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Available nitrogen and responses to nitrogen fertilizer in Brazilian Eucalypt plantations on soils of contrasting texture

Citation

Pulito, AP and Goncalves, JLDM and Smethurst, PJ and Arthur, JC and Alvares, CA and Rocha, JHT and Hubner, A and de Morales, LF and Miranda, AC and Kamogawa, MY and Gava, JL and Chaves, R and Silva, CR, Available nitrogen and responses to nitrogen fertilizer in Brazilian Eucalypt plantations on soils of contrasting texture, Forests, 6, (4) pp. 973-991. ISSN 1999-4907 (2015) [Refereed Article]


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Copyright Statement

Copyright 2015 The Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.3390/f6040973

Abstract

Eucalyptus plantations have seldom responded to N fertilization in tropical and subtropical regions of Brazil. This implies that rates of N mineralization have been adequate to supply tree needs. However, subsequent crop rotations with low N fertilization may result in declining concentrations of organic and potentially mineralizable N (N0), and consequent loss of wood productivity. This study investigated (a) in situ N mineralization and N0 in soils of eucalypt plantations in So Paulo state, Brazil; (b) tree growth responses to N fertilizer applied 6-18 months after planting; and (c) the relationships between N0, other soil attributes and tree growth. We established eleven N fertilizer trials (maximum 240kg ha−1 of N) in E. grandis and E. grandis x urophylla plantations. The soil types at most sites were Oxisols and Quartzipsamments, with a range of organic matter (18 to 55g kg−1) and clay contents (8% to 67%) in the 0-20 cm layer. Concentrations of N0 were measured using anaerobic incubation on soil samples collected every three months (different seasons). The samples collected in spring and summer had N0 140-400kgha−1 (10%19% total soil N), which were best correlated with soil texture and organic matter content. Rates of in situ net N mineralization (0-20 cm) ranged from 100 to 200 kg ha−1 year−1 and were not correlated with clay, total N, or N0. These high N mineralization rates resulted in a low response to N fertilizer application during the early ages of stand growth, which were highest on sandy soils. At the end of the crop rotation, the response to N fertilizer was negligible and non-significant at all sites.

Item Details

Item Type:Refereed Article
Keywords:forest, productivity, potentially mineralisable N, sustainability, fertiliser application, nutrition
Research Division:Agricultural and Veterinary Sciences
Research Group:Forestry Sciences
Research Field:Forestry Management and Environment
Objective Division:Plant Production and Plant Primary Products
Objective Group:Forestry
Objective Field:Hardwood Plantations
Author:Smethurst, PJ (Dr Philip Smethurst)
ID Code:117266
Year Published:2015
Web of Science® Times Cited:9
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2017-06-06
Last Modified:2017-09-04
Downloads:25 View Download Statistics

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