| 摘要: |
| 【目的】研究桉树人工混交林中各树种的生长状况、蓄积量和土壤养分含量，探索适于桉树生长的最佳混交模式。【方法】在广东省雷州半岛，选择尾巨桉（DH32-29）分别与团花、马占相思、湿加松混交的试验林和桉树纯林为研究对象，采用随机抽样法测定各树种的胸径、树高、枝下高和冠幅;并在各样地四角以及中心设5个土壤采样点，采集表层0～20 cm的土壤，测定试验林地土壤pH及有机质、全氮、全磷、全钾、碱解氮、速效磷、速效钾、有效硼含量。【结果】（1）团花、马占相思、湿加松均可促进桉树胸径、树高和单株材积生长，促进作用大小表现为马占相思＞团花＞湿加松；4个林分间桉树胸径存在显著差异，树高、枝下高、冠幅和单株材积均存在极显著差异。（2）团花和马占相思的平均胸径、平均冠幅和平均单株材积皆大于同一林分内的桉树，而湿加松的平均胸径、平均树高、平均冠幅和平均单株材积均远小于同一林分内的桉树。（3）各类型混交林中，桉树的单位面积蓄积量大小为桉树湿加松混交林＞桉树马占相思混交林＞桉树团花混交林，混交树种的单位面积蓄积量大小为团花＞马占相思＞湿加松，总的单位面积蓄积量则以桉树马占相思混交林最大，桉树团花混交林次之。（4）桉树与团花混交后，林地土壤pH及有机质、碱解氮、速效钾含量均极显著高于桉树纯林地；桉树与马占相思混交后，林地有机质、碱解氮、全钾和速效钾含量显著或极显著高于桉树纯林地；桉树与湿加松混交后，林地仅土壤pH和全磷含量显著或极显著高于桉树纯林地。【结论】桉树与马占相思混交后，桉树的胸径、树高、单株材积生长最好，林分整体蓄积最大，林地表层土壤养分含量最高，林分质量最好，林分结构最稳定。 |
| 关键词: 尾巨桉 混交林 林分生长 土壤养分 |
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| 基金项目:江西省科技合作领域重点项目“红豆属珍贵濒危树种种苗产业化合作示范项目”(20161BBH80065)；江西省林业科学院重点项目“低效阔叶林质量提升关键技术研究”（2017511201） |
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| Growth and soil nutrient of Eucalyptus mixed plantations |
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DENG Haiyan,MO Xiaoyong,MEI Jiayi,et al
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| Abstract: |
| 【Objective】This paper studied the growth of different tree species,stand volume and contents of soil nutrients in Eucalyptus mixed plantations to explore the best mixed pattern for Eucalyptus growth.【Method】This paper selected the single species plantation of Eucalyptus urophylla×E. grandis (DH32-29) and its mixed species plantations with Neolamarckia cadamba,Acacia mangium and Pinus elliottii×P. caribaea on Leizhou Peninsula,Guangdong.The diameter at breast height (DBH),height,height under branches and crown width of each tree species were measured with random sampling method.Five soil sampling sites in the four corners and the center of each plot were also set up to collected soil samples at the top with-depth of 0-20 cm for measuring soil pH and contents of organic matter,total nitrogen,total phosphorus,total potassium,alkali hydrolyzable nitrogen,available phosphorus,available potassium and available boron.【Result】(1) N. cadamba,A. mangium and P. elliottii×P. caribaea all promoted the growth of DBH,height and individual volume of Eucalyptus with the order of A. mangium>N. cadamba>P. elliottii×P. caribaea.Among the four plantations,there were significant differences in DBH and extremely significant differences in height, height under branches,crown width and individual volume of Eucalyptus.(2) The mean DBH,average crown width and average individual volume of N.cadamba and A.mangium were all larger than those of Eucalyptus in each mixed plantation,while the mean DBH,average height,average crown width and average individual volume of P. elliottii×P. caribaea were much smaller than those of Eucalyptus in their mixed plantations.(3) In the various types of mixed plantations,the Eucalyptus mixed with P. elliottii×P. caribaea had the largest volume per unit area,followed by those mixed with A.mangium and N.cadamba with the decreasing order of N. cadamba>A. mangium>P. elliottii×P. caribaea.The total stand volume per unit area of the mixed plantation of Eucalyptus and A. mangium was the largest,followed by the mixed plantation of Eucalyptus and N. cadamba.(4) After Eucalyptus were mixed with N. cadamba,soil pH and contents of organic matter,alkali hydrolyzable nitrogen and available potassium were all very significantly higher than those in pure Eucalyptus forestland.After Eucalyptus were mixed with A. mangium,contents of organic matter,alkali hydrolyzable nitrogen,total potassium and available potassium were significantly or very significantly higher than those in pure Eucalyptus forestland.After Eucalyptus were mixed with P. elliottii×P. caribaea,only soil pH and total phosphorus content were significantly or very significantly higher than those in pure Eucalyptus forestland.【Conclusion】After Eucalyptus were mixed with A. mangium,DBH,height and individual volume of Eucalyptus grew the best and the stand volume and soil nutrient contents were the largest with best stand quality and most stable structure. |
| Key words: Eucalyptus urophylla×E. grandis mixed plantation stand growth soil nutrient |
