3种整地方式下尾巨桉林分生物量动态及其与土壤水分的关系

The Variation of Biomass of Eucalyptus urophylla × E. grandis Plantations on the Leizhou Peninsula under Three Land Preparation Methods and Relationships with Soil Moisture

对3种整地方式下的尾巨桉林分生长和林地土壤水分进行了监测,通过分析各林地的林分单株平均生物量及林地土壤水分的变化,探讨二者的相互关系,以期为合理评估整地对尾巨桉林分生长和水分利用效率的影响提供科学依据。研究结果表明:随着林龄的增长,3种整地方式下尾巨桉林分单株总生物量和各器官生物量均呈增加趋势,其树干和树根所占比例逐渐增加,而树枝和树叶所占比例呈减小趋势。在幼龄期(16个月之前),全垦条件下的尾巨桉林分生长量最大,18个月后带垦的林分生长量最大;3种整地方式下的尾巨桉林地土壤水分的季节变化格局相似,与天然降水分布基本保持一致。3种整地方式中穴垦尾巨桉林地土壤有较高含水率且显著大于全垦和带垦的(P<0.05),全垦与带垦之间差异不显著;3种整地方式下尾巨桉林分单株平均生物量与耗水量之间均呈显著正相关,利用3块林分单株平均生长量及对应时间的耗水量得到了尾巨桉林分单株生长量与林分耗水量的拟合方程。

Growth and soil moisture were examined for Eucalyptus urophylla x E. grandis plantations established using three land preparation methods. Traits evaluated included average biornass per tree, soil moisture content, and then the relationship between these two traits in order to evaluate effect of site preparation method on stand growth and water use efficiency. Research results showed： although eucalypt forest plant total biomass of three species of soil preparation and biomass of different organs increased as age increased, the proportion of total biomass accounted for by branches and leaves gradually decreased whilst that accounted for by stems and roots increased. The growth amount of full cultivation was the largest in the young （to age 16 months） eucalypt plantation, and furrowing was the largest 18 months later. Seasonal variation in of soil moisture under the Eucalyptus urophylla x E. grandis plantations established under the three land preparation methods proved similar. To three land preparation methods, digging hole generally had the highest soil water content and was significantly higher than full cultivation （P〈0.05） but not significantly higher than furrowing. There was a positive correlation among the three land preparation methods in average biomass per plant and water consumption, and the fitted equation between individual tree growth and water consumption of stand was built.