Details

Autor(en) / Beteiligte

• Rance, S. J
• Myers, R. J. K
• Cameron, D. M

Titel

Dynamics of uptake, distribution and utilization of nitrogen applied at different times after planting in a Eucalyptus grandis plantation

Ist Teil von

• Plant and soil, 2009-11, Vol.324 (1-2), p.241-252

Ort / Verlag

Dordrecht: Dordrecht : Springer Netherlands

Erscheinungsjahr

2009

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• N fertilizer labelled with ¹⁵N was used to follow the accumulation and distribution of N applied at different times after planting Eucalyptus grandis W Hill ex Maiden seedlings in south-eastern Queensland, Australia. The first application was made to selected trees at 0.12 y after planting (T₀), and treated trees were harvested at intervals after. Further labelled applications were made on different sets of trees 0.50, 0.74, 1.30 and 1.49 years after T₀; T₀.₅, T₀.₇₄, T₁.₃₀ and T₁.₄₉ respectively. After 0.5 y there was no significant difference in growth between T₀ trees and unfertilized controls, but after 1 y above-ground biomass and N content of the controls was only 30% and 39% of the fertilized trees respectively (P <0.05). At later applications controls were not significantly different from fertilized trees up to 1 y later, but after 2 y above-ground biomass and N content was reduced (P <0.05). Growth reductions occurred after leaves present on the tree at the time of fertilizer application were shed. Leaf biomass and N content increased steadily to age 1.5 y and then stabilized at about 2.5 kg tree⁻¹ and 35 g tree⁻¹ respectively, new growth balanced by litter fall. N content in woody material (stems+branches) increased steadily, equaling that of the leaves at 3.5 y. N derived from fertilizer and the proportion of applied N recovered peaked at 1 y and then decreased. These relationships were not affected by time of application. In T₀ trees N in above-ground parts derived from fertilizer increased steadily to 42% of the total 0.5 y after application. It then decreased rapidly after leaf fall commenced while total N content increased. When observations ceased 3.5 y after planting, less than 5% of the N in the trees was derived from fertilizer. N uptake was two-phased. In the first year mineral N from the fertilizer was taken up by the trees. In subsequent years fertilizer contributed to the tree growth but the N taken up came from a different source.