滇油杉林下死可燃物含水率与温湿度关系模型研究     

张蒙蒙  杨凯悦  周汝良 《安徽农业科学》2015,(35):238-240

[目的]研究滇油杉林下死可燃物含水率与温湿度关系模型.[方法]以滇油杉林下三类死可燃物为研究对象,借助于恒温恒湿箱对不同温湿度组合下的含水率进行测定,并研究三类死可燃物含水率与温度、湿度、温温度的关系.[结果]在相同湿度条件下,死可燃物含水率随温度的升高而降低,但在不同的湿度下具有不同的变化规律;在相同温度条件下,死可燃物含水率随相对湿度的增大而增大,但在不同的温度下具有不同的变化规律;温湿度共同作用影响死可燃物的含水率,且不同的死可燃物有不同变化规律.[结论]可燃物含水率是受多种因素影响.滇油杉林下三类死可燃物含水率从小到大依次为粗大死可燃物、腐殖质、细小死可燃物.  相似文献   

杉木人工林树上宿存枯死枝、叶在冠层与在枯枝落叶层分解的比较研究   总被引：5，自引：1，他引：5  

张家城  盛炜彤 《林业科学》2001,37(6):2-10

杉木枯死枝、叶有在树上宿存多年的特性。江西分宜大岗山地区一立地指数 14 ,林龄 13a ,保留密度 2 60 0株·hm- 2 的 1代林 ,树上宿存枯死枝、叶总量达 4 10 8 0kg·hm- 2 ,相当枯枝落叶层生物量的 3 5 4 %。树上宿存枯死枝、叶在冠层的分解速度 ,与置于枯枝落叶层的分解速度的测定结果表明 ,后者比前者快得多。说明在杉木林生长急需养分的速生期和杆材期 ,将树上宿存枯死枝、叶适时地打落于地表 ,使其在枯枝落叶层分解 ,与挂在冠层上的分解相比 ,对林木营养作用不同 ,前者比后者能及时、更多地提供养分。树上宿存枯死枝、叶在林冠下部由低到高呈 4层分布。鉴于各层死亡时间不同 ,经受的分解时间和雨水淋溶的强度也相异 ,其在树冠上的分解速度是分层测定的 ,上下层差异较大。在枯枝落叶层的分解速度也分层测定 ,上下层的差异较小。在枯枝落叶层分解时 ,本实验 1年间枝的各层分解量之和是树冠上分解时的近 2 3倍 ,叶为 5 4倍。在枯枝落叶层分解时 ,1年间各层枝、叶 ,营养元素归还量之和是树冠上分解时的 3 5倍。速生、杆材期 ,适时地将树上宿存枯死枝、叶打落于地表 ,对连栽杉木林长期生产力的保持更是有积极作用  相似文献   

Cryopreservation of dead fish spermatozoa several hours after death of Indian major carp, Labeo rohita and its successful utilization in fish production     

P. Routray  A.K. Choudhary  D.K. Verma  P. Swain  S.D. Gupta 《Aquaculture (Amsterdam, Netherlands)》2006,261(4):1204-1211

Cryopreservation of semen collected from dead fishes showed that it is possible to use it for fish production. We humanely killed individuals of the Indian major carp rohu, Labeo rohita and stored at different temperature regimes of 31 °C, 0 °C, − 10 °C and − 30 °C till 8 h. At every one hour interval semen from these fishes were collected by Pasteur pipette and evaluated for sperm yield/kg body weight, motility, pH, spermatocrit (%) and sperm count. The semen having suitable characteristics such as; 70% spermatocrit or above and motility index of 4 or above was cryopreserved by following a specific protocol. The cryopreserved semen of the dead fishes was stored for 7 days and then thawed in a water bath at 37 °C for 50 s. It was found that up to 8 h, spermatozoa of rohu were viable when stored at 0 °C or − 10 °C. Sperm collected after 8 h of fish death and maintained at 0 °C was the best stored condition that showed 30% larval survival. The spermatozoa collected 8 h after fish death was mostly normal as observed under scanning electron microscope and the total length of rohu spermatozoa was 25-30 μm. The hatchlings produced with this cryopreserved semen grew normally and juvenile fishes of rohu could be produced. This study suggests that germ cells such as spermatozoa of dead fishes can be cryopreserved and utilized for restoration of a species. It has the potential use in cryo-conservation of endangered fishes, restoration of animals through fertilization and genetic manipulation studies.  相似文献   

饲粮中添加啤酒花渣对肉仔鸡死淘率的影响     

冯玉升  魏时来 《安徽农业科学》2014,(13):3913+3915-3913,3915

[目的]探讨啤酒花渣对内仔鸡死淘率的影响.[方法]试验选用300只1日龄AA肉鸡,各试验组在饲粮中分别加入0％、4％、8％、12％、16％和20％啤酒花渣.[结果]各组0～3周、4～6周和全期死淘率从高到低依次为：2组＜3组＜l组＜4组＜6组＜5组.0～6周2组、3组肉鸡全期死淘率比1组增加73.3％和16.7％,而4组、5组、6组比1组分别降低60.0％、93.0％和86.7％.[结论]在肉仔鸡饲粮中添加12％、16％和20％啤酒花渣,可以降低肉仔鸡的死淘率.  相似文献   

Long-term organic phosphorus mineralization in Spodosols under forests and its relation to carbon and nitrogen mineralization     

David L. Achat  Mark R. Bakker  Sylvain Pellerin  Christian Morel 《Soil biology & biochemistry》2010,42(9):1479-1490

In forest soils where a large fraction of total phosphorus (P) is in organic forms, soil micro-organisms play a major role in the P cycle and plant availability since they mediate organic P transformations. However, the correct assessment of organic P mineralization is usually a challenging task because mineralized P is rapidly sorbed and most mineralization fluxes are very weak. The objectives of the present work were to quantify in five forest Spodosols at soil depths of 0-15 cm net mineralization of total organic P and the resulting increase in plant available inorganic P and to verify whether net or gross P mineralization could be estimated using the C or N mineralization rates. Net mineralization of total organic P was derived from the net changes in microbial P and gross mineralization of P in dead soil organic matter. We studied very low P-sorbing soils enabling us to use lower extractants to assess the change in total inorganic P as a result of gross mineralization of P in dead soil organic matter. In addition, to enable detection of gross mineralization of P in dead soil organic matter, a long-term incubation (517 days) experiment was carried out. At the beginning of the experiment, total P contents of the soils were very low (19-51 μg g⁻¹) and were essentially present as organic P (17-44 μg g⁻¹, 85-91%) or microbial P (6-14 μg g⁻¹; 24-39%). Conversely, the initial contents of inorganic P were low (2-7 μg g⁻¹; 9-15%). The net changes in the pool size of microbial P during the 517 days of incubation (4-8 μg g⁻¹) and the amounts of P resulting from gross mineralization of dead soil organic matter (0.001-0.018 μg g⁻¹ day⁻¹; 0.4-9.5 μg g⁻¹ for the entire incubation period) were considerable compared to the initial amounts of organic P and also when compared to the initial diffusive iP fraction (<0.3 μg g⁻¹). Diffusive iP corresponds to the phosphate ions that can be transferred from the solid constituents to the soil solution under a gradient of concentration. Net mineralization of organic P induced an important increase in iP in soil solution (0.6-10 μg g⁻¹; 600-5000% increase) and lower increases in diffusive iP fractions (0.3-5 μg g⁻¹; 300-2000% increase), soil solid constituents having an extremely low reactivity relative to iP. Therefore, soil micro-organisms and organic P transformations play a major role in the bioavailability of P in these forest soils. In our study, the dead soil organic matter was defined as a recalcitrant organic fraction. Probably because gross mineralization of P from this recalcitrant organic fraction was mainly driven by the micro-organisms’ needs for energy, the rates of gross mineralization of C, N and P in the recalcitrant organic fraction were similar. Indirect estimation of gross mineralization of P in dead soil organic matter using the gross C mineralization rate seems thus an alternative method for the studied soils. However, additional studies are needed to verify this alternative method in other soils. No relationships were found between microbial P release and microbial C and N releases.  相似文献   

Coarse woody debris in late-successional Picea abies forests in northern Europe: Variability in quantities and models of decay class dynamics     

Tuomas Aakala 《Forest Ecology and Management》2010

Coarse woody debris pools and their decay class dynamics were studied in three areas of unmanaged boreal forest in northern Finland, and in the Murmansk and Arkhangelsk provinces in northwestern Russia. The study areas had varying climatic and edaphic conditions, and disturbance histories. Living and dead trees (diameter at 1.3 m height ≥10 cm) were measured in five late-successional Picea abies-dominated stands in each of the three areas. Wood density and time since death were determined from randomly sampled dead P. abies, and their decay class dynamics were modeled using stage-based matrix models.  相似文献   

Succession of Diptera on dead beech wood: A 10-year study     

Klaus Hvemeyer  Jürgen Schauermann 《Pedobiologia》2003,47(1):61-75

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Indicators of biodiversity, what do they indicate? - Lessons for conservation of cryptogams in oak-rich forest   总被引：1，自引：0，他引：1  

Björn Nordén  Heidi Paltto  Frank Götmark 《Biological conservation》2007,135(3):369-379

In the Nordic countries, sets of Indicator (Signal) species, predominantly cryptogams, have been used as one measure to find forest stands which may harbour Red List species. Such data could potentially also be used to prioritise among stands for protection as nature reserves. We studied if the number of Signal species indicates the number of Red List species in oak-rich mixed forest in south Sweden. We also explored if species richness of the investigated groups is correlated with the number of Red List or Signal species. In 25 stands, we surveyed epiphytic and epixylic bryophytes and lichens, ground-floor bryophytes, and wood-living fungi. We studied correlations for two datasets; (1) all forest species and (2) deciduous forest specialists. When relating the number of Signal species to the number of Red List species for each taxon and in total, a significant correlation was found for temperate deciduous forest lichens. The number of Signal species was further significantly correlated to total species richness for lichens (all forest species) and for wood-living fungi (both datasets). The number of Red List lichens was correlated to total lichen richness (deciduous forest species). Signal species seem not to be unequivocal in prioritising potential reserves among valuable oak-rich woodlands and surveys by Red List species experts may be needed. Signal species may be more useful for finding relatively valuable sites in a matrix of production forest. Moreover, Signal species seem to be useful surrogates for total cryptogam species richness.  相似文献   

Soil niche effect on species diversity and catabolic activities in an ectomycorrhizal fungal community     

M. Buée  P.E. Courty  D. Mignot  J. Garbaye 《Soil biology & biochemistry》2007,39(8):1947-1955

The species of an ectomycorrhizal (ECM) community were investigated in a temperate oak forest by morphotyping and ITS rDNA sequencing. Thirty-six ECM morphotypes were found at the site. The niche effect (as organic soil, mineral soil or dead woody debris artificially introduced in the soil) on the ECM community structure and on the potential catabolic activities of the most abundant morphotypes was studied. The morphotypes in each niche were subjected to enzymatic tests developed for hydrolytic and oxidative enzymes involved in the decomposition of organic compounds. The ECM community structure varied widely depending on the soil horizon or habitat patch. The species richness was higher in the A1 horizon than in the other niches. Different ECM species had different activity patterns for the eight enzymatic tests while co-occurring in the same niche. Catabolic activities also changed within species between niches. Dead woody debris were extensively colonized by two saprotrophic fungi (Megacollybia platyphylla and Armillaria sp.) and, in this particular niche, ECM morphotypes predominantly belonged to the genera Lactarius and Tomentella. These morphotypes showed high chitinase activities. This study suggested also that some ECM fungi could obtain nutrients via the chitin degradation of dead or live saprobes.  相似文献   

播期播量耦合对小麦越冬死苗的影响   总被引：1，自引：0，他引：1  

吕金岭  郭平银  王凤池  蔡家滨  张振兴 《江西农业学报》2007,19(10):30-31

采用D-饱和最优设计法对播期和播量耦合与小麦越冬死苗的关系进行了研究,结果表明:在10月25日播种、播量为8万基本苗/667 m2条件下,小麦的越冬死苗率最低;晚播和减少播量有利于降低越冬死苗率;播期对小麦越冬死苗率的影响大于播量。  相似文献