Fertilization in Eucalyptus urophylla plantations in Guangxi, southern China
StoraEnso decided in year 2002 to build a pulp mill in the province of Guangxi, southernChina, and also establish eucalyptus plantations to provide it with raw material. By 2010StoraEnso controls about 90 000 of planned 120 000 ha, out of 75 000 ha is already plantedwith Eucalyptus.By using better genetic material, improve the tending, selecting the sites more careful and byusing a proper fertilization regime StoraEnso hopes to increase the mean annual incrementfrom today?s 25 m3/ha, on bark, to 35 m3/ha. This study is one part in this work to increase themean annual increment in the plantation.This master thesis is the forth in a series, that has followed up a fertilization trial that startedin spring 2006 when the trial was laid out and treatments decided. The aim with the trial is toexamine the production potential of Eucalyptus urophylla in Guangxi, southern China. In totalthere are seven different treatments, out of which one is the common practice for StoraEnsoGuangxi, and one is an untreated control treatment. The three max-fertilized treatments havegotten the amounts of fertilizers decided after leaf-nutrient analysis. If the nutrient analysisrevealed that the concentration of a specific nutrient was too low, extra amounts of thatnutrient were included in the next fertilization.The treatment with the highest total production and mean annual increment at a stand age of68 months is the max-fertilized treatment: NPK-300-B with a total stem wood production of208.10 m3/ha and a MAI of 36.72 m3/ha. NPK-300-B was also the only treatment that had astatistically significant higher total production and MAI than the Control treatment.The mean basic density value was significantly lower in the wood harvested from treatmentNPK-300-B (469 kg/m3) compared to wood from the control (498 kg/m3).The leaf analysis showed that the concentrations of all nutrients have increased in bothtreatments since the last analysis in 2008 made by Rickard Carlsson and that therecommended ratios have been reached for all nutrients, except for phosphorous (P) in thecontrol which was slightly under the recommended ratio.Potential dry mass production/ ha/yr at the latitude of Guangxi is estimated to be around 30tons, if water, nutrients and other biotic factors limiting the growth is satisfied. In treatmentNPK-300-B the production reaches 14.095 tons/ha and year when the volume productionpeaked at a stand age of 68 months. So potentially the stem production is only 50% of theestimated potential.