“MONITORAMENTO DE PLANTAS DANINHAS E ANÁLISE DA MATOINTERFERÊNCIA EM PLANTIOS DE EUCALIPTO APOIADO POR RPAS”

Abstract

Reforestation in Brazil reached levels of 9.9 million hectares in 2021, exceeding the area presented in 2021 by 2%. However, in the period from 2016 to 2021, Brazil has been experiencing fluctuations in the productivity of the genera Pinus and Eucalyptus. In 2020, the average eucalyptus productivity was 36.8 m³.ha-1.year-1, a value 4.6% lower than the productivity in 2019. Interference by weed in commercial eucalyptus plantations has been one of the main causes which limit forest productivity, significantly reducing the volume of wood per hectare. The use of drones and remote sensing techniques are important tools for mapping weed and directing more assertive controls. In this sense, this work aims to understand the possible effects of the interaction of weed in commercial plantation of two eucalyptus clones, as well as evaluating the efficiency of applying a vegetation index in drone images to identify areas with existing weeds. The SaviGreen vegetation index made it possible to identify patches of weeds found in eucalyptus plantation up to 4 months of age. With the application of precision forestry concepts, weed control costs can be reduced. The main weed families found in the study area were Phyllanthaceae, Rubiaceae, Poaceae and Asteraceae. The most common species were erva-quente (Spermacoce latifolia) and brachiaria (Urochloa decumbens). Regardless of the clone, at 6 months of age nutritional deficiencies of N, P, K, Ca, Mg and S were identified. At 12 months the deficiencies were recovered, except for Mg. Both clones produced reductions of more than 35% in volume over bark and 40% in stem biomass when in contact with weed after 12 months of planting. Eucalyptus clones with slow initial growth, when coexisting with weed, present greater losses to growth in height, CBH, volume and stem biomass up to 15 months post-planting in relation to the clone with rapid initial growth.