with Maxfértil commercial substrate supplemented with 20% coconut fiber. In the second test, a completely randomized experiment (DIC) consisting of eight treatments, five replications, in plots composed of 20 seedlings was also installed per species. In all tests, at 120 days after germination were measured the collection diameter (DC) and height of the seedlings (H). Subsequently, the height/diameter ratio of the collection (H/DC) was calculated. For the destructive analyzes to obtain the weight of the dry matter of the aerial part (MSPA) and weight of the root dry matter (MSR), four plants were selected per plot. After the variables processed, the total dry matter weight (MST), the ratio between dry matter weight of shoot and root dry matter (RMSPAR) and Dickson quality index (IQD) were calculated. In order to evaluate the quality of the clod formed, four plants were chosen per plots and qualitative analyzes were carried out. These were: easy removal of the seedlings (FRT) and root aggregation to the substrate (AGR). Besides these analyzes, the physical and chemical characteristics of the formulated substrates were also evaluated. For the first test, the carbonized coffee husk, combined with the proportions of carbonized rice husk, coconut fiber and bovine manure presented the potential to be used as alternative constituents in the production of P. dubium and E. urophylla seedlings. For E. erythropappus, none of the formulations were indicated for the production of seedlings. For the second test, the 40% composted coffee husk, combined with 20% coconut fiber and 40% commercial substrate presented potential to be used in seedling production of E. urophylla, P. dubium and E. erythropappus.