[目的]探究林下生态高效栽培3种药材对土壤理化性质和养分的影响.[方法]在加勒比松林下种植百部、砂仁和天冬,在种植时、种植后180 d和种植后360 d取样进行土壤pH和营养元素检测.[结果]3种药材种植后对土壤pH的影响小;有机质、全氮和速效钾的含量先增大后减小,但百部种植下的土壤全氮含量呈缓慢升高;硝态氮和有效磷含量逐渐增加;全磷和全钾逐渐减少,但天冬在种植后360 d土壤全钾含量有所升高;铵态氮含量先减少后升高.[结论]在林下种植百部、砂仁和天冬,应根据不同作物实行不同的施肥方案,在松树-百部的种植模式下,种植前期宜多施氮、磷、钾肥料,随着种植时间的增加,可以减少氮肥的施用量;在松树-砂仁的种植模式下,种植前期可以适量少施氮肥和磷肥,适当施用钾肥,在种植后期应多施氮肥、磷肥和钾肥;在松林-天冬的种植模式下,在种植前后期应多施磷、钾等肥料,施用少量氮肥,种植后期增加氮、磷肥的施用,适当施用钾肥.

研究不同间伐强度对杂交松人工林土壤理化性质和酶活性的影响,为杂交松人工林养分管理和森林经营提供理论依据.以15 a生杂交松纯林为研究对象,设计3种间伐强度,分别为弱度间伐(LT:15％)、中度间伐(MT:35％)、强度间伐(HT:50％),以未间伐林分为对照(CK).间伐3 a后,分析不同间伐强度下杂交松人工林林地土壤理化性质和酶活性差异,并采用主成分分析法(PCA)对土壤质量进行综合评价.结果显示:随着间伐强度的增大,土壤容重呈先降低后升高的趋势,而土壤持水量和孔隙度呈先升高后降低的趋势;与CK相比,间伐均能提高土壤pH及有机质与养分含量,其中,除20～40 cm土层铵态氮外,其余化学指标均表现为MT处理最好;不同间伐土壤酶活性存在明显差异,MT处理的土壤蔗糖酶和脲酶活性均显著高于CK,增幅分别为50.00％～101.89％和141.94％～184.62％,间伐后的土壤酸性磷酸酶显著高于CK,增幅为9.02％～22.30％;土壤理化性质与酶活性之间关系密切,各指标间相关性较高.由主成分分析结果可知:土壤理化性质和酶活性因子综合得分为MT>LT>HT>CK.间伐能够改善杂交松人工林土壤理化性质,提高土壤酶活性,其中,中度间伐处理对土壤质量的促进效果更加明显,对于15 a生杂交松人工林,35％的间伐强度(即保留林分密度为536株/hm2)较为合理.

澳大利亚杂交松是澳大利亚昆士兰林科所尼克斯博士用湿地松和加勒比松作亲本,人工杂交育种培育出来的松树杂交新品种.广西于20世纪80年代开始从澳大利亚引种杂交松,表现出了较强的适生性,在广西东部、南部和北部地区均有栽培.介绍杂交松的树种特性,总结广西引种澳大利亚杂交松的历程,从繁育(播种育苗、扦插育苗、组织培养、杂交可育性)、产脂等方面综述广西杂交松培育研究进展,最后探讨了杂交松人工林培育发展方向:明确主要效益,开展定向培育;科学营建杂交松混交林,促进林分健康发展;培育大径材,开展复层多元经营.

米老排作为伴生树种营建桉树-米老排混交林是一种既能保证生产效益,又能兼顾生态效益的经营方式,但何种伴生比例对于提升林分土壤碳、氮储量尚不清楚.本研究以桂南15％、25％伴生比例的桉树-米老排混交林土壤为研究对象,测定土壤有机碳、全氮含量,通过有机碳、氮储量公式计算不同林分结构土壤有机碳、氮储量.结果表明:营建桉树-米老排混交林对于土壤有机碳含量、碳氮比的提升影响显著,对土壤有机碳储量亦有正向的影响,但对土壤氮储量的影响不显著.25％的混交比例对于土壤碳氮比、有机碳储量的提升更为明显.在今后的生产经营策略中,应适当引入混交林的经营措施,并提高混交比例,实现广西人工林经营及林业下游产业的生态友好可持续发展.

Objective: To study the growth, accumulation and soil nutrient content of each overseeded species under different interharvesting intensity treatments of Eucalyptus, and to explore the best re-cultivation method suitable for mixed overseeded species after Eucalyptus interharvesting. Methods: In Guangxi state-owned Qipo forest, Eucalyptus tailorii with different planting densities (DH32-29) were mixed with Castanopsis hystrix, Mytilaria laosensis and Michelia macclurei, and four different treatments (CK, LT, MT and HT) were established for re-cultivation of Eucalyptus near-mature forests with different logging intensities, and the differences in growth conditions and soil physicochemical properties of each species were analyzed. Results: (1) As the proportion of Eucalyptus allocation decreased, the growth of Eucalyptus diameter at breast height, tree height and individual wood volume could be promoted; the growth of the three parameters of HT and MT Eucalyptus were significantly different from LT and CK. (2) The average wood volume per plant of the set species in the CK and LT treatments was Mytilaria laosensis > Michelia macclurei > Castanopsis hystrix, while in the MT and HT treatments it was Mytilaria laosensis > Castanopsis hystrix > Michelia macclurei. (3) The differences in soil aeration, total saturated water holding capacity, capillary water holding capacity, and field water holding capacity in soil layers of different depth varied. In the same soil layer, soil aeration, total porosity and capillary porosity were HT > CK > LT > MT; saturated water holding capacity and capillary water holding capacity were HT > CK > LT > MT, while field water holding capacity was CK > HT > LT > MT. (4) Organic matter, pH, total nitrogen, total phosphorus, total potassium, fast-acting nitrogen, fast-acting phosphorus, and fast-acting potassium changed with varying soil depth in each treatment.

[目的]桉树作为一种短轮伐期速生树种在我国广西等南方地区被广泛种植,单一树种连栽经营模式对林地土壤肥力质量产生重大影响,为探究当前短周期高强度连栽桉树人工林炼山经营模式是否可持续,拟对多代连栽桉树人工林的养分输入、输出特征进行研究.[方法]在4种不同代次的桉树人工林设置36个标准地,以胸径为自变量建立回归方程估算桉树人工林生物量;通过林地分等定级观测土壤肥力质量变化状况,运用冗余分析研究桉树养分含量和土壤各项指标之间的相关性;基于施肥量研究各代桉树人工林养分平衡状况.[结果]1)不同代次之间的桉树人工林生物量存在显著性差异,总体呈下降趋势,一代林至四代林的生物量分别为:125.10、151.11、107.71、116.22 t·hm-2.2)桉树人工林各器官养分含量随代次增长呈先升后降趋势,表明林地土壤肥力质量下降.3)忽略大气氮沉降和土壤微生物自身固氮等相关因素的前提下,基于全树利用和施肥量研究发现各代桉树人工林的养分输入和输出不平衡,特别是氮和磷处于养分亏缺状态.4)林地土壤肥力质量等级随代次的增加呈先升后降的趋势,表明土壤肥力质量下降、地力衰退.[结论]随着连栽代次的增加,桉树人工林生物量总体呈现降低的趋势,当前经营模式下桉树人工林的养分处于不平衡状态.同时,多代连栽造成林地土壤肥力质量下降,表明当前短周期高强度多代连栽经营方式存在不合理之处,经营可持续性较差.

Intensive management of Eucalyptus plantations has caused several social/environmental issues, including the concern over transformation of monoculture plantation cutover area. However, how different transformation patterns of Eucalyptus plantations affect soil microbial communities and their functions is unclear. In this study, the effects of different transformation patterns on structure and potential function of soil bacterial and fungal communities were evaluated. Soil chemical properties and acid phosphatase, urease, and catalase activities were also measured. In the third-generation monoculture Eucalyptus plantations, soil organic matter, nutrient contents, and microbial biomass decreased significantly and the relative abundance of oligotrophic bacteria (Chloroflexi) and symbiotic fungi (ectomycorrhizae) increased significantly compare with CK. However, in the Eucalyptus x Manglietia glauca Blume mixed plantation (E x M) and a Manglietia glauca Blume plantation (Manglietia), soil fertility (e.g., soil organic matter, total nitrogen, total phosphorus, and total potassium) improved, especially in E x M. In addition, soil acid phosphatase (0.30 mg center dot g- 1 center dot h- 1) and catalase (0.66 mg center dot g- 1 center dot h- 1) activities and the bacterial gene copies:fungal gene copies ratio (46.70) increased significantly in E x M compared with those in the monoculture plantations. The relative abundance of copiotrophic bacteria (Actinobacteria) and nitrogen cycle-associated bacteria (orders Rhizobiales and Frankiales) increased significantly in E x M. The abiotic factors soil available nitrogen and available zinc were the significant drivers of soil bacterial community structure, whereas the structure of fungal communities was most affected by tree species, in addition to soil pH and available copper. The results indicated that the E x M transformation pattern in the cutover area of Eucalyptus plantations had a significant beneficial effect on the soil fertility. The study also indicated that young plantations with Eucalyptus species have specific requirements for soil available phosphorus, available potassium, and available magnesium. Thus, increasing the supply of these nutrients during plantation development may have a positive effect on the sustainable management of plantations.

[目的]了解PM模型模拟桉树林蒸散的适用性,掌握南宁低山丘陵区的尾巨桉林蒸散特征,为编制桉树人工林生产经营方案提供参考依据.[方法]于2013年8月-2016年7月连续观测南宁桉树生态站尾巨桉林的小气候和水文数据,应用PM模型模拟尾巨桉林的蒸散量,并与水量平衡方程计算的蒸散量进行比较.[结果]月和年时间尺度的干旱指数均表明南宁低山丘陵区的尾巨桉林处于湿润或半湿润水分条件;PM模型模拟的日均蒸散量为3.5 mm/d,其中最高为9.8 mm/d;月均蒸散量为96 mm,季节间蒸散量大小顺序为夏季＞春季＞秋季＞冬季;年均蒸散量1 156 mm,占同期降水量的82％;基于水量平衡方程的蒸散量与PM模型的蒸散量差异不显著.[结论]水量平衡方程与PM模型的月蒸散量变化相似度较高,两种方法估算的尾巨桉林蒸散量差异不显著,PM模型可粗略估算尾巨桉林的蒸散量.通过提高尾巨桉林的PM模型模拟参数精度,尤其是尾巨桉林的空气动力学阻力精度,以及提高水量平衡各分量的实测精度,可进一步降低南宁低山丘陵区尾巨桉林蒸散量估算偏差,此外,研究期间的土壤含水量基本处于偏湿状态,土壤水分不成为南宁低山丘陵区尾巨桉林蒸散的限制因子.

以桉树(Eucalyptus spp.)混交林和纯林为研究对象,集成树种选择和林分结构调控等定向培育技术,构建桉树速生丰产栽培技术体系.结果表明,混交可促进桉树生长,提高林分生物量,改善土壤理化性质,桉树×红锥(Castanopsis hystrix)混交林的营林效果最好.在不同间伐强度桉树纯林林下套种米老排(Mytilaria laosensis)、红椎和火力楠(Michelia macclurei),强度间伐处理下,桉树的生长和套种树种的蓄积量表现较好;改培后的混交林能有效缓解土壤酸化,提高土壤养分含量.在桉树大径材培育中,可采用强度间伐,间伐7年后林分的蓄积量比对照林分高出20.67％.

通过研究桉树纯林与桉树和降香黄檀混交林土壤对香豆酸、香草酸和水杨酸的吸附动力学、等温吸附与解吸特性,探讨3种酚酸在不同林分土壤中的累积特征,评价桉树纯林引入降香黄檀后对林分酚酸物质累积的影响.采集5年生巨尾桉广林9号纯林及其与降香黄檀混交林地0～30 cm土层的土壤,采用添加外源酚酸方法和高效液相色谱仪检测酚酸吸附与解吸量.结果表明,3种酚酸在纯林与混交林土壤中的吸附都属于物理吸附,均表现4 h内快速吸附、4～24 h慢速吸附,随后逐渐达到吸附平衡;桉树纯林对酚酸的吸附速率大于混交林,随时间延长,纯林与混交林对酚酸的吸附速率基本一致.桉树纯林对酚酸的吸附动力学过程与Langmuir方程更吻合,而桉树与降香黄檀混交林与Elvoich方程更吻合.桉树纯林和混交林对酚酸的吸附过程与酚酸初始浓度呈正相关关系;2种林分土壤对不同酚酸的吸附量总体呈现为香豆酸>水杨酸>香草酸,且桉树纯林吸附量高于混交林;Freundlich方程能够较好地反映桉树纯林与混交林对酚酸的等温吸附特性.在2种林分土壤中香豆酸有一定的解吸率,香草酸和水杨酸解吸率较小甚至未发生解吸行为.香豆酸在高浓度400μg·mL-1时,混交林土壤的解吸率显著高于纯林,而低浓度时纯林土壤的解吸率高.

以5年生尾巨桉DH32-28萌芽林林分为研究对象,设置5种间伐强度进行比较分析,结果表明:间伐2.5年后,林分胸径生长和单株材积生长达到极显著水平;林分蓄积生长差异显著;林分树高生长差异不显著.间伐强度增大有利于胸径和单株材积的生长,间伐强度越大,胸径和单株材积增长量越大.

以修枝2a后的8a生混交林为研究对象,设置不修枝和修掉树高1/3、1/2、2/3以下枝条4种修枝处理(分别记为T0、T1、T2、T3),采用单因素随机区组设计,研究修枝对红锥-马尾松混交林生长及光环境的影响,以针对不同树种筛选适宜的修枝强度.结果表明:1)修枝显著促进了两树种的平均树高、胸径和单株材积增长,红锥和马尾松分别在T3和T2处理下达到最高值;两树种的冠幅变化表现为红锥T0>T1>T2>T3,马尾松T3>T2>T1>T0.2)适度修枝提高了红锥和马尾松树干的干物质积累量和地上总生物量,两树种分别在T3和T2处理下达到最大值;树枝、树叶生物量均表现为T0>T1>T2>T3.3)随着修枝强度的增大,两树种的叶面积指数显著减小,但平均叶倾角、透光率显著增大,增加了冠层有效光合面积,改善了林内光环境.相关性分析表明,修枝对红锥生长发育的影响比马尾松更大,促生效果更佳.综合来看,红锥和马尾松分别修枝至树高的2/3和1/2处是最适修枝高度,有利于培育红锥-马尾松复层混交林.

基于AHP法(层次分析法)构建藤蔓景观营造对森林小镇的影响、对人的影响、社会效益等3个项目层因子、7个因素层因子、22个指标层因子组成评价体系,利用九级标度法使其量化,通过求根法计算出评价体系中各指标的权重,对广西七坡森林小镇藤蔓景观期望度进行评价.结果表明:指标体系通过一致性检验,建立的判断矩阵合理可行;3个项目指标的比重大小依次为对人的影响>社会效益>对森林小镇的影响;7个因素层指标中,生态功能质量(0.7500)、心理感受质量(0.6667)、植物文化意蕴(0.5500)权重最高;在22个指标层因子中,净化空气功能综合权重最高(0.1937),植物种类多样性最低(0.0027).

通过正交设计方法三水平四因素L9(34),以使君子、紫藤和紫云藤为试验材料,研究不同品种、基质种类、生根剂类型和浸泡时间等因素对藤本植物扦插情况的影响.结果 表明:在NAA相同浓度条件下,当基质为椰糠,激素浸泡时间为10 min时,紫云藤的生根率最高,为91.7％;在相同激素浓度条件下,当以泥炭土为基质,浸泡时间10 min时,使君子的生根率最高,为87.5％.紫藤在试验中表现则较差,最高生根率仅为16.7％.

In this paper,Used 1a seeding of Michelia gioi from Qipo forest farm of Guangxi as the research material,the ef-fects of different light intensities on plant growth and development were studied. The results showed that the maximum photo-synthetic rate of photosynthetic rate was 8.12μmol/(m2?s),and the leaf superoxide(SOD) and catalase activity(CAT) were the highest in four light gradients. With the decrease of light intensity,the physiological and biochemical indexes of Michelia gioi decreased and the growth and functional structure of seedlings were inhibited. Therefore,it can be concluded that during the cultivation and breeding process,the appropriate light can improve the growth and development of nursery stock and enhance the yield and quality of firewood seedling.

Pruning of Eucalyptus urophylla×E. grandistrees grown for veneer production over a 6-year rotation was studied. The percentage recoveries of different veneer grades were compared for logs obtained from different stem heights and for logs of varying diameters. The results showed that the recoveries of Grade 1 and Grade 2 veneersfrom pruned logs were higher than from unpruned logs, and the recovery of Grade 1 veneer increased with increasing log diameter. Log height also had an impact on grades of veneer recovered from logs with the first (lowest) logs from trees yielding higher recoveries of better grades than the second logs, even where the second logs had also been pruned.

To understand the characteristics of rainfall redistribution of eucalypt plantations for improving management plan of eucalypt plantations so as to enhance capacity of water and soil conservation of forest stands,this paper did a research on monitoring outside and inside rainfall,throughfall and stemflow from July 2015 to May 2016 based on Guangxi Nanning Eucalypt Plantation Ecosystem Observation and Research Station to analyze characteristics of rainfall redistribution of a Eucalyptus urophylla × E.grandis plantation.The results showed that the total of rainfall was 1536 mm,the total of throughfall was 1042 mm,which accounted for 68％ of rainfall,the total of sternflow was 9.2 mm,which only accounted for 0.6％ of rainfall,and the total of interception was 490 mm,which accounted for 32％ of rainfall.A logarithmic function relationship was established between monthly throughfall and rainfall,and an obvious throughfall was observed when rainfall was more than 25 mm.Throughfall and throughfall rate increased with increasing rainfall intensity;when rainfall intensity was more than rainstorm,the whole outside rain nearly penetrated canopy,forming inside rain.Under the conditions of light rain,moderate rain,heavy rain and rainstorm,accumulative throughfall showed an increasing quadratic polynomial function relationship with accumulative rainfall.Meanwhile,the throughfall beginning time of light rain and moderate rain lagged behind rainfall about 20 min and 10 min,respectively;however,the time of throughfall and rainfall showed a simultaneous change tendency under the heavy rain and rainstorm.In spite of too little stemflow which was ignored in the process of rainfall redistribution estimation,its role should not be neglected.Monthly rain showed a positive power function relationship with monthly interception,but a negative exponential function relationship with interception rate.

With an aim to give insights on Eucalyptus plantation management,this studyconducted a five-year monitoring on land surface runoff,soil erosion and soil fertility in a forest with two managements,i.e.,Eucalyptus-grass and Eucalyptus plantations and then comprehensively analyzed and investigatedthe impacts of Eucalyptus-grass plantation on water and soil erosion,as well as soil fertility.The analysis showed that the land surface runoff and soil erosion presented the same decreasing trend with time under the Eucalyptus plantation as under the Eucalyptus-grass plantation and were larger under the former than under the latter plantation.Under the Eucalyptus plantation,they ranged from 27.4 m3 hm-2 a-1 to 6612 m3 hm-2 a-1 and 0 t hm-2 a-1 to 14.9 t hm-2 a-1,respectively,and particularly water and soil erosion happened only in the first two years.Under the Eucalyptus-grass plantation,they decreased by 20.84％-82.85％ Eucalyptus-grass and Eucalyptus plantations increased soil pH by 0.03-0.05 and 0.14-0.18,respectively,and soil organic matter contents,total N,total P,total K,alkalytic N,available P and rapidly available K (except for exchangeable Ca and Mg) by 0.13-3.00 times and 0.39-2.11 times,respectively,when compared with the land beforetree-planting.The correlation degree of soil fertility decreased as follows:Eucalyptus-grass ＞ Eucalyptus ＞ land before tree-planting.The increases in soil nutrient contents and correlation degree between them under the two plantations were larger in 0-20 cm soil layer than in 20-40 cm soil layer.Therefore,the intercropping grass with Eucalyptus improved soil fertility and should be a better compound management for sustainable development of Eucalyptus plantation,compared with simple Eucalyptus plantation.

In different planting density and land conditions of Eucalyptus plantations, the different agroforestry pat-terns with forages growing was studied by planting Tephrosia candida, (Pennisetum americanum×Pennisetum purpure-um) ×Pennisetum purpureum schum.cv.Mott and Stylosanthes guianensias SW, and the biological yield and economic returns of these agroforestry managements were investigated and analyzed.The results showed that Eucalyptus planta-tion with interplantion of forages could effectively promote the growth of Eucalyptus, and each model had a increased wood accumulation volume in each unit area with 0.63% ~22.58%compared with that of pure Eucalyptus planta-tions , the total net income increased by 9.85% ~19.77%.Annual net yield of different land conditions and den-sity varied significantly.In general, the pattern of Tephrosia candida growing in Eucalyptus (2 m×6 m) is worth to popularization.

[Objective] To study water,soil and nutrients loss of Eucalyptus plantation in Qipo forestry station in Guangxi Province.[Method] Based on location and continuous observation with a runoff plot,effects of the intercropped herbage on soil erosion and nutrient loss in Eucalyptus plantation were analyzed.[Result] The results showed that the annual surface runoff amount of different vegetation types were Eucalyptus plantation(2 919.50 m3/hm2) > Eucalyptus + Guimu No.1 grass(2 219.42 m3/hm2) and the seasonal variation of surface runoff amount were summer > spring > autumn >winter,which is basically coincided with the seasonal distribution of precipitation in this region.The amount of soil erosion were Eucalyptus + Guimu No.1 grass(4.125 t/hm2·a)>Eucalyptus plantation(3.835 t/hm2·a),Eucalyptus grass was high proportion on soil erosion,and Eucalyptus plantation loss in surfaced runoff.The amount of soil nutrients loss were Eucalyptus grass(4.388 5 kg/hm2·a)>Eucalyptus plantation(4.303 1 kg/hm2·a)which coincided with the law of the amount of soil erosion and the soil nutrient showed as organic matter>Ca>K>N>P>Mg>Zn>B>Cu.[Conclusion] It was concluded that the surface runoff amount of Eucalyptus plantation with different vegetation types had significant difference in this region,but their soil nutrients and nutrient loss amount have no significant difference.