HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Ringrose, C. Articles by Neilsen, W. A. Search for Related Content PubMed Articles by Ringrose, C. Articles by Neilsen, W. A. Agricola Articles by Ringrose, C. Articles by Neilsen, W. A. Related Collections Nitrogen Frozen Soils Soil Fertility and Productivity

Forest, Range & Wildland Soils

Growth Responses of Pinus radiata and Soil Changes following Periodic Fertilization

^a Forestry Tasmania, 79 Melville St., Hobart, Tasmania, 7000, Australia
^b Cooperative Research Centre for Sustainable Production Forestry, GPO Box 252-12, Hobart 7001 Australia

^* Corresponding author (carolyn.ringrose{at}forestrytas.com.au)

Low growth rates of Pinus radiata D. Don plantations on soils of low nutrient status in Tasmania require the development of nutrient management systems involving fertilization throughout the life of the stand. Periodic fertilization through 15 yr, in a Pinus radiata D. Don plantation in northeastern Tasmania was evaluated for effects on stand growth and soil. Substantial stem volume increases due to N and P fertilizer, applied as ammonium sulfate and single superphosphate were observed. Two applications of P fertilizer totaling 144 kg P ha^–1 produced substantial increases in stem volume growth from 67 to 192 m³ ha^–1. With P plus 13 annual applications of N fertilizer at 100 kg N ha^–1 yr^–1, stem volume growth increased from 192 to 344 m³ ha^–1 over the 15-yr period. Although fertilizing every second and fourth year produced less response, these treatments had better fertilizer-use efficiency. Long-term fertilization resulted in increases in concentrations of nutrients in the forest floor and the surface soil. The highest rates of fertilization were accompanied by significant reductions in soil pH throughout the soil profile, from 4.1 to 3.4 units. Reduction in pH occurred with both nitrogenous and phosphatic fertilizers. Substantial reductions in exchangeable Mg concentrations, from 235 to 88 µg g^–1, were also measured throughout the soil profile. The highest rate of N application significantly increased the total O2 horizon biomass, with N mass doubling within the O2 horizon.

Abbreviations: AAS, atomic absorption spectrometry • BA, basal area • CAI, current annual increment • DBHOB, diameter at breast height over bark • LSD, least significant difference • MAI, mean annual increment • MDH, mean dominant height • PAI, periodic annual increment • NIL, Nil treatment • (P), superphosphate only applied twice • P2YN2Y, superphosphate and ammonium sulfate applied every second year • (P)N1Y, superphosphate twice and ammonium sulfate applied annually • (P)N2Y, superphosphate twice and ammonium sulfate applied ever second year • (P)N4Y, superphosphate twice and ammonium sulfate applied every fourth year • SPH, stems ha^–1