Litterfall and nutrient return in five tree species in a common garden experiment

Canopy litterfall is a significant pathway for return of nutrients and carbon (C) to the soil in forest ecosystems. Litterfall was studied in five even-aged stands of Norway spruce, Sitka spruce, Douglas-fir, European beech and common oak at three different locations in Denmark; two sandy sites, Ulborg and Lindet in Jutland, and one loamy site, Frederiksborg on Zealand. Litterfall was collected during three years from 1994 to 1996 in all five species and during six years from 1994 to 1999 in Norway spruce, Sitka spruce and European beech. The average total litterfall was in the range of 3200–3700 kg ha⁻¹ yr⁻¹ and did not differ significantly among tree species. There were no significant differences in total litterfall among sites during the short period, but during the longer period the richer site Frederiksborg had significantly higher total and foliar litterfall amounts compared to the more nutrient-poor sites Lindet and Ulborg. There were close relationships between foliar and total litterfall suggesting that foliar litterfall can be reliably estimated from total litterfall. Beech and oak bud scale litter was significantly related to foliar litterfall. The amount of branch and twig litter was significantly higher in oak than in other tree species. The average foliar litterfall was well related to the annual volume increment. The relationship differed markedly from previously reported relationships based on global litterfall data suggesting that such relationships are better evaluated at the regional level. Nutrient concentrations and fluxes in foliar litterfall were not significantly different among the five tree species. However, there was a significant effect of site on most nutrient concentrations of the three litterfall fractions, and foliar fluxes of P, Ca and Mn were all significantly highest at Frederiksborg and lowest at Ulborg. The similarity in litterfall inputs to the forest floor under these five tree species suggested that previous reports of large variability in forest floor accumulation should primarily be attributed to differences in litter decomposition.     

枫香人工林枯落物和土壤层养分季节变化

对枫香人工林枯落物和土壤养分季节变化进行研究。结果表明:不同季节枯落物的养分大量元素含量大小顺序是夏季>秋季>冬季>春季,含量范围是25.055~37.115 g/kg。土壤中A层大量元素含量从春季开始递减,至夏季达到最低值,秋季有所回升;B层土壤养分含量季节变化呈双峰型,但变化幅度不大.说明土壤养分含量随着深度的增加受到枯落物的影响越小,其土壤养分含量越稳定。A层土壤较容易受到枯落物季节性的影响,微量元素季节变化呈波浪型;B层土壤微量元素含量一年中始终呈现增加趋势。     

崂山茶园土壤养分水平与年变化动态研究

根据崂山绿茶重点种植区内茶园土壤的实测数据,分析了土壤有机质、碱解氮、速效磷、速效钾的分布特征及季节变化动态,并运用SPSS软件,对所选茶园的土壤养分水平进行方差分析和聚类分析。结果表明,茶园土壤养分指标因季节和地点的不同存在显著差异,根据聚类分析结果,可将茶园按土壤养分水平分为高、中、低三等,且不同等级的茶园养分均呈现明显的年变化趋势。     

云南省茶叶竞争力实证分析

本文从国内竞争力和国际竞争力两个方面入手,对云南茶叶产业的竞争力进行分析,并与中国其他茶叶生产大省进行比较分析。国内竞争力指标采用规模优势指数(简称SAI)、效率优势指数(简称EAI)和综合优势指数(简称AAI)。国际竞争力采用国际市场占有率指数（简称PRIM)、贸易竞争指数法(简称NTB)和显示性比较优势法(简称CA)进行分析。结论是: 云南茶叶国内和国际比较优势较为明显, 具有一定的竞争力, 但竞争力不稳定。     

植入乌龙茶初制工艺改进夏秋名特绿茶品质的研究

针对用夏秋季茶鲜叶加工的名特绿茶苦涩味重、收敛性强、香气清淡和综合品质较差的问题,开展了夏秋季毛峰茶加工技术研究。采用植入乌龙茶初制的部分工艺,改善了夏秋季毛峰茶品质。提出了夏秋季毛峰茶加工的技术指标和最佳工艺流程。     

贵州茶树栽培研究主要成就与展望

回顾贵州茶树栽培研究取得的主要成就,结合新阶段茶树栽培学科的态势和贵州茶产业发展的科技需求,展望未来贵州茶树栽培研究的方向。     

跳虫在茶园生态系统中的生态作用

跳虫是茶园土壤生态系统中分布极广的一类小型至微型节肢动物。它们在茶园土壤中与其它土壤动物对土壤物质循环、结构、理化性质、能流、降解化肥与农药和生物群落的维护等发挥十分重要作用。土壤跳虫的多样性以及群落结构、物种构成都反映了土壤质量和受污染状况。     

Carbon and nitrogen dynamics in early stages of forest litter decomposition as affected by nitrogen addition

The effects of nitrogen(N) availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment.Fresh litter samples including needle litter(Pinus koraiensis) and two types of broadleaf litters(Quercus mongolica and Tilia amurensis) were collected from a broadleaf-korean pine mixed forest in the northern slope of Changbai Mountain(China).Different doses of N(equal to 0, 30 and 50 kg·ha-1yr-1, respecti...     

Schima superba as a fuelbreak: Litter combustibility of three tree species with five water content levels using a cone calorimeter

To determine the suitability of Schima superba Gardn. et Champ as a fuelbreak, we compared and analyzed the flammability characteristics of tree litter from three trees commonly grown in south China, i.e., Pinus massoniana Lamb., Cunninghamia lanceolata (Lamb.) Hook., and S. superba, using a cone calorimeter at five different water content levels. Water content levels of 10%, 15%, 20%, 25% and 30% for the litter were manually produced with a new technique of adding water to dry litter. The cone calorimeter utilized a radiant heat intensity for leaf litter of 20 kW/m² (510°C) and for twig litter of 30 kW/m² (608°C). Results show that fixing the water content level by adding water with a pipette was an acceptable technique. For S. superba, compared to P. massoniana and C. lanceolata, 1) the heat release rate (HRR) was slower and lower; 2) the total heat released (THR) from the material was lower and started later in the burning process; and 3) except for the 10% water content, pkHRR/TTI was less. These results show that overall, S. superba was the best of the three species to be used as a fuelbreak in south China. __________ Translated from Scientia Silvae Sinicae, 2008, 44(5): 96–101 [译自: 林 业科学]     

Ecological process of leaf litter decomposition in tropical rainforest in Xishuangbanna, southwest China. III. Enzyme dynamics

We tested the dynamics of nine enzymes during leaf litter decomposition in Xishuangbanna tropical rain-forest both in the field and laboratory to explore the response of enzyme dynamics to decomposition under different food-web structures. We used coarse and fine (1 mm and 100 μm mesh size, respectively) litterbags in the field to create different food-web structures during litter decomposition. Most soil macrofauna such as nematodes could access only the coarse mesh litterbags, leaving only microbiota, such as mites, in the fine mesh litterbags. In the laboratory, sterilization and inoculation were adopted to investigate different enzyme dynamics with nematodes or only microbiota participating in litter decomposition. Invertase and amylase increased more for shorter food webs at the early stages of decomposition, while activities of endocellulase, β-glucosidase, xylanase and polyphenoloxydase increased to their maxima at the later stages, but greater increase occurred with extended food webs. Invertase and amylase had negative relationships and endocellulase, β-glucosidase, xylanase and polyphenoloxydase had positive relationships with litter decomposition (mass loss). The activities of enzymes responded to the process of litter decomposition. Invertase and amylase played key roles for microbiota utilizing the substrates at early stages of decomposition, while endocellulase, β-glucosidase, xylanase and polyphenoloxydase worked on the further decay of recalcitrant compounds at later stages. All enzymes related to carbon decay acted as effective indicators of litter decomposition. The decomposition of plant organic matter was essentially an enzymatic process. __________ Translated from Journal of Plant Ecology (Chinese Version), 2008, 32(3): 622–631 [译自: 植物生态学报]