桂西北秃杉人工林土壤理化性质

为了了解秃杉人工林对林边土壤的影响,采用野外调查结合室内分析的方法,对广西西北部的南丹县、凤山县和天峨县的秃杉人工林土壤物理、化学性质进行了研究.结果表明:不同秃杉引种区具有相似的土壤理化性质,土壤(0～40 cm)密度为0.89～1.16 g/cm3,土壤总孔隙度为43.68％～ 53.65％,土壤最大持水量为46.36％ ～ 74.61％;土壤pH为4.30 ～4.88,土壤有机质含量为17.78～68.30g/kg;土壤全氮和水解氮含量分别为0.82～3.37 g/kg和81.5～347.6 mg/kg;土壤全磷和速效磷含量为0.24～0.41 g/kg和0.40 ～ 2.87 mg/kg;土壤速效钾含量为28.3～136.2 mg/kg.表明桂西北秃杉引种栽培区林地土壤较疏松、通气、透水性能良好,土壤有机质及氮素养分含量高.随着林龄增加,林地土壤总孔隙度和最大持水量均呈增大趋势,土壤有机质、全氮和水解氮也有相同的变化规律,但土壤密度呈下降趋势.表明秃杉人工林能改善土壤结构和水分状况,提高土壤有机质和养分含量.     

不同油茶品系叶片-土壤C、N和P含量及其化学计量特征

为了解不同油茶品系的养分利用及土壤养分限制情况,以岑软2号（Camellia oleifera Cenruan 2）、岑软3号（Camellia oleifera Cenruan 3）和香花油茶1号（Camellia osmantha 1）为研究对象,分析不同油茶品系叶片与土壤碳（C）、氮（N）和磷（P）含量及其化学计量特征。结果表明,叶片C和P含量均表现为香花油茶1号>岑软2号>岑软3号,叶片N含量表现为香花油茶1号>岑软3号>岑软2号。不同油茶品系叶片N∶P均为14～16,均受N和P的双重限制。随土层深度增加,土壤C、N和P含量降低,土壤C∶P、N∶P增加。岑软2号、岑软3号叶片C、N和P含量及其化学计量特征与土壤相关指标多呈显著负相关,香花油茶1号叶片N、P含量与土壤N∶P均呈显著正相关。不同油茶品系的生长均受N、P限制;随土层深度增加,植物生长可能受P限制。     

纳板河流域不同经济林地土壤生态化学计量变化特征研究

为了研究西双版纳纳板河流域原始林转变为经济林地后,土壤的生态化学计量变化特征,在纳板河流域以5种不同经济林地(茶树林、甘蔗地、橡胶林、火龙果地和香蕉地)以及作为参考的原始林土壤作为研究对象,对土壤垂直方向上的碳氮磷养分含量及其比例的影响状况等进行研究,探讨土壤的养分变化和化学计量特征。研究结果表明:土壤碳(C)、氮(N)和磷(P)含量均不同程度表现出随土层深度增加而降低的趋势,6种不同林型中原始林和多年生橡胶林因较少受到人为活动扰动,表现出较低C,N和P含量;不同林型土壤中C∶N呈现出表层和下层低,中间层高的纺锤式分布类型;不同林型土壤中火龙果地土壤C∶P最低,而甘蔗地和香蕉地土壤中C∶P较高;原始林和橡胶林呈现低N∶P比值,而甘蔗地呈现出较高N∶P比值。相关性分析表明:C,N,P以及N∶P之间呈现出极显著正相关关系(P<0.01);C∶N和N,P之间关系显著(P<0.05);C与C∶P之间相关性极显著(P<0.01),与N∶P之间相关性显著(P<0.05)。     

不同植被类型土壤养分及生态化学计量特征研究

以望谟北盘江国家湿地公园3种不同植被类型土壤为研究对象,分析不同植被土壤养分及生态化学计量特征,为脆弱生态区域植被恢复提供技术支撑。选取乔木林、经济果树林、草地3个不同植被类型测定0—20 cm土层养分状况。结果表明：(1)在3种植被类型中,土壤C,N,P,K,AN,AP存在显著性差异;(2)土壤的C/N,C/P水平上,乔木林(18.58,84.20)、经济果树林(22.00,268.75)、草地(18.35,90.85)均高于我国陆地平均值;(3)土壤的N/P水平上,乔木林(4.51)、草地(5.13)<10,经济果树林(11.91)在10—20之间。3种植被类型中,土壤养分含量表现为乔木林>经济果树林>草地,且除AK外,其余土壤养分皆存在显著性差异。乔木林和草地土壤限制因素是N,而经济果树林是N和P。该区域在进行植被恢复管理时,可适当施加氮、磷肥,以提高土壤肥力,为植被恢复提供更多土壤养分。     

喀斯特地区人工林土壤速效养分与酶活性的季节变化

为合理管理退化的喀斯特地区新造人工林,对杜仲林、桤木林、冰脆李林的土壤速效养分和土壤酶活性的季节变化规律进行了研究。结果表明:3种林分土壤速效养分含量和土壤酶活性均表现出明显的季节动态。根据林地速效养分的减少主要由林木吸收所致,可知N肥施用,杜仲、桤木林以9月至次年1月为好,冰脆李林以11月至次年1月为好;P肥施用,杜仲、冰脆李林以7—11月或1—5月为好,桤木林以3—5月或7—9月为好;K肥施用,杜仲、桤木林以9—11月为好,冰脆李林以11月至次年3月为好。3种人工林的脲酶活性表现为春夏季高,冬季低,多酚氧化酶活性表现为春秋季高,冬季低,过氧化氢酶活性表现为秋冬季略高,春夏季略低,而碱性磷酸酶活性的季节变化3种人工林不尽相同。     

喀斯特高原山地区水源涵养林土壤及凋落物的生态化学计量特征

探明石漠化区水源涵养林凋落物与土壤化学计量特征有助于深入了解养分状况。以喀斯特高原山地区云南松(Pinus yunnanensis)+光皮桦(Betula luminifera)+银白杨(Populus alba)林、栓皮栎(Quercus variabilis)+川榛(Corylus heterophylla)林、银白杨(Populus alba)+光皮桦(Betula luminifera)林、杜鹃(Rhododendron simsii)+银白杨(Populus alba)林、光皮桦(Betula luminifera)林为对象,研究凋落物与土壤OC,TN,TP化学计量特征及内在关联。结果表明:1)表层土壤OC,TN,TP含量分别是25.02,1.56,0.33mg/g;凋落物OC,TN,TP含量分别为407.09,16.07,2.06mg/g。2)土壤C∶N为15.13,C∶P为78.40,N∶P为5.17;凋落物C∶N为25.67,C∶P为212.87,N∶P为8.38;C∶N,C∶P,N∶P均呈凋落物层土壤层。3)凋落物层、土壤层C∶P与N∶P均呈极显著正相关,土壤C∶N与凋落物C∶N,N∶P分别呈极显著正、显著负相关。4)该区土壤N,P养分亏缺,凋落物呈低C高N高P格局,土壤固持养分能力不强。     

喀斯特高原顶坛花椒生长过程中土壤养分变化特征

【目的】掌握喀斯特高原峡谷区顶坛花椒生长过程中土壤养分变化规律及土壤综合肥力情况,为其施肥管理提供参考。【方法】以亚热带喀斯特高原乡土经济植物顶坛花椒作为研究对象,采取空间代替时间的方法,以不同生长径阶(2、4、6、8 cm)的顶坛花椒代表生长过程中的不同生长发育阶段,测定其生长的土壤的养分(有机质、全氮、全磷、全钾、碱解氮、有效磷、速效钾)含量,计算土壤中C、N、P、K元素的化学计量比,并采用内梅罗指数法对顶坛花椒生长过程中土壤养分状况进行综合评价。【结果】顶坛花椒生长过程中,土壤全氮含量0.79～3.73 g/kg,全磷含量0.64～1.65 g/kg,全钾含量1.01～4.61 g/kg,碱解氮含量65.8～204.4 mg/kg,有效磷含量46.51～81.97 mg/kg,速效钾含量53.14～217.5 mg/kg,有机质含量13.07～45.94 g/kg,土壤养分含量呈现动态变化特征。在水平方向上,顶坛花椒土壤养分含量呈现变异性特征;在垂直方向上,随着土层深度的增加顶坛花椒土壤养分含量呈逐渐减少的趋势。顶坛花椒土壤的C、N、P、K化学计量比呈现出随径阶增加先降低、后升高的趋势。顶坛花椒土壤综合肥力系数为1.30～1.50,土壤肥力等级为Ⅲ级,土壤肥力随着土层深度增加总体呈现逐渐降低的趋势。【结论】喀斯特高原顶坛花椒的土壤肥力一般,在顶坛花椒生长过程中土壤养分含量水平变化特征具有变异性,垂直方向土壤养分含量具有明显的"表聚"特征。     

色季拉山西坡高海拔区土壤养分含量及化学计量特征

[目的]探究高寒生态系统土壤有机碳(SOC)、全氮(TN)、全磷(TP)、全钾(TK)含量及化学计量比的垂直分布特征.[方法]以西藏东南部色季拉山西坡海拔4200～4400 m区域为研究区,选择苔草高寒草甸(CAM)、嵩草沼泽化草甸(KSM)、林芝杜鹃灌丛(RTS)和雪山杜鹃灌丛(RAS)4种典型植被类型土壤为研究对象...     

广西扁桃适生区土壤碳氮磷生态化学计量特征

为探究广西扁桃适生区土壤碳(C)、氮(N)、磷(P)生态化学计量特征及其对环境因子的响应,采用野外调查与室内分析相结合的方法,对广西南宁、百色等扁桃适生区的土壤有机碳(SOC)、全氮(TN)、全磷(TP)及环境因素进行研究.结果表明,广西扁桃适生区土壤有机质的矿化作用慢,但土壤P表现为净矿化,具有较高的有效性.土壤C︰...     

贵州省东南部土壤氮磷对常见森林群落植物叶片的养分化学计量学特征

贵州省东南部地区是我省主要木材产区之一,分析该区域内土壤的碳、磷含量对常见森林群落植物叶片化学计量特征的影响,有助于改善该区域内的森林经营措施。研究结果表明,研究区域内植物叶片C和N含量的算术平均数分别为61.646 g/kg和7.080 g/kg,叶片P含量的几何平均数为1.241 g/kg。土壤N∶P与植物N含量及N∶P呈极显著正相关关系,与植物P呈极显著负相关关系。研究指出,在贵州省东南部地区,土壤N、P是影响植物生长的主要限制因素。     

8个泡核桃品种在广西凤山县的栽培试验初报

为了筛选能适应广西壮族自治区凤山县生态条件的优质丰产泡核桃品种,引进漾濞大泡、三台、娘青、大屁股夹绵、硬壳核桃、云新1号、小泡核桃7个泡核桃品种在该县进行了栽培试验,以当地优选的薄壳泡核桃凤优1号为对照,并对其早期表现及品种特性进行了观测与分析。结果表明:8个品种在凤山气候条件下均能正常生长、开花、结果、收获;8个品种中漾濞大泡核桃与凤优1号的生态适应性强,果实大且品质优,综合性状好,可作为当地主栽品种;云新1号早实,可作为鲜食品种在当地发展;三台核桃除坚果较小外,其他性状较优良,可作为主栽备选树种发展;小泡核桃、娘青核桃取仁较难,出仁率低,宜作为漾濞大泡核桃、云新1号、三台核桃的授粉树品种;大屁股夹绵核桃与硬壳核桃坚果果壳不易破碎,取仁难,出仁率低,经济性状差,但其生长势强,可作为治理石漠化的生态树种加以发展,却不宜作为经济树种发展。     

桉树人工林与天然林土壤养分的对比研究

在野外调查取样和室内实验分析的基础上,对人工林与天然林的土壤养分进行比较分析,结果表明人工林土壤表层的有机质、全氮、全磷、全钾含量都明显低于天然林,反映了人工林对养分的旺盛需求和消耗,并且人工林还会造成土壤阳离子交换量的降低和土壤容重的增大。提出变炼山全垦为块状整地、轮栽并适当休闲养地、提高人工林生物多样性、建立复杂的人工林群落等措施,以实现桉树人工林土壤养分平衡与生态系统的良性循环。     

云南省核桃害虫种类及其防治措施

据调查，云南省常见危害核桃的害虫有82种，对其中6种主要害虫的生活史及危害特点作了介绍，针对云南省核桃害虫的种类及危害特点，提出了综合性的防治措施。     

Development of allometric leaf area models for intensively managed black walnut (Juglans nigra L.)

? Introduction

Intensive plantation management of high-value hardwoods, such as black walnut (Juglans nigra L.), is focused on maximizing both stem form and growth at the stand and tree level. While significant research has focused on genetic improvement in black walnut, little is known about the production ecology of this species in plantation settings.

? Objectives

The aim of this study is to assess the applicability of nondestructive projected leaf area (PLA) estimation based on the pipe model theory in three single-aged J. nigra plantations representing discrete age classes ranging from 3 to 27?years of age.

? Results

Branch-level PLA was modeled as a function of branch basal cross-sectional area (R ²?=?0.875). Six nondestructive tree-level PLA models were assessed, with four models yielding R ²?>?0.90. Tree-level models performed well across age classes, with model fits comparable to previous studies in coniferous species.

? Conclusion

This study demonstrates that allometric approaches to modeling leaf area distribution in hardwoods are feasible, but future efforts may need to use different sampling approaches and/or quantify variables that have not been significant in conifers. This study represents an important first step into more quantitative analysis of production ecology of deciduous species in the CHFR of the USA.     

Soil physical characteristics and understory management in a walnut (Juglans regia L.) plantation in central Italy

Early and significant influences on soil physical properties are expected in temperate agroforests as a consequence of various soil and/or understory management practises. Soil physical characteristics were studied in an agroforestry trial of common walnut (Juglans regia L.) set up on a volcanic soil in central Italy, where clean cultivation, polyethylene mulching along tree rows and intercropping of walnut with alfalfa (Medicago sativa L.) were tested. Soil total porosity, size distribution and morphology of pores, and available water were evaluated during the second and the fourth growing season of the plantation to determine the possible influence and duration of the treatments on soil physical properties. In the first sampling the total porosity was two to three times greater than in the second one and no significant differences were found between treatments. Seasonal variation in total porosity was observed, with a maximum in summer. All dimensional classes of pores > 50 μm were well represented, thus indicating an adequate soil structure. In the fourth growing season total porosity and pore size distribution were very similar in clean cultivation and mulching so that the mulching effect on the structural characteristics of this soil was equivalent to that of repeated rototilling in clean-cultivated plots. Moreover, mulching stimulated more biological activity, resulting in a higher proportion of rounded pores. Alfalfa roots created a more homogeneous environment to a depth of 35 cm, with a greater presence of elongated pores in the range 50--500 μm that could make movement of water easier. Most of the water retained was unavailable for plants, so that competition between walnuts and alfalfa took place and could be associated with the lower stem growth of intercropped walnuts. This revised version was published online in June 2006 with corrections to the Cover Date.     

泡核桃林昆虫群落结构及其摄食功能研究

采用灯诱法,于2021年4月上旬至6月中旬对泡核桃林昆虫群落结构及其摄食功能进行研究。共诱捕到昆虫2 968头,隶属13目63科172属187种,其中74种取食植物叶片,29种刺吸植物汁液,22种捕食其他昆虫,17种取食植物花、芽、果,10种取食腐烂物,12种钻蛀植物茎干,8种为地下昆虫,5种寄生其他昆虫,4种取食植物花蜜,3种取食苔藓,3种传授植物花粉,3种取食腐木,2种取食粪,隶属13个营养生态位集团。对泡核桃造成严重危害的昆虫有核桃星尺蛾、漫绿刺蛾、星天牛、梗天牛、绿凹缘花金龟、暗异花金龟。个体数量以鳞翅目最多,鞘翅目次之,螳螂目最少;物种数以鞘翅目最多,鳞翅目次之,螳螂目最少。核桃星尺蛾、粗狭肋鳃金龟、华锐紅蝽、黑翅土白蚁为优势物种。昆虫群落组成与泡核桃林物候关系密切,在泡核桃开花、结果的高峰期,昆虫群落呈较高的多样性、均匀度分布格局。在一定程度上,捕食与寄生昆虫控制了林内害虫;食粪与腐烂物、食腐木与苔藓昆虫分解了林内有机物,促进了生态系统的物质循环。     

荔波喀斯特森林群落的生物量模型

为了准确估算喀斯特青冈栎-黄樟群落生物量,在贵州茂兰喀斯特自然保护区内,选取常绿落叶阔叶林青冈栎-黄樟群落作为基础群落,以D、D2H作为自变量,利用5种函数方程拟合群落生物量模型.结果表明:通过对标准木生物量的回归分析,以幂回归模型为最优,得出青冈栎-黄樟群落各组分生物量最优方程:W干材=168.27(D2H)0.89,W树枝=44.497(D2H)0.835 9,W树叶=19.705(D2H)0.821 7,W树皮=17.660(D2H)0.8528,W地上=250.06(D2H)0.8443.     

黔南州核桃优树叶片营养元素和果实品质相关分析

为了分析叶片营养元素对黔南州核桃优树坚果品质的影响,通过方差分析和相关分析研究了叶片营养元素与坚果品质之间的相关关系。结果表明:不同品种的核桃优树单株的坚果品质指标间存在显著差异;叶片钙、铜和锰显著影响核桃坚果品质。可以通过核桃叶片营养元素的诊断来提高坚果品质。     

Biomass,decomposition and nutrient release of Vaccinium myrtillus leaf litter in four forest stands

Biomass and nutrient transfer (N, P, K, Ca, Mg) of bilberry (Vaccinium myrtillus L.) leaf litter fall, as well as decomposition and nutrient release, were studied in four mature forest stands situated in Central and South Sweden. Bilberry leaf litter fall amounted to between 33 and 55 kg ha^‐1 yr^‐1 in the four stands. Only minor differences between sites were noted for litter concentrations of N, P and Ca, whereas K and Mg showed somewhat larger variability. Relative amounts of the five nutrient elements in the litter fall were generally in the order N > Ca > K > Mg > P. The amounts of nutrients returned to the forest floor by the annual leaf litter fall in the stands ranged from 0.4 to 0.8 kg ha^‐1 for N, 0.4 to 0.6 kg ha^‐1 for Ca, 0.2 to 0.7 kg ha^‐1 for K, 0.1 to 0.2 kg ha^‐1 for Mg and 0.04 to 0.08 kg ha^‐1 for P.

The decomposition of the local bilberry leaf litter was followed by means of litterbags during three years. At all sites there was an extremely rapid mass loss from the litter (between 45% and 54%) during the first four to five months of decomposition. After this initial phase, the decomposition rates decreased markedly and after three years the accumulated mass losses of the litters varied between 64% and 78% at the studied sites. After two and three years of decomposition, three of the sites exhibited almost similar litter mass losses whereas at the fourth site the litter was decomposed to a significantly lower degree. The pattern of nutrient release from the decomposing bilberry leaf litter differed somewhat from site to site. Minor differences were, however, noted for P, Ca and Mg while N and K were more strongly retained in the litter at one of the sites.     

Factors affecting nutrient concentration and stoichiometry of forest trees in Catalonia (NE Spain)

Although some studies have observed significant correlations between latitude and climate gradients and tree leaf nutrient concentration and stoichiometry, others have not. This study examined the nutrient concentrations of tree leaves in 3530 plots of the Catalonian Forest Inventory. Catalonia is a Mediterranean region located in NE Iberian Peninsula. It has a long land-use history and includes the large industrial-urban area of Barcelona but still contains a large forest area (42%). In the forests of Catalonia, leaf nutrient concentration increased and leaf C:nutrient ratios decreased from south to north, which paralleled the increase in MAP (mean annual precipitation) and the decrease in MAT (mean annual temperature), which was expected in a Mediterranean climate where the availability of water is the most limiting factor for plant nutrient uptake. In addition, the availability of water, which influences productivity, was associated with low leaf N:P content ratios, which is consistent with the Growth Rate Hypothesis. At a regional scale, the results support the Soil-Age Hypothesis because the youngest soils in the Pyrenees had the lowest leaf N:P ratios. Furthermore, the type of forest (evergreen, deciduous, or coniferous) explained some of the variation in leaf nutrient concentrations and stoichiometry. Nutrient concentrations were highest in deciduous trees and lowest in coniferous trees. Leaf nutrient concentrations and stoichiometry were mainly correlated with climate, but other factors such as the chemical properties of soil and rock, phylogenetics, and different ecological histories and anthropogenic factors such as pollution, had an effect.