Journal Article

Influence of nitrogen and potassium fertilization on leaf lifespan and allocation of above-ground growth in <i>Eucalyptus</i> plantations

Jean-Paul Laclau, Julio C.R. Almeida, José Leonardo M. Gonçalves, Laurent Saint-André, Marcelo Ventura, Jacques Ranger, Rildo M. Moreira and Yann Nouvellon

in Tree Physiology

Volume 29, issue 1, pages 111-124
Published in print January 2009 | ISSN: 0829-318X
Published online January 2009 | e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/tpn010
Influence of nitrogen and potassium fertilization on leaf lifespan and allocation of above-ground growth in Eucalyptus plantations

Show Summary Details

Preview

Eucalyptus grandis (W. Hill ex Maiden) leaf traits and tree growth were studied over 3 years after the establishment of two adjacent complete randomized block designs in southern Brazil. In a nitrogen (N) input experiment, a treatment with the application of 120 kg N ha−1 was compared to a control treatment without N addition, and in a potassium (K) input experiment a control treatment without K addition was compared to a treatment with the application of 116 kg K ha−1. Young leaves were tagged 9 months after planting to estimate the effect of N and K fertilizations on leaf lifespan. Leaf mass, specific leaf area and nutrient concentrations were measured on a composite sample per plot every 28 days until the last tagged leaf fell. Successive inventories, destructive sampling of trees and leaf litter fall collection made it possible to assess the effect of N and K fertilization on the dynamics of biomass accumulation in above-ground tree components. Whilst the effects of N fertilization on tree growth only occurred in the first 24 months after planting, K fertilization increased the above-ground net primary production from 4478 to 8737 g m−2 over the first 36 months after planting. The average lifespan of tagged leaves was not modified by N addition but it increased from 111 to 149 days with K fertilization. The peak of leaf production occurred in the second year after planting (about 800 g m−2 year−1) and was not significantly modified (P < 0.05) by N and K fertilizations. By contrast, K addition significantly increased the maximum leaf standing biomass from 292 to 528 g m−2, mainly as a consequence of the increase in leaf lifespan. Potassium fertilization increased the stand biomass mainly through the enhancement in leaf area index (LAI) since growth efficiency (defined as the ratio between woody biomass production and LAI) was not significantly modified. A better understanding of the physiological processes governing the leaf lifespan is necessary to improve process-based models currently used in Eucalyptus plantations.

Keywords: biomass; Brazil; eucalypt; fertilizer; leaves; longevity; partitioning

Journal Article.  8855 words.  Illustrated.

Subjects: Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.