Maintenance of the Economic Performance of Eucalyptus in Competition With Weeds

Kaléo D Pereira,Suany C T Nunes,Marcos A P Gama,Dênmora G Araújo,Jonas E C Rocha,Rafael G Viana,Norberto C Noronha

doi:10.5539/jas.v11n7p60

Abstract

The aim of this study was to evaluate the growth of the hybrid clone Eucalyptus grandis &times; Eucalyptus urophylla submitted to competition with weeds and determine the period prior to economic loss (PPEL). The experiment was carried out in Ulian&oacute;polis, Par&aacute; State, Brazil, and consisted of the treatments continuous control and no control of weeds. Weed management was carried out by integrating both mechanical and chemical control. Stem base diameter, height, canopy diameter of eucalyptus plants were measured on the 16th month after planting. Wood volume was estimated by means of a volumetric equation. The treatments continuous control and no control of weeds were compared using the Hotelling&rsquo;s T2 test and the parameters for PPEL calculation were defined from volume estimation. The treatment continuous control promoted significant gains in eucalyptus growth. PPEL tended to be reduced by 3.8287 and 0.2393 units with the increase of a unit in the price of wood and the increase of planting yield, respectively. For different eucalyptus wood prices, the calculated PPEL ranged from 40 to 161 days of coexistence with weeds.

Highlights

The establishment of planted forests has gained increasing prominence in the forest sector, following the trend of sustainable development of wood production
The most common is intra- and interspecific competition, which tends to occur from the moment that two or more individuals develop in the same space and are dependent on the same limited resources for their survival, such as water, nutrients, light, and space in the case of plants (Odum, 2004; Pereira et al, 2014)
From the Hotelling’s T2 test for treatment comparison, a significant difference was observed between the continuous control (CC) and no control (NC) of weeds

Summary

Introduction

The establishment of planted forests has gained increasing prominence in the forest sector, following the trend of sustainable development of wood production. The most common is intra- and interspecific competition, which tends to occur from the moment that two or more individuals develop in the same space and are dependent on the same limited resources for their survival, such as water, nutrients, light, and space in the case of plants (Odum, 2004; Pereira et al, 2014) This phenomenon is one of the challenges for the success of commercial reforestation since weed occurrence damages planting productivity and leads to complications in operational activities (Pitelli, 1987; Londero, Schumacher, Ramos, Ramiro, & Szymczak, 2012). In the management of eucalyptus plantations, weed control is a factor of considerable relevance for wood productivity and final net income, representing around 20-25% of the total cost in a 7-year cycle (Rodigheri, Pinto, & Dhlson, 2001; Queiroz & Silva, 2016)

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