Nitrogen Leaching of Two Forest Ecosystems in a Karst Watershed

Karst watersheds are a major source of drinking water in the European Alps. These watersheds exhibit quick response times and low residence times, which might make karst aquifers more vulnerable to elevated nitrogen (N) deposition than non-karst watersheds. We summarize 13 years of monitoring NO ₃ ^? , NH ₄ ⁺ , and total N in two forest ecosystems, a Norway spruce (Picea abies (L.) Karst.) forest on Cambisols/Stagnosols (IP I) and a mixed beech (Fagus sylvatica L.) spruce forest on Leptosols (IP II). N fluxes are calculated by multiplying concentrations, measured in biweekly intervals, with hydrological fluxes predicted from a hydrological model. The total N deposition in the throughfall amounts to 26.8 and 21.1 kg/ha/year in IP I and IP II, respectively, which is high compared to depositions found in other European forest ecosystems. While the shallow Leptosols at IP II accumulated on average 9.2 kg/ha/year of N between 1999 and 2006, the N budgets of the Cambisols/Stagnosols at IP I were equaled over the study period but show high inter-annual variation. Between 1999 and 2006, on average, 9 kg/ha/year of DON and 20 kg/ha/year of DIN were output with seepage water of IP I but only 4.5 kg/ha/year of DON and 7.7 kg/ha/year of DIN at IP II. Despite high DIN leaching, neither IP I nor IP II showed further signs of N saturation in their organic layer C/N ratios, N mineralization, or leaf N content. The N budget over all years was dominated by a few extreme output events. Nitrate leaching rates at both forest ecosystems correlated the most with years of above average snow accumulation (but only for IP I this correlation is statistically significant). Both snow melt and total annual precipitation were most important drivers of DON leaching. IP I and IP II showed comparable temporal patterns of both concentrations and flux rates but exhibited differences in magnitudes: DON, NO ₃ ^? , and NH ₄ ⁺ inputs peak in spring, NH ₄ ⁺ showed an additional peak in autumn; the bulk of the annual NO ₃ ^? and DON output occurred in spring; DON, NO ₃ ^? , and NH ₄ ⁺ output rates during winter months were low. The high DIN leaching at IP I was related to snow cover effects on N mineralization and soil hydrology. From the year 2004 onwards, disproportional NO ₃ ^? leaching occurred at both plots. This was possibly caused by the exceptionally dry year 2003 and a small-scale bark beetle infestation (at IP I), in addition to snow cover effects. This study shows that both forest ecosystems at Zöbelboden are still N limited. N leaching pulses, particularly during spring, dictate not only annual but also the long-term N budgets. The overall magnitude of N leaching to the karst aquifer differs substantially between forest and soil types, which are found in close proximity in the karstified areas of the Northern Limestone Alps in Austria.     

森林土壤氧化亚氮排放对氮输入的响应研究进展

大气中氧化亚氮（N2O）浓度的上升加剧了全球变暖。森林土壤在调节大气N2O浓度中发挥着至关重要的作用。近年来,氮（N）输入对森林土壤N2O通量的影响备受关注。然而,森林土壤N2O排放对N输入响应的机制,尤其是植物和微生物对N2O通量的调控作用尚缺乏系统研究。因此,本文综述了N输入如何通过森林植被（根系N吸收、凋落物分解和形成丛枝菌根）和土壤微生物（微生物量和群落组成）调控N2O产生途径从而影响森林土壤N2O排放。结果表明,植物的竞争性氮吸收能降低氮输入对N2O排放的促进作用,其作用大小可能主要取决于土壤“氮饱和”状态。植物凋落物主要通过分解过程中的养分归还和次生代谢产物释放来影响氮输入背景下的森林土壤N2O排放,前者具有促进作用,而后者具有抑制作用。丛枝菌根主要通过吸收有效氮和水分、促进团聚体形成以及改变N2O相关功能基因群落调控森林土壤N2O通量。N输入导致的土壤酸化或养分限制,通常会降低微生物量和/或改变微生物群落组成,从而控制N2O排放。N输入对N2O不同产生途径也会造成影响,受土壤湿度、N2O底物浓度以及N2O相关功能基因丰度（AOB、 AOA、nirK、 nirS和nosZ）的调控。未来在模型预测中,需要将植物氮吸收、凋落物分解、菌根以及N2O产生途径充分纳入模型,以提高模型预测准确性,为全球变化背景下制订森林管理政策和温室气体减排措施提供支持。     

Changes in Labile and Microbial Pools of Carbon and Nitrogen in Forest Litter Samples under Different Methods of Storage

Eurasian Soil Science - The influence of conservation procedures (drying, freezing, and storage at low positive temperatures) and preliminary aerobic incubation on the result of determination of...     

Impacts from Deposition on Swedish Forest Ecosystems Identified by Integrated Monitoring

Integrated monitoring of ecosystems (IM) is an international co-operative programme (ICP) to control effects of air pollution and climate change on water, soil and biological systems. It is a part of the Convention on Long-Range Transboundary Air Pollution (CLRTAP) of the United Nations Economic Commission of Europe (UN/ECE). The ICP-IM is undertaken on sites/catchments to investigate acidification, eutrophication and heavy metals with an integrated approach. In Sweden, long-term time series from forest ecosystems, with a long and stable continuity, will reveal trends and changes in processes and enable modelling to be undertaken. Investigations of acidity/alkalinity in relation to mineral and organic acids indicated the importance of atmospheric deposition. Recent results show very high inorganic nitrogen retention (99%), a net loss of sulphur originating mainly from organic horizons, and a high inorganic aluminium content in the illuvial soil horizons which could be detrimental to forests. Forest deficiency could also be caused by an observed ongoing translocation of Zn to deeper soil layers implying a movement towards increased release to surface waters.     

山西省油松林生态系统碳氮磷化学计量特征

为了评价山西省油松林生态系统的生态化学计量特征,以山西省油松人工幼龄林(AY)、人工中龄林(AM)、天然幼龄林(NY)和天然中龄林(NM)为研究对象,通过38块标准地实测数据,探讨了4种森林类型的化学计量特征。结果显示:1)AY,AM,NY和NM乔木叶片的C∶N∶P分别为276∶8∶1,283∶8∶1,458∶12∶1和362∶11∶1,灌木叶片的C∶N∶P分别为181∶11∶1,132∶8∶1,228∶9∶1和221∶15∶1,草本叶片的C∶N∶P分别为211∶8∶1,200∶9∶1,190∶8∶1和230∶11∶1,凋落物的C∶N∶P分别为347∶3∶1,246∶5∶1,507∶9∶1和327∶9∶1,土壤(0—100cm)的C∶N∶P分别为23∶6∶1,37∶7∶1,28∶6∶1和30∶5∶1;2)4种类型的C∶N和C∶P基本都表现为凋落物叶片土壤,凋落物和叶片的C∶N和C∶P表现为AYAM,NYNM,土壤的C∶N和C∶P则为AMAY,NMNY,而N∶P则表现为叶片凋落物土壤,在林龄上表现规律不明显,植物叶片N∶P14,存在N限制;3)4种类型植物叶片C∶P均表现为乔木叶片草本叶片灌木叶片,表明油松林生态系统中乔木叶建成效率最高,而灌木叶建成效率最低;4)4种类型土壤层随着土层厚度的增加,C∶N表现出下降规律,C∶P和N∶P规律表现不明显。研究结果表明,4种生态系统的叶片、凋落物和土壤的化学计量特征具有一致性。     

Carbon Fluxes from Different Pools in a Mined Area under Reclamation in Minas Gerais State,Brazil

Despite the benefits of grass cultivation and organic fertilization in mining areas undergoing reclamation, these practices may be associated to CO₂ emissions and soil organic matter (SOM) losses by priming effect. In the present study, we evaluated the changes on SOM pools and C–CO₂ emissions in a bauxite‐mined area under reclamation fertilized with poultry litter (PL) (0, 10, 20, and 40 Mg ha⁻¹) and cultivated with Brachiaria brizantha . Increases of about 3·5 times in the soil labile C were observed 1 year after experiment establishment. High C–CO₂ fluxes and a significant positive priming effect were observed in the presence of B. brizantha , increasing native C mineralization by nearly 4·9 times. Nevertheless, no net soil C loss was detected, probably because of the C inputs derived from B. brizantha , which offset these losses. In fact, the grass increased total organic C by 45% when fertilized with 40 Mg PL ha⁻¹. The data obtained suggest that the cultivation of B. brizantha fertilized with PL can be a promising option for rapid recovery in SOM in areas under reclamation. Copyright © 2016 John Wiley & Sons, Ltd.     

林地开垦后对不同质地红壤碳氮和磷库的影响

林地开垦农用后,土壤有机C和总N、P的浓度及在各团聚体粒级中的分布可发生较大的变化。对亚热带山地两类不同质地的红壤研究表明,林地开垦为旱地和茶园后,有机质和全N明显下降,全P呈轻微下降。下降量壤质土壤(黄泥土)大于粘质土壤(黄粘泥)。表土(0～15cm)的有机C和总N、P下降大于亚表土(15～30cm)。在三个团聚体粒级中,砂粒中有机C和总N、P的下降幅度最大,并随粒径变细下降幅度逐渐变小,表明与砂粒和粉砂结合的有机C和N、P易受利用方式的改变而变化。从林地到茶园、旱地,各团聚体粒级中有机P及有机P占总P的比例趋向下降。砂粒和粉砂中Olsen-P也呈下降的趋势。     

Atmospheric Mercury Fluxes in a Southern Boreal Forest and Wetland

Total gaseous mercury (TGM) fluxes from the forest floor and a boreal wetland were measured by a flux chamber technique coupled with an automatic mercury vapour analyser. The fluxes were measured at three sampling sites in southern Finland, 61°14′ N, 25°04′ E in summer 2007, with additionally in situ TGM concentrations in the air at one of the sites and mercury bulk deposition at another. Most of the flux data were collected during the daytime. At one of the sites, diurnal flux behaviour was studied, and a clear cycle with an afternoon maximum and a night minimum was observed. The highest emissions (up to 3.5 ng m⁻² h⁻¹) were observed at the forest floor site having a moss and grass cover. At the wetland and litter-rich forest floor sites, the emissions were below 1 ng m⁻² h⁻¹ and sometimes negative (down to −1.0 ng m⁻² h⁻¹), indicating mercury uptake. The measured average fluxes in August were 0.9 ± 1.1 and 0.2 ± 0.3 ng m⁻² h⁻¹ for the forest floor sites and wetland sites, respectively. The flux data were compared with the mercury bulk deposition, which proved to be of the same magnitude, but opposite in sign. At the mossy forest floor site, the extrapolated TGM emissions were 130% of the Hg deposition in August 2007. Comparison with other studies showed that the fluxes in background areas are relatively uniform, regardless of measurement site location and method used. Airborne TGM remained at the background level during the study, with an average value of 1.3 ± 0.2 ng m⁻³; it frequently showed a diurnal cycle pattern.     

广西喀斯特次生林地表碳库和养分库特征及季节动态

以自然保护区原生林为对照,调查了广西喀斯特区处于同一次生演替序列中的灌丛、藤刺灌丛、乔灌丛3个群落的地表凋落物存量,同时对凋落物层和土壤表层(0-5 cm)的有机碳,全氮、磷、钾等养分元素的含量、贮量状态及其雨季前后的变化进行了研究.结果表明:地表凋落物存量及有机碳、全氮贮量随演替阶段上升均呈增高趋势;除全磷外,土壤的有机碳和养分元素含量与凋落物层贮量相关性显著(p<0.05);雨季期间,凋落物迅速分解,地表凋落物的分解量要大于当季凋落量,并且次生林的凋落物分解与养分释放量显著高于原生林;雨季后,各群落有机碳和养分的凋落物层贮量以及土壤含量均有所降低.其中凋落物层贮量下降显著的是藤刺灌丛与乔灌丛.土壤养分含量则在灌丛与原生林阶段下降更为明显.在从灌丛向顶级群落演替的进程中,森林的自养能力可能存在一个先增高再降低的过程.     

Critical Loads of Acidity for Forest Ecosystems of North Asia

Critical loads of acidity were calculated using the PROFILE model to assess the forest ecosystem sensitivity to acid deposition in the Asian part of Russia — Siberia. The main input parameters and the output were mapped. At present atmospheric inputs of acid forming pollutants to the study territory are mainly related to transregional and transboundary pollution from Europe. It was shown that the most sensitive to acid loading are ecosystems of the Tundra zone and of the East Sayan mountains' coniferous forests with dystric cambisols and gleysoils, critical loads of actual acidity (CL(Ac)) = 0–0.3 keq/ha/yr. The most tolerant ecosystems are ecosystems of deciduous forests with podsoluvisols, luvisols and humic luvisols of South Taiga zone in West Siberia, CL(Ac) = 3.5–7.0 keq/ha/yr. Generally the values of critical loads are increasing from the North to the South and from the East to the West following the bioproductivity, annual soil temperature and alkalinity of deposition increases.     

Transformation of Forest Ecosystems in Moscow Megapolis under Recreational Impacts

Eurasian Soil Science - A comprehensive quantitative assessment of the state of vegetation, soil invertebrate complex, litter horizons, and soddy-podzolic soils (Albic Retisols) in Moscow forest...     

大兴安岭北部森林生态系统土壤动物组成与多样性分析

对大兴安岭北部7个代表性森林群落土壤动物进行调查,共捕获湿生土壤动物20216只,大、中小型土壤动物87类,19577只,隶属于4门9纲23目66科。大、中小型土壤动物的优势类群为螨类和节跳虫科,常见类群4类,两者占总捕获量的92.22%。各群落土壤动物的数量和种类组成有一定差异,其中杨落Ⅱ和白桦Ⅲ的数量和种类最多,柳草Ⅶ最少。7个群落共有类群23类,共优类群为螨类中的前气门亚目和中气门亚目,共有的常见类群2类:山跳虫科和线蚓科。7个群落间相似程度均较大,大多为中等相似。各群落土壤动物数量和种类在土壤各层的垂直分布上具有明显表聚性。在多样性分析中,各群落多样性指数H′大小为柳草Ⅶ>白桦Ⅲ>杨落Ⅱ>落沼Ⅳ>樟子松Ⅵ>桦杜Ⅰ>蒙古栎Ⅴ。大部分群落多样性指数的动态变化是8月>6月>10月。     

Bacterial Diversity in Peat Soils of Forest Ecosystems and Oil Palm Plantation

Eurasian Soil Science - Bacteria play a crucial role in regulating biogeochemical cycles in peatlands. Most of the studies on soil bacteria focus mainly on the peat surface and bacteria that exist...     

亚热带区域几种典型人工林生态系统林地土壤质量评价

针对不同经营模式对林地土壤的物理性质、化学性质和生物学性质的影响,采用主成分分析方法直观定量地研究了亚热带区域几种典型人工林生态系统林地的土壤质量指数和土壤退化指数,揭示了土壤质量指数之间的相关性和差异性、以及土壤退化指数之间的相关性和差异性,并很好地识别出了土壤质量指数和土壤退化指数的主要成分。分析结果基本上反映了不同生态类型林地土壤质量状况,主成分分析土壤质量指数得分以常绿阔叶林最高,其次是混交林和阔叶纯林,连栽杉木纯林最低;主成分分析土壤退化指数表明,与次生常绿阔叶林比较,其中连栽杉木纯林退化幅度最大,而混交林和阔叶纯林次之。从而对其林地土壤质量进行了准确评价,为杉木人工林的可持续利用提供直接依据,并为亚热带区域人工林生态系统林地土壤质量评价提供参考。     

长江三角洲地区竹林经营中的氮磷流失负荷概算

通过分析长江三角洲地区竹林集约经营面积、竹林施肥情况及氮(N)、磷(P)流失率,对该区竹林经营中因施肥产生的N、P流失量进行了概算.结果表明,长江三角洲地区竹林中每年N、P流失量分别为3795～6067t、828～1104t.其中,浙江省竹林地的N、P流失量分别为3573～5713 t、779～1039 t,均占总流失量的94%.从单位面积上的流失量来看,浙江省竹林地N流失负荷(9.8～15.6kg/hm2)显著低于该省农田N流失负荷(57.4 kg,hm2),而P流失负荷(2.1～2.8 kg/hm2)稍高于农田(1.7 kg/hm2) .在部分高度集约经营地区,竹林地每年的N、P流失更高.这些竹林地主要位于水源上游或河湖两岸,流失的N、P进入水体后,将对水体造成污染,降低水质,加速下游水体的富营养化.     

北京市森林生态系统土壤保持能力的综合评价

为客观认识北京市森林生态系统的土壤保持功能,选用植被覆盖度、枯枝落叶厚度、林分类型、郁闭度和群落结构等5项指标,综合评价了北京市森林土壤保持能力的相对大小.结果表明:北京市森林生态系统的土壤保持能力较高,其中65.7%的森林保持土壤能力为中等以上,16.8%的森林保持土壤能力较低;不同区县森林的保土能力存在差异,其中石景山区的森林保土能力最高,其次为延庆县、密云县和门头沟区,而大兴区森林的保土能力最低;随着海拔高度增加,森林保持土壤的能力升高,即中山区(海拔＞800 m)森林的保持土壤能力最大,而平原区(海拔＜100 m)森林保持土壤能力较低;地形坡度增大,森林保持土壤能力也增加,不过坡度25°以上森林的保土能力接近;林地土壤类型不同,森林保持土壤能力也不同.其中土壤类型为山地棕壤、山地草甸土和褐土的森林保土能力较高,而为水稻土、潮土、风砂土和草甸沼泽土的森林保土能力较低.     

Nitrogen Fluxes of a Slope Mire in the German Harz Mountains

Nitrogen (N) fluxes of a slope mire in the German Harz Mountains were monitored to study the effect of increased N deposition on the N retention of the mire. In addition, the N content of mire pore water beneath different plant species was analyzed to assess N retention ability of plants. Atmospheric N deposition at the study site was 4.9?±?0.4 g N m^?2 year^?1 averaged for the study period of 2002 and 2003, with forest stand deposition being the largest share. Discharge was the main output pathway of N with a rate of 1.9?±?0.3 g N m^?2 year^?1. The mire showed a high N retention rate of 67%. Short-term N accumulation rate was 3.9 g N m^?2 year^?1. Differences in mire pore water N concentration under different vegetation cover indicate a lower N retention ability for ombrotrophic Sphagnum plants.     

北京山区典型森林生态系统土壤水文特征研究

对北京山区4种典型森林生态系统的土壤水文特征进行了研究。结果表明,除侧柏外,研究区各林分土壤容重都随土层深度增加而增加,土壤总孔隙度和毛管空隙度都随土层深度增加而减小,而非毛管空隙度变化没有普遍规律性。不同林分各层次土壤水势都随土壤含水率的增加而降低,100kPa为土壤水分特征曲线的临界值。土壤入渗的瞬变阶段发生在0～5min,渐变阶段发生在5～60min,稳定阶段发生在60min以后,针叶林的土壤渗透能力要明显高于阔叶林。用双环入渗法得出的土壤入渗过程用蒋定生公式拟合的效果最佳。     

青海湖2种高寒嵩草湿草甸湿地生态系统水热通量比较

基于涡度相关技术,研究了2015年青海湖2种高寒嵩草湿草甸湿地生态系统水热通量的特征。结果表明:(1)2015年青海湖高寒藏嵩草和小嵩草湿草甸湿地生态系统日平均水汽通量分别为1.74,0.99mm,年水汽通量分别为633.3,362.1mm。(2)青海湖2种高寒嵩草湿草甸湿地生态系统感热、潜热和净辐射日变化均呈单峰曲线,感热和潜热月平均日变化最大值出现的时间均晚于净辐射。藏嵩草湿草甸湿地生态系统感热月均日变化最大值最大为179.06W/m~2,最小为46.02W/m~2;潜热最大为312.55W/m~2,最小为30.58 W/m~2;小嵩草湿草甸湿地生态系统感热月均日变化最大值最大为161.86 W/m~2,最小为31.60 W/m~2;潜热最大为215.44 W/m~2;最小为14.08 W/m~2。(3)通过波文比分析发现,2种高寒嵩草湿草甸湿地生态系统生长季能量分配以潜热为主,非生长季小嵩草湿草甸湿地生态系统能量分配以感热为主,藏嵩草湿草甸湿地生态系统则较为复杂。藏嵩草湿草甸湿地生态系统全年能量平衡率为0.82,小嵩草湿草甸湿地生态系统为0.89,增加土壤热通量项能改善能量平衡状况。