Available Nitrogen and Responses to Nitrogen Fertilizer in Brazilian Eucalypt Plantations on Soils of Contrasting Texture

Forests

Ana Paula Pulito¹  José Leonardo de Moraes Gon๺lves²  Philip J. Smethurst⁸  José Carlos Arthur Junior⁷  Clayton Alcarde Alvares⁶  José Henrique Tertulino Rocha²  Ayeska H࿋ner²  Luiz Fabiano de Moraes⁹  Aline Cristina Miranda⁴  Marcos Yassuo Kamogawa³  José Luiz Gava⁹  Raul Chaves⁵  Claudio Roberto Silva¹ 

[1] Fibria S.A., Aracruz CEP: 29197-900, Brazil; E-Mails:;Department of Forest Science, Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), Piracicaba CEP:13418-900, Brazil; E-Mails:;Mathematics, Statistics and Chemistry Department, Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), Piracicaba CEP:13418-900, Brazil; E-Mail:;Department of Forest Science, “Julio de Mesquita Filho” Universidade Estadual Paulista, Botucatu CEP: 18603-970, Brazil; E-Mail:;Duratex, Agudos CEP: 17120-000, Brazil; E-Mail:;Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA; E-Mail:;Forest Science and Research Institute (IPEF), Piracicaba, CEP: 13400-970, Brazil; E-Mail:;CSIRO, Private Bag 12, Hobart TAS 7001, Australia; E-Mail:;Suzano, Itapetininga CEP: 18207-780, Brazil; E-Mails:

关键词: forest;    productivity;    potentially mineralizable N;    sustainability;    fertilizer application;    nutrition;   

DOI  :  10.3390/f6040973

来源: mdpi

【 摘 要 】

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 São Paulo state, Brazil; (b) tree growth responses to N fertilizer applied 6–18 months after planting; and (c) the relationships between N_0, other soil attributes and tree growth. We established eleven N fertilizer trials (maximum 240 kg 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 55 g 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 140–400 kg ha⁻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.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.