南亚热带桉树人工林土壤肥力障碍因子评价

Analysis and Evaluation of Soil Fertility Obstacle Factors in Eucalyptus Plantation in South Subtropical Region

长期经营条件下,南亚热带区域桉树人工林土壤障碍问题频发。按土壤类型对桉树主产区进行土壤肥力障碍因子识别与评价,并给林权业主们制定区域化相应的经营、施肥策略,可针对性为提升土壤肥力提供理论依据,对保障广西人工林产业高质量、可持续发展经营具有重要意义。本文采集并分析近3年桂北地区桉树人工林主要种植区红壤、黄壤、赤红壤等土壤类型的典型样品共计298个,运用聚类分析法结合主成分分析法,从15个土壤肥力因子中筛选主要障碍因子,同时引入障碍度模型对不同土壤类型的肥力障碍因子进行定量化分析。结果表明:不同土壤类型的主要障碍因子不相同。红壤中,重度障碍因子有4个,分别为pH、全磷、有效锰、有效硼,其中pH障碍度最高(28.20%),而土壤全氮为轻度障碍因子;黄壤中,pH、全氮、有效锰、有效锌为重度障碍因子,pH障碍度最高(36.53%),全钾为轻度障碍因子;赤红壤中,重度障碍因子有3个,分别是全钾、有效镁、有效锌,其中障碍度最高的因子为有效镁(40.72%),轻度障碍因子为有机质、有效锰。由于广西短周期人工林经营普遍施用配方肥料,该区域内3种主要土壤类型的速效N、P、K养分供应较为充分,土壤障碍集中表现为酸化、低磷、部分微量元素缺失等共性问题。但因不同区域立地条件不同,建议林权业主在土壤管理过程中因地制宜,结合土壤类型制定区域化经营策略以减少土壤障碍的发生。

Under the condition of long-term management,the soil obstacle problem of eucalyptus plantation in the lower tropical region frequently occured.The identification and evaluation of soil fertility obstacle factors in main eucalyptus producing areas based on soil types,and the development of regional management and fertilization strategies for forest rights owners can provide a theoretical basis for the improvement of soil fertility,which is of great significance to ensure the high quality and sustainable development of Guangxi plantation industry.In this paper,a total of 298 typical soil samples of red soil,yellow soil and red soil in the main planting areas of eucalyptus plantations in northern Guangxi in the past three years were collected and analyzed.Cluster analysis combined with principal component analysis was used to screen the main obstacle factors from 15 soil fertility factors.The obstacle degree model was introduced to quantitatively analyze the obstacle factors of different soil types.The results showed that the main obstacle factors were different in different soil types.In red soil,there were four severe obstacle factors,which were pH,total phosphorus,available manganese and available boron,among them,pH barrier was the highest(28.20%),and soil total nitrogen was the mild disorder factor.In yellow soil,pH,total nitrogen,available manganese and available zinc were the severe obstacle factors,among them,pH barrier was the highest(36.53%),and total potassium was the mild disorder factor.In the red soil,there were three severe obstacle factors,total potassium,available magnesium and available zinc,among them,available magnesium barrier was the highest(40.72%),and the mild obstacle factor was organic matter and available manganese.Due to the widespread application of formula fertilizer in short-cycle plantation management in Guangxi,the available N,P and K nutrients of the three main soil types in this region are relatively sufficient,and the soil problems are concentrated in acidification,low phosphorus,partial trace elements loss and other common problems.However,due to the different site conditions in different regions,it is suggested that the forest right owners should develop business strategies according to the local conditions and soil types in order to reduce the occurrence of soil obstacles.