不同林龄巨尾桉人工林土壤养分变化

Soil nutrient dynamics in Eucalyptus urophylla × Eucalyptus grandis plantation at different ages

对福建省漳州市1-6 a的巨尾桉(Eucalyptus urophylla×E.grandis)人工林土壤(0-60 cm)养分进行研究。结果表明:桉树人工林土壤p H随林龄增加而升高,有效硼的变化规律与p H相反;土壤有机质、全氮、水解氮、全磷、有效磷、全钾和速效钾含量及阳离子交换量均表现为随林龄增加而显著下降,随土层深度增加而下降(全钾含量随土层深度增加而升高)。相关关系分析发现,p H与土壤有机质、全氮、有效钾、有效硼呈显著或极显著负相关关系。主成分分析法对土壤肥力进行评价,林分土壤肥力得分依次为:1 a>2 a>3 a>4 a>6 a。影响土壤肥力的主要因子是全钾、有机质、全磷、水解氮、有效硼。因此,在桉树人工林经营过程中,应注重测土配方施肥和营养诊断施肥;注重无机肥、有机肥、菌肥的配施;注重对磷肥、硼肥的施用,控制地力衰退。

To meet the nutrient demand and sustainability of plantation, soil nutrient contents of E. grandis plantation that aged from 1-6 years old were investigated at three soil depths （0-20 cm, 20-40 cm and 40-60 cm） in Zhangzhou, Fujian. Results showed that except soil pH that increased with age （P〈 0.05 ）, soil organic matter （SOM）, total nitrogen （TN）, hydrolysable nitrogen （HN）, total phosphorus （TP）, available phosphorus （AP）, total potassium （TK）, available potassium （AK）, available boron （AB） and CEC all decreased with age and soil depth （except TK increased with soil depth）. Negative correlations were all found between pH and SOM （P〈0.05）, pH and TN （P〈0.01）, AK （P〈0.01） , AB （P〈0.01）. Principal component analysis was used to test the soil fertility and was found the overall soil fertility decreased with plantation age. And the factors that dominating soil fertility were TK, SOM, TP, HN and AB. To summarize, soil nutrient diagnosis should be incorporated into plantation fertilization to maintain a balanced nutrient level. Organic fertilizer, biofertilzier, especially phosphorate and boron that are more likely to be lacking, should be taken care of during rotation period of aged plantation.