1. Nitrogen Alters Initial Growth, Fine-Root Biomass and Soil Organic Matter Properties of a Eucalyptus dunnii Maiden Plantation in a Recently Afforested Grassland in Southern Brazil
- Author
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Fernanda C.C. Oliveira, José João Lelis Leal de Souza, Emanuelle Mercês Barros Soares, Gabriel W.D. Ferreira, Lucas de Oliveira Guimarães Silva, Elias F. Araújo, and Ivo Ribeiro da Silva
- Subjects
land use change ,010504 meteorology & atmospheric sciences ,Biomass ,01 natural sciences ,Eucalyptus dunnii ,Afforestation ,Organic matter ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,δ13C ,Soil organic matter ,SOM pools ,Eucalyptus fine-root spatial distribution ,Forestry ,04 agricultural and veterinary sciences ,Soil carbon ,nitrogen fertilization ,lcsh:QK900-989 ,Eucalyptus ,chemistry ,Agronomy ,040103 agronomy & agriculture ,lcsh:Plant ecology ,0401 agriculture, forestry, and fisheries ,Environmental science - Abstract
Nitrogen (N) fertilization effects on Eucalyptus growth and soil carbon (C) stocks are still controversial. We set up an N fertilization experiment in southern Brazil to evaluate initial tree growth and changes in soil organic matter (SOM). Four N levels (24–Reference, 36, 48 and 108 kg ha−1 of N) were tested and tree growth was assessed during the first two years. Afterwards, representative trees were chosen to evaluate fine-root biomass (FRB) and its spatial distribution. Soil was sampled to a 40-cm depth and SOM was fractionated in Particulate (POM) and Mineral-Associated Organic Matter (MAOM) for C and N content, and δ13C determination. Positive N effect on tree growth was seen only for tree height. N addition resulted in higher FRB. Changes in SOM were more expressive in top-soil layers. Overall, afforestation had positive effects on soil C. Increasing reference N dose resulted in higher C and N content in both SOM fractions. C and N dynamics were tightly correlated, especially in MAOM. Eucalypt-derived C was on average three-fold higher in POM. In summary, we showed that N fertilization may have positive but limited effects on tree growth, nevertheless it enhances fine-root biomass and C and N accumulation in SOM pools.
- Published
- 2018