Introducing Acacia mangium trees in Eucalyptus grandis plantations: consequences for soil organic matter stocks and nitrogen mineralization

Abstract

Background and aims Eucalyptus plantations cover 20 million hectares on highly weathered soils. Large amounts of nitrogen (N) exported during harvesting lead to concerns about their sustainability. Our goal was to assess the potential of introducing A. mangium trees in highly productive Eucalyptus plantations to enhance soil organic matter stocks and N availability. Methods A randomized block design was set up in a Brazilian Ferralsol soil to assess the effects of mono-specific Eucalyptus grandis (100E) and Acacia mangium (100A) stands and mixed plantations (50A:50E) on soil organic matter stocks and net N mineralization. Results A 6-year rotation of mono-specific A. mangium plantations led to carbon (C) and N stocks in the forest floor that were 44% lower and 86% higher than in pure E. grandis stands, respectively. Carbon and N stocks were not significantly different between the three treatments in the 0-15 cm soil layer. Field incubations conducted every 4 weeks for the two last years of the rotation estimated net soil N mineralization in 100A and 100E at 124 and 64 kg ha?1 yr?1, respectively. Nitrogen inputs to soil with litterfall were of the same order as net N mineralization. Conclusions Acacia mangium trees largely increased the turnover rate of N in the topsoil. Introducing A. mangium trees might improve mineral N availability in soils where commercial Eucalyptus plantations have been managed for a long time. (Résumé d'auteur

Reforestation of a Degraded Area with Eucalyptus and Sesbania: Microbial Activity and Chemical Soil Properties

“…These species can contribute to the nutrition and biomass production of Eucalyptus by increasing N availability in the soil and accelerating the nutrient cycling process (Rodrigues et al, 2003;Forrester et al, 2004;Voigtlaender et al, 2012;Silva et al, 2013;Koutika et al, 2014;Paula et al, 2015). In addition, legumes can favor the formation of humic substances in the soil, which increases the C stock and improves soil chemical properties (Vezzani et al, 2001;Garay et al, 2003;Mendonça et al, 2008;Schiavo et al, 2009;Forrester et al, 2013;Koutika et al, 2014).…”

Leaf Total Nitrogen Concentration as an Indicator of Nitrogen Status for Plantlets and Young Plants of Eucalyptus Clones

“…However, in nectarine trees (prunus persica), total N concentration showed In general, total N and NH + 4 -N concentrations were higher in the upper soil layers (Table 3) because, in them, there is greater organic matter (OM) concentration, and more than 95 % of total N in the soil is found in organic forms (Cantarella, 2007). Similar values of total N were found in the soil under eucalyptus plantations in the State of São Paulo (Voigtlaender et al, 2012). In contrast, there was greater variability for NO − 3 -N concentrations in the different soil layers, probably because NO − 3 -N ions are highly mobile and subject to leaching in soils (Cantarella, 2007).…”

“…However, in the rainy season, leaf concentrations were greater in the sandy soil (João Pinheiro region) and did not effectively represent total N concentrations in the soil. In the rainy season, mineralization of soil organic matter (OM) is favored and, since the clayey soil had more OC (Table 1) and total N (Table 3), higher release of N was expected, along with greater leaf total N. The highest amounts of mineral N in the 0-20 cm soil layer were found during the rainy and hot seasons in an E. grandis plantation (Voigtlaender et al, 2012), confirming higher N mineralization in the soil in the rainy season. This shows the importance of standardizing the correct sampling time, which, in this case, would be the dry season for total N in the leaf.…”

Investigation of Root Distribution and Tensile Strength of Acacia mangium Willd (Fabaceae) in the Rainforest

“…Acacia mangium is a fast growing species (Butcher et al, 2000;Galiana et al, 1990;Voigtlaender et al, 2012) with annual wood production by 17-20 m 3 ha -1 year -1 during a period of 10-12 years (Galiana et al, 1990). This species is from Fabaceae family, fix nitrogen in the soil, generally used in agroforestry with higher beneficial components to the plants for its nitrogen fixation (Jeyanny et al, 2010).…”