毛乌素沙地羊柴人工林生物量特征及固碳能力研究

为了巩固和提升沙地生态系统的碳汇能力,本研究选择毛乌素沙地羊柴(Corethroden‐dron fruticosum)人工林为研究对象,分析了不同林龄羊柴人工林的植被层、枯落物层、土壤层的生物量及碳密度特征。结果显示:羊柴地上生物量从8 a生到17 a生增加了1.76倍,而草本层生物量、枯落物层生物量差异不显著。羊柴的平均碳含量为48.11%,草本层的平均碳含量为42.83%,枯落物层的碳含量为42.29%。随着林龄增加,羊柴人工林碳密度显著增加(P<0.05),灌木层碳密度增长了175%,草本层增长了6.89%,枯落物层增长了15.12%,土壤有机碳含量增长了16.69%。研究表明,不同林龄的林分生物量存在较大差异,开展不同环境条件、林分结构下植被的生物量及碳密度研究,可为准确估算林分固碳能力提供科学依据。

大宽行桉树人工林混农系统中桉树生物量特征比较研究

采用分层切割法和标准枝法对尾巨桉单株和林分生物量、生物量结构特征和林分生产力进行研究。结果表明:不同种植模式中,桉树的枝、叶量均随着带距的增加而增加;同一种带距中,则随着株距的增大而增大。各种种植模式中桉树树冠与对照相比,均呈现较严重的"偏冠"现象,带外树冠生物量比带内树冠大25.35%～308.45%,但随株距的加大而减小。宽带行桉树的最低枝下高与对照相比,明显偏低,证明宽带行桉树的树冠长度大于对照。桉树平均单株的生物量也随着带距的增加而增加。除8 m带距比对照小2.5%～10.9%,其余模式均大于对照10.2%～23.07%。干材生物量所占比例随带距增大而减小,同种带距随株距增大而减小。林分生物量整体上株距8 m>14 m>16 m>对照;平均比对照分别大42.1%、11.8%、15.7%。从生物量结构特征中可知,14 m和16 m带距的4种模式林分较为稳定。8 m带距的3种种植模式林分差异较大。不同种植模式间桉树的生产力存在明显差异,均随着株行距增大呈增大趋势。其中,8 m带距的种植模式最高,总量比对照高33.42%～56.13%。

闽楠木荷混交幼林生长规律及生物量分布特征研究

以金洞林场14年生闽楠木荷人工混交林为研究对象,采用树干解析和分层收获法对闽楠与木荷的生长规律以及生物量分配特征进行研究。结果表明:1)闽楠与木荷胸径的速生期均为8～12 a,胸径的连年生长量分别在10 a和12 a时达到最大值;2)闽楠与木荷树高的连年生长量分别在第12 a与第10 a时达到最大值,随后急速下降,闽楠树高连年、平均生长量在13 a左右相交;3)0～8 a时,闽楠与木荷的材积生长速度缓慢,8 a以后生长速度上升,14 a时仍处于材积增长的速生期;4)闽楠与木荷单株材积生物量分别为61.43 kg和83.29 kg,各个器官生物量大小顺序均为:树干>树根>树枝>树叶>树皮;5)林分总单位面积生物量为136.29 t·hm^(-2),其中乔木层所占比值高达93.09%,各层次单位面积生物量由大到小排列顺序为:乔木层>半分解枯落物层>未分解枯落物层>草本层。

贵州雷公山甜槠栲群落优势树种生物量研究

为了探索贵州雷公山常绿阔叶林优势树种的生物量特征,在典型植被甜槠栲群落中通过样地调查核实了群落基本特征,并选取常绿优势树种甜槠栲、长蕊杜鹃,采用标准木法研究了其地上部分生物量分配特征及生物量模型。结果表明:雷公山甜槠栲群落内,甜槠栲单木树干、树枝、树叶生物量平均分别为12.96 kg、4.65 kg、2.08 kg,长蕊杜鹃相应生物量分别为15.85 kg、7.77 kg、1.64 kg;生物量分配上,甜槠栲各组分所占地上部分比例大小为:树干(53.21%)>树枝(23.84%)>树叶(12.68%),长蕊杜鹃为:树干(54.79%)>树枝(31.10%)>树叶(10.90%);生物量模型拟合显示,一元模型(W=aDb)与二元模型(W=a(D2H)b)在两树种干、皮、枝、叶各组分生物量拟合中都能满足精度需要,但单木地上部分总生物量的拟合则以二元模型的精度更高。

不同播期和灌水条件下冬小麦生物量变化与产量模拟

为了阐明播期和灌水对冬小麦生物量积累动态特征的影响并实现不同播期与灌水条件下的产量模拟,在吴桥实验站2年(2017—2019年)播期水分大田试验基础上,结合2011—2017年播期水分文献资料,采用“小麦钟”模型发育指数来定量模拟冬小麦的发育期,以Logistic模型定量模拟不同播期和水分处理对地上部生物量积累动态的影响,并建立冬小麦生物量模型,进而构建冬小麦产量模型。结果表明,播期通过影响冬小麦生长旺盛期来影响生物量积累;播期推迟,冬小麦生长旺盛期缩短而使生物量减小。不同水分处理造成的地上部最大生物量的差异主要由生物量的最大积累速率决定,生物量最大积累速率随灌水量的增大呈先增加后下降趋势。基于冬前积温和生长季供水量建立冬小麦生物量与产量模型,冬小麦地上部生物量实测值和模拟值的均方根误差(RMSE)和归一化均方根误差(NRMSE)分别为1980.2 kg/hm^(2)和15.7%,产量实测值和模拟值的RMSE和NRMSE分别为839.7 kg/hm^(2)和10.6%。基于发育指数的Logistic模型能较好地模拟冬小麦的生物量积累,对不同播期与灌水条件下的产量具有较好的预测效果。足墒播种条件下,冬小麦适宜冬前积温为200~600℃·d,生长季适宜供水量为200~450 mm。该研究为华北地区合理调控播期灌水措施提供了科学依据,为不同播期与灌水条件下冬小麦产量预测提供了思路。

灌溉方式对杨树人工林细根分布特征的影响

[目的]探究滴灌对北京市大兴区林场5—6年生欧美107杨树人工林细根分布的影响,为干旱沙地条件下营建人工林提供理论支持。[方法]采用根钻取样法,对比滴灌和常规灌溉条件下细根生物量在不同方向、不同水平距离和不同土层深度的差异。[结果]滴灌没有改变细根的空间分布格局,细根在水平方向的距树干50 cm内,垂直方向的0—40 cm土层集中分布,不同方向的细根分布表现为:株间>对角>行间。滴灌对细根生长和分布的影响受滴灌后形成的湿润带范围影响,株间方向细根生物量在水平和垂直方向的分布特征与对角和行间方向差异明显,湿润带范围内细根生物量均与常规灌溉差异极显著(p<0.01)。[结论]滴灌条件下的杨树人工林较常规灌溉有更多的细根分布,可以更充分利用地下资源,促进林木生长,提高林地生产力。

寿竹不同径阶母竹造林效果比较分析

[目的]研究寿竹不同径阶母竹造林在造林成本、造林成效、笋竹生长、生物量分配特征等方面的差异性,比较不同径阶寿竹母竹在造林中存在的优缺点。[方法]以不同径阶寿竹母竹造林地为试验林,在同样的抚育管理下,造林4年后对全林生长指标进行实测调查及分析比较。[结果]在造林成本方面,发现径阶≤2 cm母竹的造林成本分别比径阶为3~5和≥6 cm母竹造林少4 500、10 500元/hm^2;小母竹造林成林时间平均比大母竹造林成林时间早,但成材时间晚;3~5 cm径阶母竹造林形成的林分,出笋数最多,退笋率最低。[结论]该研究可为寿竹母竹造林的推广种植提供理论依据。

Study on Relationship of Root Morphological Characters and Biomass of Cupressus lusitanica in Different Age Classes

[Objective] The aim was to explore biomass and growth of Cupressus lusitanica seedlings in order to provide technological supports for afforestation. [Method] The introduced Cupressus lusitanica seedlings at different ages were re- searched to explore biomass （ground or underground） morphological shape, surface area and volume of a root system. [Result] As age grew, plant height and ground diameter increased significantly, varying dramatically upon seed provenance, and root-canopy ratio, root length, surface area and volume of seedlings were increas- ing. Specifically, seedlings at two-year-old and three-year-old kept a stable growth; moderate and big roots took higher proportions in a root system; underground parts for a plant required more photosynthetic products; root systems of young seedlings grew to moderate and big roots. [Conclusion] Ground biomass is of correlation with root system indices and the morphological characteristics of root systems are close to biomass. The accumulation capacity of biomass differed for seedlings from differ- ent provenances, even in the same environment and at the same time.

Investigation of Essential or Non-essential Character of Some Hardly Known Trace Elements for Plants

The concentration distribution of essential and non-essential micro-elements of the tissues of healthy organisms shows significant difference. This fact can be used for clarification of the biological role of hardly known trace elements, as well, proving the essential or non-essential character. In case of essential elements the concentration range is rather narrow, the distribution is normal. In case of non-essential elements the interval is wide, the concentration-distribution is log-normal. Measurements and mathematical calculations were carried out for determination of the concentrations and concentration-distributions of some micro-elements, trying to clarify the essentiality or non-essential character of the investigated elements from point of view of plant physiology. Based on the measurements for radish Li and Ni seem to be non-essential trace elements, however in case of Sr the distribution curve suggests an essential character, because the concentration range is not wide.

Biology Migration and Distribution Characteristics of Trace Elements in Reconstructed Soil with Coal Gangue Filling

With mixed gangue,coarse gangue and washed gangue as well as the maize in the reclaimed land in Luling Mine of Huaibei as the research object,the biology migration and distribution characteristics of trace elements in the reconstructed soil with different types of coal gangue filling were studied,the contents of Cu,Pb,Zn,Sn,Hg,Cd and Cr were determined,and the distribution characteristics of the trace elements in the coal gangue and different organs of the maize were analyzed.The results showed that the contents of trace elements were the highest in washed gangue and the least in coarse gangue in the gangue used for the reclamation,and there were significant differences in the enrichment ability of trace elements in different organs of maizes that were planted in reclamation land,of which fruit was weaker than other organs,while leaf presented strong absorption ability.

Characteristics and Carbon Storage of a Typical Mangrove Island Ecosystem in Beibu Gulf,South China Sea

By studying the structural characteristics and carbon storage of the mangrove island ecosystem in the Beibu Gulf,this study provides a scientific basis for mangrove ecological compensation in the coastal areas of Guangxi,South China Sea.On the basis of the unmanned aerial vehicle remote sensing images and a sample plot survey,the object-oriented multi-scale segmentation algorithm is used to extract the mangrove community type information,and one-way analysis of variance is conducted to analyse the structural characteristics of the mangrove community.The carbon storage and carbon density of different mangrove ecosystems were obtained based on the allometric growth equation of mangrove plants.The analysis yielded four main results.(1)The island group covers about 27.10 ha,41.32%(11.20 ha)of which represents mangrove areas.The mangrove forest is widely distributed in the tidal flats around the islands.(2)The main mangrove types were Aegiceras corniculatum,Kandelia obovata+Aegiceras corniculatum,Avicennia marina+Aegiceras corniculatum and Avicennia marina communities.(3)Amongst the mangrove plants,Avicennia marina had the highest biomass(18.52 kg plant^(–1)),followed by Kandelia obovata(7.84 kg plant^(–1))and Aegiceras corniculatum(3.85 kg plant^(–1)).(4)The mangrove carbon density difference was significant.Kandelia obovata had the highest carbon density(148.03 t ha^(–1)),followed by Avicennia marina(104.79 t ha^(–1))and Aegiceras corniculatum(99.24 t ha^(–1)).The carbon storage of the mangrove island ecosystem was 1194.70 t,which was higher than in other areas with the same latitude.The carbon sequestration capacity of the mangrove was relatively strong.