杉木林乔木层凋落物及其在分解过程中化学成分的变化

广西龙胜县里骆林区24～28年生杉木的凋落物产量为3.749t/ha·a,其中落叶、落枝和落花果分别占55.9％,23.1％和21.0％。通过凋落物归还土壤的10种营养元素的总量,以kg/ha·a表示,为65.500,其中N 21.726,P 1.206,K 6.838,Ca 24.805,Mg 6.224,S 2.030,Mn 2.545,Zn 0.075,Cu 0.021,B 0.030。用指数衰减模型估算的凋落物分解速率为:叶子0.4988g/g·a,枝0.4154g/g·a,花果0.4166g/g·a。在分解过程中,各元素含量与分解初期相比,K的含量下降了,失重量的比率大于凋落物的;N,P,Ca,Mg,Mn,Cu的含量上升了,失重量的比率小于凋落物的;S,Zn和B的含量变化不大,失重量比率与凋落物的相当。     

两类森林凋落物及其分解作用的研究

根据1984～1989年的定位观测,广西岑溪县七坪林场常绿阔叶林的凋落物量平均为8.062t/ha·a,N,P,K,Ca,Mg,S,Mn,Cu,Zn 9种营养元素的归还量平均为209.47kg/ha·a,分别比杉木林的高1.82倍和2.08倍。常绿阔叶林凋落物各组分的平均分解速率(g/g·a)为:叶1.0842,枝0.6502,果0.8871;而杉木林的分别为0.6084,0.3795和0.5255。表明常绿阔叶林在提高林地土壤肥力方面大于杉木林。     

里骆林区杉木成熟林降雨的养分含量

本文报道广西龙胜县里骆林区24～28年生杉木林林内和林外降水的养分含量及其变化。林外雨的元素含量,以kg/ha·a表示,N是12.972,P 0.289,K 7.249,Ca 9.154,Mg 3.676。乔木层的元素淋溶量,以kg/ha·a表示,N是10.715,P 0.249,K 9.420,Ca 8.675,Mg 9.574。N,P,K的淋溶量与它们在杉木冠层中的积累量呈直线相关;K,Ca,Mg的淋溶量与林内降水量呈直线相关。降水淋溶是K和Mg归还的主要途径。     

刚果桉人工林营养元素生物循环研究

对刚果12号桉无性系W5人工林营养元素积累、分布和生物循环进行了研究。结果表明,刚果桉W5不同组分的营养元素含量存在差异。树叶的主要营养元素N、P、K、Ca、Mg含量均较高,树皮的Ca、K含量较高,树干主要营养元素的含量均较低;刚果桉W5人工林主要营养元素年净积累量随林龄增长而增加,2年生的主要营养元素净积累量的增幅最大;刚果桉W5人工林的N、K或Ca的年吸收量与总存留量较高,Mg次之,P最小。植后第5年,Ca的吸收与存留增加明显;刚果桉W5人工林归还林地的主要营养元素比例很低,2～5年生林木以凋落物形式归还的营养元素在12％～15％,其中N、Mg的归还率在20％以上,Ca的在8%～14％,P的在6．5％～9％,K的不足5％。与热带半落叶季雨林比较,刚果桉W5人工林的养分循环率要小得多,说明这一人工林土壤养分趋向于减少。     

太行山地区侧柏人工林主要养分元素分配及循环特征

为了解侧柏(Platycladus orientalis)人工林养分循环特征,以太行山丘陵区侧柏人工林为研究对象,采用样地标准木收获法,对其生物量和养分循环进行了研究.结果表明:(1)侧柏人工林(26 a)生物量约45.55t/hm2,林分净生产力为2.07 t/hm2;生物量分配排序为;树干树根树皮树枝树叶.(2)林分营养元素积累量为455.23 kg/hm2,积累量的排序为:CaNP.(3)灌草植被层营养元素积累量顺序为:CaNP,灌草层3种元素总贮量仅占乔木层的5.5%.(4)凋落物营养元素年归还量为337.12 kg/hm2,3种营养元素归还量排序为:CaNP,Ca的年归还量最高,为271.66 kg/hm2,分别是N和P的4.42倍和69.12倍.(5)年吸收量、年存留量、养分年归还量和富集系数排序均为CaNP;吸收系数排序为CaNP;利用系数、循环系数排序是NCaP,侧柏对N的利用系数最大;Ca的富集能力最强.分别是N,P的1.9和2.8倍.侧柏的N周转时间最短(1.22 a),P周转时间最长(3.63 a),Ca周转时间居中(1.43 a).     

马占相思近熟林养分循环研究

研究了广西高峰林场11年生（近熟林）马占相思人工林10种营养元素生物循环的特点。结果表明：（1）马占相思不同器官营养元素含量以树叶（叶状柄）为最高,树干最低;各器官中大量营养元素含量以N最高,其次是Ca或K,然后是Mg,P最低;微量元素含量则以Mn和Fe最高,其次是Zn和B,Cu最低;（2）林分营养元素贮存量为2609．28kg／hm^2,乔木层、灌木层、草本层和凋落物层分别占83．95％、4．43％、1．71％和9．91％,林木中不同器官营养元素贮存量排序为干材〉树枝〉树根〉干皮〉树叶．（3）林分年吸收量、归还量、存留量分别为388．47、195．51和192．96kg／（hm^2·a）,10种元素的循环系数为0．39～0．78,循环速率依次为Mn〉Zn〉Mg〉P〉Ca〉Fe〉N〉Cu〉K〉B。     

太行山丘陵区刺槐人工林主要养分元素分配及循环特征

为了解刺槐人工林养分循环特征,以太行山丘陵区刺槐人工林为研究对象,采用样地标准木收获法,对其生物量和养分循环进行研究。结果表明：1）刺槐林乔木层总生物量为39.87 t/hm^2,各器官生物量排序为树干〉树根〉树皮〉树枝〉树叶,树干所占生物量比例最大,叶生物量最小。2）3种元素在各器官中含量表现出较大差异,在树干、树根和树皮中的含量大小排序是N〉Ca〉P,枝、叶中含量排序为Ca〉N〉P。3）各器官营养元素积累量、年存留量分配关系为树干〉树叶〉树枝〉树根〉树皮,林分3种营养元素积累量为633.20 kg/hm^2,积累量和年存留量大小排序为Ca〉N〉P,Ca积累量最多（368.36 kg/hm^2）,P最少（18.19 kg/hm^2）,N居中（276.65 kg/hm^2）。4）凋落物营养元素年归还量为286.52 kg/hm^2,3种营养元素年归还量大小排序为Ca〉N〉P,Ca最高（196.48 kg/hm^2）,分别是N和P的2.31倍和40.26倍。5）刺槐人工林吸收系数排序为N〉P〉Ca,富集系数为N〉P〉Ca,刺槐对N吸收系数、富集系数均高于P、Ca,利用系数、循环系数排序是Ca〉N〉P,Ca周转时间最短（1.87 a）,P最长（3.73 a）,N居中（3.25 a）。     

北京密云油松人工林凋落物营养元素归还特征研究

2006-2007年对北京密云水库库西33年生的油松人工林凋落物的数量及其营养元素归还特征进行了研究。结果表明,油松人工林凋落物年凋落量为2193.75kg/hm2;N、P、K通过凋落物归还土壤的年归还量分别为13.86,0.75,3.39kg/hm2;油松凋落物各组分中N、P、K归还总量大小顺序为:叶枝皮、果、花;N、P、K年归还量大小顺序为:NKP。凋落物现存量为13.7t/hm2,凋落层年平均分解率为0.16t/hm2,凋落物层N、P、K总贮量为162.44kg/hm2。     

氮沉降对杉木人工林凋落物大量元素归还量的影响

通过野外模拟试验,研究了杉木人工林(Cunninghamia lanceolata)凋落物养分归还对氮沉降增加的响应。试验设计为4种处理,分N0(对照)、N1、N2、N3共4种处理,N沉降量分别为0,60,120,240kg N/(hm2.a)。每处理重复3次。通过3a监测发现,经N0、N1、N2、N3处理,N元素平均年归还量分别为8.49,8.51,9.57,9.37kg/hm2,P分别为0.74,0.68,0.73,0.72kg/hm2,K分别为3.57,3.93,4.02,3.98kg/hm2,Ca分别为6.81,6.96,6.76,7.12kg/hm2,Mg分别为2.12,2.22,2.08,2.30kg/hm2,相对于N0处理,各水平的氮沉降处理在3a时间里表现为提高凋落物N归还量的作用,但是增长幅度有下降的趋势,对P元素归还有抑制作用,对K、Ca、Mg元素先期表现为促进其归还量的作用,但在后期逐渐有呈抑制的趋势。各处理凋落物5种元素归还量均在2,4,7月出现3个明显的归还高峰期,最大值均出现在7月份。     

太行山丘陵区不同龄级栓皮栎人工林养分循环特征

为定量分析植被恢复进程的变化特征,以太行山丘陵区的栓皮栎人工林为研究对象,在样方调查的基础上,对其各器官N、P、Ca 3种营养元素的含量、积累、分配和养分循环变化情况进行研究。结果表明：1）不同植物器官中,营养元素含量差异明显;各龄级中,营养元素含量最多的器官是树叶,树干含量最低;营养元素含量的排序为Ca〉N〉P。2）林地土壤有机质、N和P含量随龄级增加呈明显增长趋势,植被恢复能明显加快土壤肥力的提高。3）20-40 a栓皮栎人工林营养元素积累量为2764.58-3689.38 kg/hm^2,年存留量为89.88-138.17 kg/（hm^2·a）,归还量为229.80-262.06 kg/（hm^2·a）。随龄级增加,营养元素储存总量随之升高,而存留量反而降低;吸收量和归还量呈现先升高后降低的趋势;不同营养元素的储存量、吸收量、归还量和存留量的大小排列次序均为Ca〉N〉P。4）循环系数和周转时间随龄级增加而升高,利用系数则呈现下降趋势;各元素之间Ca的周转时间最长（12.73-16.19a）,利用系数最小。     

我国南亚热带几种人工林的生物物质循环特点及其对土壤的影响

通过对杉木、马尾松、红荷木、格木四种人工林的三年定位研究,初步获得了四种林木对主要营养元素的生物吸收和归还特点、对土壤养分状况、水分状况、微生物状况和土壤酶活性的影响等一系列资料。初步阐明了四种林木凋落物的数量及主要营养元素含量,研究了四种林木凋落物的分解特点。从而为进一步研究林木混交提供了科学依据。研究表明,阔叶树种与针叶树种相比,在改善土壤理化性状、提高土壤生产力等方面都表现出明显的优点。     

The Transfer of Chemical Elements within a Heath-Ecosystem (Calluna vulgaris) in Northwest Germany

The purpose of this investigation was to describe the element budget of a heathland area in Northwest Germany by measuring the fluxes of elements within the ecosystem. The following fluxes were considered: input by precipitation, canopy-drip, mineralisation, ion uptake, litterfall, output with seepage water. The elements H, Na, K, Ca, Mg, Mn, Fe, Al, S, P, CI, NO, NH, N_org were analysed, the period of investigation was one year. The results demonstrate the high importance of deposited nutrients like N (especially No3), Ca and Mg for the element budget and the stability of a heath-ecosystem. The internal turnover of K, Ca, Mg and Mn within the ecosystem mainly took place by leaching. No leaching was found for N, P, AI, Fe, S, CI, Na. For these elements litterfall was the dominant internal way of cycling. The humus layer was a sink for total-N, NO, Ca, Mg, Mn, Fe and S. NO, Ca, Mg, Mn and S were removed from the percolating solution, while for Fe and especially N and Mn an inhibition of mineralisation was found. The element balance for the mineral soil showed that this part is a sink for Hand a source mainly for Al, Ca and Mg, less for K and Na. From the cation/anion balance of the storage changes in mineral soil the ecosystem-internal H ion production was calculated as 0.4 keq per ha and year. It may be traced back to an uptake of NH, and dissociation of fulvic acids in the mineral soil. The results are discussed with respect to the development, stability and management of heath-ecosystems.     

猫儿山自然保护区不同林分类型土壤生态化学计量特征

  目的  为揭示猫儿山自然保护区不同林分下的土壤有机碳（C）、全氮（N）、全磷（P）、全钾（K）含量与化学计量比之间的相关性及其变化特点。  方法  采用野外调查采样与室内实验分析相结合的方法,测定水青冈林、毛竹林、杉木林3种林分类型的不同深度土层土壤有机C、全N、全P、全K养分含量,计算其化学计量比,并用多重比较和相关性分析方法综合评价土壤生态化学计量特征。  结果  不同林分类型土壤养分含量与生态化学计量比都存在显著差异(P < 0.05)。土壤有机C、全N含量在林分和土层间差异显著(P < 0.05),在同一林分下随土层深度增加而降低。土壤有机C、全N含量在3种林分间表现为水青冈 > 毛竹 > 杉木,即以水青冈林分最大,其平均值分别达55.91 g kg?1和4.20 g kg?1;全P、全K含量在林分间、土层间存在差异,但未达显著水平;而不同养分含量比C/N、C/P、C/K、N/P、N/K、P/K整体变化相似,在林分间排列顺序为水青冈 > 毛竹 > 杉木。相关分析结果表明,土壤有机C与全N、全P与全K间分别呈极显著(P < 0.01)和显著正相关关系(P < 0.05),而全P与有机C、全N均无显著相关性,全K与有机C、全N呈显著负相关关系。  结论  水青冈天然次生林分土壤有机C、全N高于毛竹人工林、杉木人工林两林分,有较好的养分归还及地力维持效果。     

长白山红松阔叶林的生物养分循环

本文对东北长白山红松阔叶林的生物量,营养元素分布和养分循环进行研究,结果表明:该地每公顷生物量约为211吨,其中地上部分生物量占82%,地下部分占18%,而年生产量每公顷为7.087吨.该林分地上部分生物量的氮、磷、钾、钙和镁分别为每公顷618.6、56.47、511.82、1057.95和75.85公斤,而年生物量的氮、磷、钾、钙和镁分别为每公顷78.58、7.72、45.80、84.51和13.97公斤.凋落物在养分循环中起着重要作用,在从土壤年吸收的养分中,大量养分通个凋落物又归还土壤.通过计算看出,生产1吨乔木生物量,红松需要消耗氮、磷、钾、钙和镁分别约为9、1、3、4及1公斤,而阔叶树需要消耗上述养分分别约为16、1、9、17及4公斤.     

Release and retention patterns of organic compounds and nutrients after the cold period in foliar litterfall of pure European larch,common beech and red oak plantations in Lithuania

This study was carried out in alien warmth-tolerant forest plantations of red oak (Quercus rubra), common beech (Fagus sylvatica) and European larch (Larix decidua). We compared the changes in foliar litterfall mass and biochemical composition after five months of cold period. The mean mass of fresh foliar litterfall collected in late autumn was 30% higher in red oak compared to the larch and beech plantations. After the cold period, the reduction of foliar litterfall mass did not exceed 10% in any of the studied plantations. The fresh foliar litterfall of red oak was the richest in cellular fibre and easily decomposable glucose and nutrients such as P and Mg, larch was distinguished by the highest lignin, N, K and Ca concentrations, while beech fresh foliar litterfall was the poorest in the aforementioned nutrients. After the cold period, the changes in the biochemical composition of foliar litterfall revealed different patterns. In the spring, the beech and red oak foliar litterfall was the richest in N, P and Ca, meanwhile the larch foliar litterfall still had the highest concentration of lignin but, in contrast to the autumn, was the poorest in nutrients. After the cold period Lignin: N, C: N and C: P ratios reached critical values indicating that the foliar litterfall of beech and red oak had started to decompose. The highest lignin concentration and the highest and most stable Lignin: N, C: N, C: P and N: P ratios after the cold period indicated that the slowest foliar litterfall decomposition took place in the larch plantation.     

密云水库北京集水区油松水源保护林主要养分元素积累与分配研究

对密云水库北京集水区油松水源保护林主要养分元素积累与分配的研究结果表明:29年生油松林的生物量为92 627 kg/hm².油松林不同器官中各养分元素的含量差异较大,在叶、枝和干中各养分元素的含量顺序分别为N(K)>K(N、Ca)>Ca(K)>Mg(P)>P(Mg).根系中的养分元素随着根系直径的增加呈各养分元素的含量降低.油松林生态系统5种养分元素的贮存量为695.17 kg/hm².若以各养分元素在油松林生态系统中的贮存量来计,则N的贮存量最大,P的最小,不同养分元素贮存量的顺序N>Ca>K>Mg>P.油松林生态系统对N元素的富集能力最强,不同器官中各养分元素的富集系数排序均为N>P>K>Ca>Mg.油松林每积累1 t干物质需N、P、K、Ca和Mg等5种养分元素共计7.51 kg.     

氮、磷肥对杉木幼苗生物量及养分分配的影响

采用盆栽试验,研究了不同氮、 磷肥对杉木（Cunninghamia lanceolata）幼苗生物量及养分分配的影响。结果表明,供磷可促进杉木幼苗植株和各器官生物量的增加,并影响叶、 茎、 根生物量的分配比例,氮、 磷处理幼苗叶生物量占全株生物量的45% 以上, 施氮反而降低杉木叶、 茎、 根的生物量; 施氮显著增加根和叶的氮含量,而显著降低根和叶的磷含量,对茎的氮、 磷含量没有明显影响; 施磷显著降低叶、 茎、 根的氮含量,叶、 茎、 根的磷含量随供磷水平的增加而逐渐增加。氮磷配施显著影响叶、 茎、 根的氮、 磷含量和氮、 磷累积量。叶片是主要的氮、 磷养分存储器官。氮（或磷）水平的增加可降低杉木幼苗的磷（或氮）利用效率,提高氮（或磷）的利用效率; 氮、 磷肥显著影响杉木幼苗叶、 茎、 根的N/P比。研究结果说明,氮、 磷肥增加了杉木幼苗各器官生物量和氮、 磷含量,影响了幼苗的养分分配和营养平衡。     

红壤侵蚀区不同生态修复措施对凋落物量及其养分归还的影响

通过野外定位监测和取样分析,探讨在红壤侵蚀区采取4种生态修复模式(马尾松林、修沟种草马尾松林、修竹节沟马尾松林和封禁马尾松林)27年后,其林分凋落物量及其养分归还动态。结果表明,4种修复措施林分的年凋落物总量分别为3 267.30,3 530.58,3 937.67,4 997.88kg/hm2,说明封禁处理对于提高林分凋落物量效果显著。各修复措施凋落物量呈现明显的季节动态,全年凋落物呈现单峰型,峰值均出现在8月份。4种修复措施(马尾松林、修沟种草、修竹节沟和封禁)凋落物的5种元素(N、P、K、Ca、Mg)归还总量分别33.83,38.90,48.39,64.40kg/hm2,大小顺序为:封禁>修竹节沟>修沟种草>强干扰马尾林,其中N元素的年通量变化为23.33～47.60kg/hm2,P为0.50～0.96kg/hm2,K为5.40～8.62kg/hm2,Ca为4.02～6.33kg/hm2,Mg为0.58～0.89kg/hm2。     

Substantial net N mineralization during the dormant season in temperate forest soils

In temperate forest soils, N net mineralization has been extensively investigated during the growing season, whereas N cycling during winter was barely addressed. Here, we quantified net ammonification and nitrification during the dormant season by in situ and laboratory incubations in soils of a temperate European beech and a Norway spruce forest. Further, we compared temperature dependency of N net mineralization in in situ field incubations with those from laboratory incubations at controlled temperatures. From November to April, in situ N net mineralization of the organic and upper mineral horizons amounted to 10.9 kg N (ha · 6 months)^–1 in the spruce soil and to 44.3 kg N (ha · 6 months)^–1 in the beech soil, representing 65% (beech) and 26% (spruce) of the annual above ground litterfall. N net mineralization was largest in the Oi/Oe horizon and lowest in the A and EA horizons. Net nitrification in the beech soil [1.5 kg N (ha · 6 months)^–1] was less than in the spruce soil [5.9 kg N (ha · 6 months)^–1]. In the range of soil temperatures observed in the field (0–8°C), the temperature dependency of N net mineralization was generally high for both soils and more pronounced in the laboratory incubations than in the in situ incubations. We suggest that homogenization of laboratory samples increased substrate availability and, thus, enhanced the temperature response of N net mineralization. In temperate forest soils, N net mineralization during the dormant season contributes substantially to the annual N cycling, especially in deciduous sites with large amounts of litterfall immediately before the dormant season. High Q₁₀ values of N net mineralization at low temperatures suggest a huge effect of future increasing winter temperature on the N cycle in temperate forests.     

Impact of N and P fertilizer application on nutrient cycling in jarrah (<Emphasis Type="Italic">Eucalyptus marginata</Emphasis>) forests of south western Australia

Jarrah (Eucalyptus marginata Donn ex Smith) forest grows on poor soils with low stores of plant-available nutrients. We evaluated the impact of fertilizers on nutrient cycling in soil under Jarrah forest using a field study with three rates of P (0, 50, 200 kg P ha^–1) and three rates of N (0, 100, 200 kg N ha^–1) in a full factorial design. Litterfall was significantly increased by N application (30% relative to controls) in the first 2 years after treatment and by P application in the second year. The amounts of N, P, K, Ca and Mg in litterfall were also increased significantly by both N and P fertilizer. Although fertilizer treatments did not affect the total amount of litter accumulated on the forest floor over 4–5 years after application, there were large treatment differences in the amounts of N and P stored in the forest floor. Microbial respiration in litter was significantly greater (19%) on P-treated plots relative to controls, but this increase did not translate into increased decomposition rates as measured in long-term (5-year) mesh-bag studies. The results indicate that factors other than nutrition are mainly responsible for controlling the rate of decomposition in this ecosystem. Application of P, in particular, resulted in substantial accumulation of P in forest floor litter over 5 years. This accumulation was partly a result of the deposition of P in litterfall, but was also probably a result of translocation of P from the mineral soil. During the 5-year decomposition study, there was no net release of P from leaf litter and, at the highest rate of P application, the amounts of P stored in forest floor litter were more than four-fold greater than in fresh litter. Regular fire, a common phenomenon in these ecosystems, may be an important P-mobilizing agent for enhancing plant P uptake in these forests.